Risk of bipolar disorder and schizophrenia in relatives of people with attention-deficit hyperactivity disorder

Investigating the increased risk of schizophrenia and bipolar disorders in relatives of ADHD probands using colocalization analysis of common genetic variants

BACKGROUND

Relatives of ADHD probands are known to be at increased risk of schizophrenia and bipolar disorder, suggesting shared genetic factors. In this study, we aim to identify shared common risk variants (i.e., Single-Nucleotide Polymorphisms, SNPs) between ADHD and schizophrenia, and between ADHD and bipolar disorder.

METHODS

With the summary data from three GWAS, one on ADHD (20,183 cases with ADHD and 35,191 controls), another on schizophrenia (76,755 cases with schizophrenia and 243,649 controls) and another on bipolar disorder (41,917 cases with bipolar disorder and 371,549 controls), we used colocalization analysis to identify SNPs shared by ADHD and schizophrenia, and SNPs shared by ADHD and bipolar disorder. Functional genomic analyses were then conducted on these two sets of shared common genetic variants.

RESULTS

We found that three of the 12 SNPs associated with ADHD colocalized with schizophrenia SNPs and one of the 12 SNPs associated with ADHD colocalized with bipolar disorder. Only 0.4% of the SNPs associated with schizophrenia (2 out of 431) and 2.3% of the SNPs associated with bipolar disorder (2 out of 86), colocalized with ADHD SNPs. Some genes mapped to these shared genetic variants (SCN2A and UNC5D) are involved in the development of the nervous system.

CONCLUSIONS

Using colocalization analysis, the present study uncovers shared genetic variants associated with ADHD and schizophrenia as well as ADHD and bipolar disorder, and may at least partially explain the increased risk of schizophrenia and bipolar disorder in relatives of ADHD probands.

Criminal convictions in males and females diagnosed with attention deficit hyperactivity disorder: A Swedish national registry study

Background

Individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) face an elevated risk of criminal convictions compared to those without ADHD. However, understanding this link involves considering sex differences, coexisting psychiatric conditions, and unmeasured familial factors. This study aimed to explore the connection between ADHD and criminal convictions (both violent and non-violent) in males and females, while also assessing the impact of comorbid psychiatric disorders and familial factors.

Methods

Using Swedish national registers, we identified individuals born between 1986 and 1997 (635,391 males and 600,548 females). ADHD was defined through clinical diagnosis and prescribed medications, while criminal convictions were determined based on Swedish lower court records. Unmeasured familial factors were accounted for using a sibling design approach.

Results

Findings revealed that individuals with ADHD had a notably higher absolute and relative risk of both violent and non-violent criminal convictions compared to those without ADHD. While criminal convictions were more frequent among males with ADHD, females with ADHD exhibited higher relative risks (HR violent 10.50, non-violent 4.04) than their male counterparts (HR violent 6.03, non-violent 3.57). Additionally, lower socioeconomic status (SES) in individuals with ADHD was associated with increased relative risks for criminal convictions compared to individuals with ADHD who had higher SES. Adjusting for childhood and internalizing psychiatric disorders partially attenuated these associations, while substance use disorders (SUD) substantially attenuated them. SUD also contributed to an elevated absolute risk of criminal convictions in both male and female individuals with ADHD. Accounting for unmeasured shared familial factors slightly reduced the estimates, but the association between ADHD and criminal convictions persisted.

Conclusion

In conclusion, ADHD remains a potent independent risk factor for criminal convictions, with varying effects based on gender. This underscores the importance of tailored crime prevention strategies and early interventions for individuals with ADHD, especially when comorbid SUD is present.

Clinical and cognitive characteristics of subjects with schizophrenia and childhood attention-deficit/hyperactivity disorder: Results from the multicentric FACE-SZ cross-sectional dataset

BACKGROUND

Childhood Attention-deficit/hyperactivity disorder (C-ADHD) is a neurodevelopmental disorder, associated with an increased risk of subsequent schizophrenia. The objective of the present study was to determine the prevalence of C-ADHD in schizophrenia and the clinical and cognitive characteristics associated with C-ADHD history in schizophrenia.

METHODS

569 subjects with schizophrenia (74 % men, mean age 30.8) were included in ten expert centers at a national level and tested with a comprehensive battery of clinician-rated, patient-reported scales and cognitive tests. C-ADHD was assessed with the WURS (Wender Utah Rating Scale) self-report questionnaire. Multivariate, correlation, and principal component analyses (PCA) were conducted.

RESULTS

Thirty-nine subjects (N = 39, 6.9 %) were classified in the C-ADHD group. Compared to those without C-ADHD, subjects with C-ADHD were more frequently male, had lower education levels, more severe positive clinical symptoms, more subjective cognitive deficits complaints, and lower medication adherence with small to medium effect sizes. Two cognitive components emerged from the PCA, one component including perceptual reasoning and working memory, and another component including visuospatial search and graphomotor speed, cognitive inhibition/flexibility and central executive functioning. Both components were associated with lower performances in the C-ADHD group.

CONCLUSIONS

C-ADHD is frequent in schizophrenia and associated with more severe positive symptoms and impaired cognitive performances compared to those without C-ADHD. This suggests that the pathophysiological mechanisms contributing to these disorders may lead to the worsening of the cognitive functioning in patients with both disorders. C-ADHD is a relevant clinical marker to discriminate subgroups of schizophrenia with different profiles for a precision-psychiatry approach.

One versus two biological parents with mental disorders: Relationship to educational attainment in the next generation

BACKGROUND

Both maternal and, separately, paternal mental illness are associated with diminished academic attainment among children. However, the differential impacts of diagnostic type and degree of parental burden (e.g. one v. both parents affected) on these functional outcomes are unknown.

METHODS

Using the Swedish national patient (NPR) and multi-generation (MGR) registers, 2 226 451 children (1 290 157 parental pairs), born 1 January 1973-31 December 1997, were followed through 31 December 2013. Diagnostic status of all cohort members was defined for eleven psychiatric disorders, and families classed by exposure: (1) parents affected with any disorder, (2) parents affected with a disorder group (e.g. neuropsychiatric disorders), and (3) parents affected with a specific disorder (e.g. ADHD). Pairs were further defined as 'unaffected,' 'single-affected,', or 'dual-affected.' Among offspring, the study evaluated fulfillment of four academic milestones, from compulsory (primary) school through University (college). Sensitivity analyses considered the impact of child's own mental health, as well as parental education, on main effects.

RESULTS

Marked reductions in the odds of achievement were observed, emerging at the earliest levels of schooling for both single-affected [adjusted odds ratio (aOR), 0.50; 95% CI 0.49-0.51] and dual-affected (aOR 0.29, 95% CI 0.28-0.30) pairs and persisting thereafter [aOR range (single), 0.52-0.65; aOR range (dual), 0.30-0.40]. This pattern was repeated for analyses within diagnosis/diagnostic group. Main results were robust to adjustment for offspring mental health and parent education level.

CONCLUSIONS

Parental mental illness is associated with profound reductions in educational attainment in the subsequent generation, with children from dual-affected families at uniquely high risk.

Co-development of attention deficit hyperactivity disorder and autistic trait trajectories from childhood to early adulthood

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) and autism, defined as traits or disorders, commonly co-occur. Developmental trajectories of ADHD and autistic traits both show heterogeneity in onset and course, but little is known about how symptom trajectories co-develop into adulthood.

METHODS

Using data from a population cohort, the Avon Longitudinal Study of Parents and Children, we examined correlations between ADHD and autistic traits across development, using the Social Communication Disorders Checklist and ADHD subscale of the Strengths and Difficulties Questionnaire. We modelled joint developmental trajectories of parent-reported ADHD and autistic traits between 4 and 25 years, then characterised trajectory classes based on sociodemographic, perinatal, psychopathology, cognition and social functioning variables and tested for associations with neurodevelopmental/psychiatric polygenic scores (PGS).

RESULTS

Three classes of trajectories were identified; a typically developing majority with low-stable ADHD-autistic traits (87%), a male-predominant subgroup with child/adolescent-declining traits (6%) and a subgroup with late-emerging traits (6%). ADHD-autistic trait correlations were greatest in young adulthood for the two nontypically developing classes. There were higher rates of emotional and conduct problems, low IQ, childhood seizures and poor social functioning in the declining and late-emerging classes compared to the low-stable class. Emotional, conduct and peer problems were more prevalent during childhood in the childhood/adolescent-declining class compared to other classes, but were more prevalent in young adulthood in the late-emerging class. Neurodevelopmental/psychiatric PGS also differed: both nontypically developing classes showed elevated ADHD PGS compared to the low-stable group, and the late-emerging group additionally showed elevated schizophrenia PGS and decreased executive function PGS, whereas the declining group showed elevated broad depression PGS.

CONCLUSIONS

Distinct patterns of ADHD-autism co-development are present across development in the general population, each with different characterising factors and genetic signatures as indexed by PGS.

A twin study of genetic and environmental contributions to attention-deficit/hyperactivity disorder over time

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is an increasingly commonly diagnosed neurodevelopmental condition. One possibility is that this reflects a genuine increase in the prevalence of ADHD due to secular environmental changes, yet this hypothesis remains untested. We therefore investigated whether the genetic and environmental variance underlying ADHD, and traits of ADHD, has changed over time.

METHODS

We identified twins born from 1982 to 2008 from the Swedish Twin Registry (STR). We linked the STR with the Swedish National Patient Register and Prescribed Drug Register to identify diagnoses of ADHD and prescriptions of ADHD medication for these twins. We also utilized data collected from participants in the Child and Adolescent Twin Study in Sweden (CATSS), born from 1992 to 2008. Their parents completed a structured ADHD screening tool, which was used to measure traits of ADHD and assign broad screening diagnoses of ADHD. We used the classical twin design to test whether the degree to which variation in these measures was influenced by genetic and environmental variation changed over time.

RESULTS

We included 22,678 twin pairs from the STR and 15,036 pairs from CATSS. The heritability of ADHD in the STR ranged from 66% to 86% over time, although these fluctuations were not statistically significant. We observed a modest increase in variance in ADHD traits, from 0.98 to 1.09. This was driven by small increases in the underlying genetic and environmental variance, with heritability estimated as 64%-65%. No statistically significant changes in variance in screening diagnoses were observed.

CONCLUSIONS

The relative contribution of genetic and environmental factors to ADHD has remained stable over time, despite its increasing prevalence. Thus, changes in the underlying etiology of ADHD over time are unlikely to explain the increase in ADHD diagnoses.

Preterm or early term birth and risk of attention-deficit/hyperactivity disorder: a national cohort and co-sibling study

PURPOSE

To examine risks of attention-deficit/hyperactivity disorder (ADHD) in preterm and early term birth survivors, and potential sex-specific differences.

METHODS

A national cohort study was conducted of all 4061,795 singletons born in Sweden in 1973-2013 who survived infancy, followed up for ADHD identified from nationwide diagnoses and medications through 2018. Poisson regression was used to compute prevalence ratios (PRs), adjusting for sociodemographic and perinatal factors. Co-sibling analyses assessed for confounding by unmeasured shared familial (genetic or environmental) factors.

RESULTS

ADHD prevalences by gestational age at birth were 12.1% for extremely preterm (22-27 weeks), 7.0% for moderately preterm (28-33 weeks), 5.7% for late preterm (34-36 weeks), 6.1% for all preterm (<37 weeks), 5.2% for early term (37-38 weeks), and 4.5% for full-term (39-41 weeks). Adjusted PRs comparing extremely preterm, all preterm, or early term versus full-term, respectively, were 2.35 (95% CI, 2.15-2.57), 1.28 (1.25-1.31), and 1.12 (1.10-1.13) among males, and 2.46 (2.17-2.78), 1.24 (1.20-1.28), and 1.08 (1.06-1.10) among females (P < .001 for each). These associations were virtually unchanged after controlling for shared familial factors. Both spontaneous and medically indicated preterm birth were associated with ADHD (adjusted PRs, 1.21; 95% CI, 1.18-1.24; and 1.39; 1.34-1.43, respectively).

CONCLUSIONS

In this large cohort, preterm and early term birth were associated with increased risks of ADHD in males and females, independently of covariates and shared familial factors.

Prevalence of sleep disorder diagnoses and sleep medication prescriptions in individuals with ADHD across the lifespan: a Swedish nationwide register-based study

BACKGROUND

Consistent evidence suggests a strong association between attention-deficit/hyperactivity disorder (ADHD) and subjectively reported sleep problems. However, the prevalence of clinically ascertained sleep disorder diagnoses and sleep medication prescriptions in individuals with ADHD remains unclear.

OBJECTIVE

To determine the rates of sleep disorder diagnoses and sleep medication prescriptions in children, adolescents and adults with ADHD.

METHODS

We linked Swedish national registers to create a cohort of individuals born 1945-2008. We estimated the absolute and relative risks (using logistic regression models) of different sleep disorder diagnoses and medication prescriptions in individuals with and without ADHD. The analyses were performed across five different age groups: children (5-11 years), adolescents (12-17 years), young adults (18-30 years), middle-aged adults (31-45 years) and older adults (46-60 years).

FINDINGS

Among individuals with ADHD (N=145 490, 2.25% of the cohort), 7.5% had a sleep disorder diagnosis and 47.5% had been prescribed sleep medication. Individuals with ADHD, across all age groups, had a statistically significantly increased risk of having any sleep disorder diagnosis (ORrange=6.4-16.1) and any sleep medication prescription (ORrange=12.0-129.4) compared with individuals without ADHD. While rates of sleep disorders were highest in older adults, the relative risks were highest in youth.

CONCLUSIONS

Individuals with ADHD have a substantially increased risk of sleep disorder diagnoses and sleep medication prescriptions, from childhood into older adulthood.

CLINICAL IMPLICATIONS

More clinical efforts are needed to tackle impairing sleep problems in individuals with ADHD via systematic sleep assessment, appropriate diagnosis, and pharmacological and non-pharmacological interventions. Sleep medication use should be informed by sleep disorder diagnosis.

Association of intellectual disability with violent and sexual crime and victimization: a population-based cohort study

BACKGROUND

Intellectual disability (ID) is associated with violent and sexual offending and victimization, but the importance of neuropsychiatric comorbidity and severity of disability remains unclear.

METHODS

In a register-based cohort study of people born in Sweden 1980-1991 (n = 1 232 564), we investigated associations of mild and moderate/severe ID with any, violent and sexual crimes, and with assault victimization, stratified by comorbid autism and attention deficit hyperactivity disorder (ADHD). We defined ID by attendance at a special school or registered diagnosis and obtained data on criminal convictions and injuries or deaths due to assaults from nationwide registers until end of 2013.

RESULTS

Compared to people without ID, autism or ADHD, men and women with mild or moderate/severe ID and comorbid ADHD had elevated risks of violent crimes [range of hazard ratios (HRs) 4.4-10.4] and assault victimization (HRs 2.0-7.7). Women with mild ID without comorbidities or with comorbid autism also had elevated risks of violent crimes and victimization (HRs 1.8-4.6) compared to women without ID, autism or ADHD. The relative risks of sexual offending and victimization were elevated in men and women with ID without comorbidities (HRs 2.6-12.7). The highest risks for sexual offending in men (HRs 9.4-11.0) and for sexual assault victimization in women (HRs 11.0-17.1) related to ID and comorbid ADHD.

CONCLUSIONS

The elevated risk of violent offending and assault victimization in people with ID is largely explained by comorbid ADHD, whereas ID is independently associated with sexual crimes and victimization, even though absolute risks are low.

Real-life instability in ADHD from young to middle adulthood: a nationwide register-based study of social and occupational problems

BACKGROUND

Studies using self-reports indicate that individuals with ADHD are at increased risk for functional impairments in social and occupational settings, but evidence around real-life instability remains limited. It is furthermore unclear if these functional impairments in ADHD differ across sex and across the adult lifespan.

METHOD

A longitudinal observational cohort design of 3,448,440 individuals was used to study the associations between ADHD and residential moves, relational instability and job shifting using data from Swedish national registers. Data were stratified on sex and age (18-29 years, 30-39 years, and 40-52 years at start of follow up).

RESULTS

31,081 individuals (17,088 males; 13,993 females) in the total cohort had an ADHD-diagnosis. Individuals with ADHD had an increased incidence rate ratio (IRR) of residential moves (IRR 2.35 [95% CI, 2.32-2.37]), relational instability (IRR = 1.07 [95% CI, 1.06-1.08]) and job shifting (IRR = 1.03 [95% CI, 1.02-1.04]). These associations tended to increase with increasing age. The strongest associations were found in the oldest group (40-52 years at start of follow). Women with ADHD in all three age groups had a higher rate of relational instability compared to men with ADHD.

CONCLUSION

Both men and women with a diagnosis of ADHD present with an increased risk of real-life instability in different domains and this behavioral pattern was not limited to young adulthood but also existed well into older adulthood. It is therefore important to have a lifespan perspective on ADHD for individuals, relatives, and the health care sector.

Familial clustering of psychiatric disorders and low IQ

BACKGROUND

Although the ICD and DSM differentiate between different psychiatric disorders, these often share symptoms, risk factors, and treatments. This was a population-based, case-control, sibling study examining familial clustering of all psychiatric disorders and low IQ, using data from the Israel Draft-Board Registry on all Jewish adolescents assessed between 1998 and 2014.

METHODS

We identified all cases with autism spectrum disorder (ASD, N = 2128), severe intellectual disability (ID, N = 9572), attention-deficit hyperactive disorder (ADHD) (N = 3272), psychotic (N = 7902), mood (N = 9704), anxiety (N = 10 606), personality (N = 24 816), or substance/alcohol abuse (N = 791) disorders, and low IQ (⩾2 SDs below the population mean, N = 31 186). Non-CNS control disorders were adolescents with Type-1 diabetes (N = 2427), hernia (N = 29 558) or hematological malignancies (N = 931). Each case was matched with 10 age-matched controls selected at random from the Draft-Board Registry, with replacement, and for each case and matched controls, we ascertained all full siblings. The main outcome measure was the relative recurrence risk (RRR) of the sibling of a case having the same (within-disorder RRR) or a different (across-disorder RRR) disorder.

RESULTS

Within-disorder RRRs were increased for all diagnostic categories, ranging from 11.53 [95% confidence interval (CI): 9.23-14.40] for ASD to 2.93 (95% CI: 2.80-3.07) for personality disorders. The median across-disorder RRR between any pair of psychiatric disorders was 2.16 (95% CI: 1.45-2.43); the median RRR between low IQ and any psychiatric disorder was 1.37 (95% CI: 0.93-1.98). There was no consistent increase in across-disorder RRRs between the non-CNS disorders and psychiatric disorders and/or low IQ.

CONCLUSION

These large population-based study findings suggest shared etiologies among most psychiatric disorders, and low IQ.

Risk of parental major psychiatric disorders in patients with comorbid autism spectrum disorder and attention deficit hyperactivity disorder: A population-based family-link study

OBJECTIVE

Few studies have investigated the parental risk of major psychiatric disorders among patients with comorbid autism spectrum disorder and attention deficit hyperactivity disorder. This study examined the differences in such risk among patients with autism spectrum disorder-only, with attention deficit hyperactivity disorder-only and both conditions.

METHODS

Between 2001 and 2011, we enrolled 132,624 patients with autism spectrum disorder or attention deficit hyperactivity disorder and 1:10 matched controls for age, sex and demographics from the National Health Insurance Database of Taiwan. Poisson regression models were used to examine the risk of five major psychiatric disorders in the patients' parents compared with those of the controls, including schizophrenia, bipolar disorder, major depressive disorder, alcohol use disorder, and substance use disorder. Patients were classified into the autism spectrum disorder-only, attention deficit hyperactivity disorder-only and dual-diagnosis groups.

RESULTS

The parents of attention deficit hyperactivity disorder-only and dual-diagnosis groups had a higher likelihood to be diagnosed with (odds ratios [95% confidence intervals]) schizophrenia (attention deficit hyperactivity disorder: 1.48 [1.39, 1.57]; dual: 1.79 [1.45, 1.20]), bipolar disorder (attention deficit hyperactivity disorder: 1.91 [1.82, 2.01]; dual: 1.81 [1.51, 2.17]), major depressive disorder (attention deficit hyperactivity disorder: 1.94 [1.89, 2.00]; dual: 1.99 [1.81, 2.20]), alcohol use disorder (attention deficit hyperactivity disorder: 1.39 [1.33, 1.45]; dual: 1.20 [1.01, 1.42]) and substance use disorder (attention deficit hyperactivity disorder: 1.66 [1.59, 1.73]; dual: 1.34 [1.13, 1.58]) than the controls. In contrast, the parents of autism spectrum disorder-only group had a higher likelihood to be diagnosed with schizophrenia (1.77 [1.46, 2.15]) and major depressive disorder (1.45 [1.32, 1.61]) and a lower likelihood to be diagnosed with alcohol use disorder (0.68 [0.55, 0.84]) than the controls.

CONCLUSION

The autism spectrum disorder-only group had a different parental incidence of major psychiatric disorders than the attention deficit hyperactivity disorder-only and dual-diagnosis groups. Our findings have implications for clinical practice and future genetic research.

Meta-analysis of personal and familial co-occurrence of Attention Deficit/Hyperactivity Disorder and Bipolar Disorder

BACKGROUND

Attention Deficit Disorder / Hyperactivity (ADHD) and Bipolar Disorder (BD) are highly comorbid disorders. Studies have raised the hypothesis of shared genetic, neurobiological, and clinical factors. This would entail an excess risk of co-occurrence of both disorders.

OBJECTIVE

We present the first meta-analysis of individual and familial associations between ADHD and BD.

METHODS

From 2688 references, 59 were included, with a total of 550,379 ADHD patients, 57,799 BD patients and 12,608,137 controls.

RESULTS

Personal history of ADHD increased the risk of BD (OR = 6.06), and conversely individuals with BD had an increased risk of ADHD (OR = 8.94). First-degree relatives of ADHD patients had an increased risk of BD (OR = 1.94). Offspring of individuals with BD had a higher risk for ADHD (OR = 2.33). Finally, first-degree relatives of BD patients had an increased risk of ADHD (OR = 2.71).

CONCLUSION

We show a clear epidemiological overlap between ADHD and BD, as well as a strong familial association which advocates in favor of a more systematic screening.

The Relationship of Attention-Deficit/Hyperactivity Disorder With Posttraumatic Stress Disorder: A Two-Sample Mendelian Randomization and Population-Based Sibling Comparison Study

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) and posttraumatic stress disorder (PTSD) are associated, but it is unclear if this is a causal relationship or confounding. We used genetic analyses and sibling comparisons to clarify the direction of this relationship.

METHODS

Linkage disequilibrium score regression and 2-sample Mendelian randomization were used to test for genetic correlation (rg) and bidirectional causal effects using European ancestry genome-wide association studies of ADHD (20,183 cases and 35,191 controls) and 6 PTSD definitions (up to 320,369 individuals). Several additional variables were included in the analysis to verify the independence of the ADHD-PTSD relationship. In a population-based sibling comparison (N = 2,082,118 individuals), Cox regression models were fitted to account for time at risk, a range of sociodemographic factors, and unmeasured familial confounders (via sibling comparisons).

RESULTS

ADHD and PTSD had consistent rg (rg range, 0.43-0.52; p <  .001). ADHD genetic liability was causally linked with increased risk for PTSD (β = 0.367; 95% CI, 0.186-0.552; p = 7.68 × 10-5). This result was not affected by heterogeneity, horizontal pleiotropy (Mendelian randomization Egger intercept = 4.34 × 10-4, p = .961), or other phenotypes and was consistent across PTSD datasets. However, we found no consistent associations between PTSD genetic liability and ADHD risk. Individuals diagnosed with ADHD were at a higher risk for developing PTSD than their undiagnosed sibling (hazard ratio = 2.37; 95% CI, 1.98-3.53).

CONCLUSIONS

Our findings add novel evidence supporting the need for early and effective treatment of ADHD, as patients with this diagnosis are at significantly higher risk to develop PTSD later in life.

Association between attention deficit hyperactivity disorder and outcomes after metabolic and bariatric surgery: a nationwide propensity-matched cohort study

BACKGROUND

The risks and benefits of metabolic and bariatric surgery for patients with attention deficit hyperactivity disorder (ADHD) remain to be investigated.

OBJECTIVE

The aim of this study was to assess short- and long-term outcomes after metabolic and bariatric surgery in patients with previous ADHD compared with matched control individuals.

SETTING

Registry based.

METHODS

This 2-staged matched-cohort study included all adults with a body mass index of ≥30 kg/m² who underwent primary Roux-en-Y gastric bypass or sleeve gastrectomy from 2007 until 2017 registered in the Scandinavian Obesity Surgery Registry. Patients with prescribed medication for ADHD were matched with control individuals without ADHD with a follow-up of up to 11 years after surgery.

RESULTS

Among 1431 patients with ADHD and 2862 control individuals (mean body mass index, 42 kg/m²; mean age, 35 years), no difference in weight loss or follow-up attendance over 2 years was seen. ADHD was associated with a higher risk for early postoperative complications (odds ratio [OR] = 1.31; 95% confidence interval [CI], 1.05-1.63), self-harm (hazards ratio [HR] = 1.39; 95% CI, 1.11-1.75), and substance abuse (HR = 1.34; 95% CI, 1.16-1.55), while associations with overall mortality (HR = 1.42; 95% CI, .99-2.03), major adverse cardiovascular and cerebrovascular events (HR = 1.93; 95% CI, .98-3.83), and effects on obesity-related diseases were uncertain. ADHD was associated with a lower health-related quality of life in all aspects before surgery. These differences increased for mental and obesity-related aspects but remained unchanged over time for physical aspects.

CONCLUSIONS

Compared with patients without ADHD, patients treated pharmacologically for ADHD experience similar weight loss and remission of obesity-related diseases without an increased risk for serious complications but report a lower health-related quality of life and have an increased risk of substance abuse and self-harm. This further emphasizes the need for close follow-up care for this group of individuals.

Labor epidural analgesia and subsequent risk of offspring autism spectrum disorder and attention-deficit/hyperactivity disorder: a cross-national cohort study of 4.5 million individuals and their siblings

BACKGROUND

A recent study has suggested that labor epidural analgesia may be associated with increased rates of offspring autism spectrum disorder. Subsequent replication attempts have lacked sufficient power to confidently exclude the possibility of a small effect, and the causal nature of this association remains unknown.

OBJECTIVE

This study aimed to investigate the extent to which exposure to labor epidural analgesia is associated with offspring autism spectrum disorder and attention-deficit/hyperactivity disorder following adjustments for unmeasured familial confounding.

STUDY DESIGN

We identified 4,498,462 singletons and their parents using the Medical Birth Registers in Finland (cohorts born from 1987-2005), Norway (1999-2015), and Sweden (1987-2011) linked with population and patient registries. These cohorts were followed from birth until they either had the outcomes of interest, emigrated, died, or reached the end of the follow-up (at mean ages 13.6-16.8 years), whichever occurred first. Cox regression models were used to estimate country-specific associations between labor epidural analgesia recorded at birth and outcomes (eg, at least 1 secondary care diagnosis of autism spectrum disorder and attention-deficit/hyperactivity disorder or at least 1 dispensed prescription of medication used for the treatment of attention-deficit/hyperactivity disorder). The models were adjusted for sex, birth year, birth order, and unmeasured familial confounders via sibling comparisons. Pooled estimates across all the 3 countries were estimated using inverse variance weighted fixed-effects meta-analysis models.

RESULTS

A total of 4,498,462 individuals (48.7% female) were included, 1,091,846 (24.3%) of which were exposed to labor epidural analgesia. Of these, 1.2% were diagnosed with autism spectrum disorder and 4.0% with attention-deficit/hyperactivity disorder. On the population level, pooled estimates showed that labor epidural analgesia was associated with increased risk of offspring autism spectrum disorder (adjusted hazard ratio, 1.12; 95% confidence interval, 1.10-1.14, absolute risks, 1.20% vs 1.07%) and attention-deficit/hyperactivity disorder (adjusted hazard ratio, 1.20; 95% confidence interval, 1.19-1.21; absolute risks, 3.95% vs 3.32%). However, when comparing full siblings who were differentially exposed to labor epidural analgesia, the associations were fully attenuated for both conditions with narrow confidence intervals (adjusted hazard ratio [autism spectrum disorder], 0.98; 95% confidence interval, 0.93-1.03; adjusted hazard ratio attention-deficit/hyperactivity disorder, 0.99; 95% confidence interval, 0.96-1.02).

CONCLUSION

In this large cross-national study, we found no support for the hypothesis that exposure to labor epidural analgesia causes either offspring autism spectrum disorder or attention-deficit/hyperactivity disorder.

An integrative evolutionary framework for psychopathology

The field of psychopathology is in a transformative phase, and is witnessing a renewed surge of interest in theoretical models of mental disorders. While many interesting proposals are competing for attention in the literature, they tend to focus narrowly on the proximate level of analysis and lack a broader understanding of biological function. In this paper, we present an integrative framework for mental disorders built on concepts from life history theory, and describe a taxonomy of mental disorders based on its principles, the fast-slow-defense model (FSD). The FSD integrates psychopathology with normative individual differences in personality and behavior, and allows researchers to draw principled distinctions between broad clusters of disorders, as well as identify functional subtypes within current diagnostic categories. Simulation work demonstrates that the model can explain the large-scale structure of comorbidity, including the apparent emergence of a general "p factor" of psychopathology. A life history approach also provides novel integrative insights into the role of environmental risk/protective factors and the developmental trajectories of various disorders.

Interplay of ADHD Polygenic Liability With Birth-Related, Somatic, and Psychosocial Factors in ADHD: A Nationwide Study

OBJECTIVE

Attention deficit hyperactivity disorder (ADHD) is a multifactorial neurodevelopmental disorder, yet the interplay between ADHD polygenic risk scores (PRSs) and other risk factors remains relatively unexplored. The authors investigated associations, confounding, and interactions of ADHD PRS with birth-related, somatic, and psychosocial factors previously associated with ADHD.

METHODS

Participants included a random general population sample (N=21,578) and individuals diagnosed with ADHD (N=13,697) from the genotyped Danish iPSYCH2012 case cohort, born between 1981 and 2005. The authors derived ADHD PRSs and identified 24 factors previously associated with ADHD using national registers. Logistic regression was used to estimate associations of ADHD PRS with each risk factor in the general population. Cox models were used to evaluate confounding of risk factor associations with ADHD diagnosis by ADHD PRS and parental psychiatric history, and interactions between ADHD PRS and each risk factor.

RESULTS

ADHD PRS was associated with 12 of 24 risk factors (odds ratio range, 1.03-1.30), namely, small gestational age, infections, traumatic brain injury, and most psychosocial risk factors. Nineteen risk factors were associated with ADHD diagnosis (odds ratio range, 1.20-3.68), and adjusting for ADHD PRS and parental psychiatric history led to only minor attenuations. Only the interaction between ADHD PRS and maternal autoimmune disease survived correction for multiple testing.

CONCLUSIONS

Higher ADHD PRS in the general population is associated with small increases in risk for certain birth-related and somatic ADHD risk factors, and broadly to psychosocial adversity. Evidence of gene-environment interaction was limited, as was confounding by ADHD PRS and family psychiatric history on ADHD risk factor associations. This suggests that the majority of the investigated ADHD risk factors act largely independently of current ADHD PRS to increase risk of ADHD.

Risk and resilience factors impacting the mental health and wellbeing of siblings of individuals with neurodevelopmental conditions: A mixed methods systematic review

OBJECTIVE

This pre-registered systematic review synthesised and evaluated the existing literature on self-reported mental health and wellbeing of siblings of individuals with neurodevelopmental conditions (NDCs).

METHODS

From 2437 identified studies published 2000-2022, 81 studies were included: 14 population- or cohort-based, 39 quantitative, 7 mixed method, and 21 qualitative outcome studies.

RESULTS

Seven sibling mental health (any psychiatric disorder, anxiety, depression, bipolar disorder, schizophrenia, internalising and externalising difficulties) and five wellbeing indicators were identified (quality of life, emotional adjustment, social wellbeing, somatic/physical wellbeing, and resilience/growth). Overall, siblings had increased risk of any psychiatric disorder, but they also reported experiences of growth and resilience, primarily in qualitative studies. 41 risk factors and 24 resilience factors associated with these outcomes were identified; the most frequently cited risk factor was symptom severity of the NDC sibling, while the most common resilience factor was adaptive/active coping at the individual sibling level. Studies showed high methodological heterogeneity and 90 different self-report measures were used.

CONCLUSIONS

Sibling mental health indictors are heterogeneous and cumulative risk factors may result in poorer wellbeing. There is a need for consistent reporting of family and sibling characteristics, a strengths-based approach to assessment, and identification of protective and resilience-promoting factors.

Are neurocognitive abilities and social cognition related to social and role functioning in familial high risk group for psychosis?

AIMS

In this study, we aimed to compare neurocognitive abilities and social cognitive features among adolescent offspring of psychotic individuals and healthy controls.

METHODS

The study sample was composed of offspring of patients with psychotic disorders (n = 30), the high risk group (HR), and age and sex matched healthy controls (n = 32) the Control Group (CG). The psychiatric diagnoses were established by using the KD-SADS. Strengths and Difficulties Questionnaire adolescent and parent forms (SDQ-A, SDQ-P) were used. General functioning status were evaluated by The Children's Global Assessment Scale (CGAS) and Global Functioning Scale: Social and Role Functioning. Wisconsin Cart Sorting Test, Controlled Oral Word Association Test, California Verbal Learning Test, Stroop Colour and Word Test and Trail Making Tests A and B were used to assess neurocognitive abilities; to assess social cognition and empathy skills DANVA-2 and Bryant Empathy Scale were used, respectively.

RESULTS

Among HR 53.33% had at least one psychopathology. SDQ-A, SDQ-P scores were significantly higher, and CGAS, social and role functioning scores were significantly lower in HR. Neurocognitive test scores were significantly worse except for SCWT scores in the HR. No significant differences were obtained in social cognition. A variety of the neurocognitive abilities were significantly correlated with the role functioning. In regression analyses, the most predictive scores were WCST total correct scores and role functioning score.

CONCLUSIONS

HR group showed more impairments in neurocognition, social, role and overall functioning, whereas there was no significant difference in terms of social cognition. Disturbances in neurocognition were correlated with impairments in role functioning.

Attention-deficit/hyperactivity disorder as a risk factor for cardiovascular diseases: a nationwide population-based cohort study

Accumulating evidence suggests a higher risk for cardiovascular diseases among individuals with mental disorders, but very little is known about the risk for overall and specific groups of cardiovascular diseases in people with attention-deficit/hyperactivity disorder (ADHD). To fill this knowledge gap, we investigated the prospective associations between ADHD and a wide range of cardiovascular diseases in adults. In a nationwide population-based cohort study, we identified 5,389,519 adults born between 1941 and 1983, without pre-existing cardiovascular diseases, from Swedish registers. The study period was from January 1, 2001 to December 31, 2013. Incident cardiovascular disease events were identified according to ICD codes. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated using Cox proportional hazards regression model, with ADHD as a time-varying exposure. After an average 11.80 years of follow-up, 38.05% of individuals with ADHD versus 23.57% of those without ADHD had at least one diagnosis of cardiovascular disease (p<0.0001). ADHD was significantly associated with increased risk of any cardiovascular disease (HR=2.05, 95% CI: 1.98-2.13) after adjusting for sex and year of birth. Further adjustments for education level, birth country, type 2 diabetes mellitus, obesity, dyslipidemia, sleep problems and heavy smoking attenuated the association, which however remained significant (HR=1.84, 95% CI: 1.77-1.91). Further adjustment for psychiatric comorbidities attenuated but could not fully explain the association (HR=1.65, 95% CI: 1.59-1.71). The strongest associations were found for cardiac arrest (HR=2.28, 95% CI: 1.81-2.87), hemorrhagic stroke (HR=2.16, 95% CI: 1.68-2.77), and peripheral vascular disease/arteriosclerosis (HR=2.05, 95% CI: 1.76-2.38). Stronger associations were observed in males and younger adults, while comparable associations were found among individuals with or without psychotropic medications and family history of cardiovascular diseases. These data suggest that ADHD is an independent risk factor for a wide range of cardiovascular diseases. They highlight the importance of carefully monitoring cardiovascular health and developing age-appropriate and individualized strategies to reduce the cardiovascular risk in individuals with ADHD.

Correlation of attention deficit hyperactivity disorder with gut microbiota according to the dietary intake of Korean elementary school students

We investigated the impact of dietary patterns on the gut microbiota and concentration of short-chain fatty acids in the feces of Korean elementary school students. The dietary intake and ADHD assessment of 40 Korean elementary school students were analyzed using a dish-based semi-quantitative food frequency questionnaire. Analysis of gut microbiota and short-chain fatty acids composition were performed using the real-time polymerase chain reaction, metagenomics, and gas chromatography methods. The dietary patterns of participants were divided into four groups: healthy, processed food, fish and shellfish, and meat. The participants were also divided into two groups according to their ADHD scores: 0–30, control group; over 30, ADHD group. The ADHD score of the processed food group was significantly higher than that of the healthy group. The processed food and ADHD groups showed significantly higher abundance of harmful bacteria, such as the Enterobacter, Escherichia coli, and Clostridium strains, and markedly lower abundance of beneficial bacteria, such as the Bifidobacterium and Ruminococcus strains, than the control group. The heat maps of metagenomics indicated that each group was separated into distinct clusters, and the processed food and ADHD groups showed significantly lower α-diversity of gut microbiota than the control group. In these groups, the concentration of acetate or butyrate in the feces was significantly lower than that in the control group. These results may indicate that imbalanced diets can disturb the colonic microbial balance and are likely to become a potential risk factor for the prevalence of ADHD.

[The Genetic Basis of ADHD - An Update]

The Genetic Basis of ADHD - An Update Abstract. Genetic risks play an important role in the etiology of attention-deficit/hyperactivity disorder (ADHD). This review presents the current state of knowledge concerning the genetic basis of the disorder. It discusses the results of twin- and family-based studies, linkage and association studies as well as recent findings resulting from Genome Wide Association Studies (GWAS). Furthermore, it elaborates on the relevance of polygenic risk scores, rare variants, and epigenetic alterations, especially in light of findings on genetic pleiotropy in the context of frequent psychiatric comorbidities in patients with ADHD.

Associations of preterm birth, small-for-gestational age, preeclampsia and placental abruption with attention-deficit/hyperactivity disorder in the offspring: Nationwide cohort and sibling-controlled studies

Aim

The aim of this study was to investigate preterm birth, small‐for‐gestational age (SGA), preeclampsia and placental abruption in relation to attention‐deficit/hyperactivity disorder (ADHD) in offspring.

Methods

We conducted a population‐based cohort study among non‐malformed live‐born singleton children in Sweden born during 2002–2014. Using national registries with recorded information, we followed 1,212,201 children for an ADHD diagnosis from 3 to 15 years. We compared ADHD rates between exposure categories using adjusted hazard ratios (HR) with 95% confidence intervals (CI) from Cox proportional hazards models. We also conducted sibling‐controlled analyses among 751,464 full siblings.

Results

There were 27,665 ADHD diagnoses in the cohort. Compared with term birth (≥37 weeks), adjusted HR (95% CI) for ADHD increased with decreasing gestational age: 1.18 (1.11, 1.25), 1.61 (1.37, 1.89) and 2.79 (2.23, 3.49) for 32–36 weeks, 28–31 weeks and 22–27 weeks. Both spontaneous and medically indicated preterm birth were associated with ADHD. SGA was related to 1.62 (1.49, 1.77) times higher ADHD incidence. Preeclampsia, but not placental abruption, was associated with ADHD. Sibling‐controlled analyses showed similar results. Preterm birth did not fully explain the associations of SGA or preeclampsia with ADHD.

Conclusion

Preterm birth, SGA and preeclampsia are related to ADHD incidence in offspring.

Association of Perinatal and Childhood Ischemic Stroke With Attention-Deficit/Hyperactivity Disorder

IMPORTANCE

Early detection of attention-deficit/hyperactivity disorder (ADHD) plays a crucial role in reducing negative effects on everyday life, including academic failure and poor social functioning. Children who survive ischemic strokes risk major disabilities, but their risk of ADHD has not been studied in nationwide cohorts.

OBJECTIVE

To assess the risk of ADHD in children after pediatric ischemic stroke.

DESIGN, SETTING, AND PARTICIPANTS

Participants in this Swedish nationwide cohort study included 1320 children diagnosed with ischemic stroke recorded in linked Swedish national registers from January 1, 1969, to December 31, 2016, without prior ADHD diagnosis. Ten matched controls were identified for each index case, and first-degree relatives were identified for index individuals and controls. Analyses were stratified by perinatal and childhood strokes and presence of comorbid adverse motor outcomes and/or epilepsy. End of follow-up was the date of ADHD diagnosis, death, or December 31, 2016, whichever occurred first. Data analyses were performed August 1 to 28, 2021.

EXPOSURES

Pediatric ischemic stroke.

MAIN OUTCOMES AND MEASURES

Attention-deficit/hyperactivity disorder identified using codes from the International Classification of Diseases, Ninth Revision, and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, and/or prescribed ADHD medication recorded in the Medical Birth Register, National Patient Register, or Prescribed Drug Register after stroke. Cox proportional hazards regression was used to assess adjusted hazard ratios (aHRs) for ADHD after pediatric stroke, adjusting for parental age and ADHD in first-degree relatives.

RESULTS

Of 1320 children with stroke included in the analysis (701 boys [53.1%]), 75 (45 boys [60.0%]) were diagnosed with ADHD after stroke compared with 376 (252 boys [67.0%]) among the controls (aHR, 2.00 [95% CI, 1.54-2.60]). The risk was increased after both perinatal (aHR, 2.75 [95% CI ,1.65-4.60]) and childhood (aHR, 1.82 [95% CI, 1.34-2.48]) strokes and were similar if children born preterm or small for gestational age were excluded. Compared with controls, risks of ADHD were higher among children with perinatal stroke and adverse motor outcomes and/or epilepsy (aHR, 6.17 [95% CI, 2.80-13.62]) than among those without these comorbidities (aHR, 1.65 [95% CI, 0.80-3.42]). However, findings were similar in childhood stroke for children with adverse motor outcomes and/or epilepsy (aHR, 1.80 [95% CI, 1.12-2.89]) and among those without these comorbidities (aHR, 1.92 [95% CI, 1.28-2.90]).

CONCLUSIONS AND RELEVANCE

This cohort study of 1320 children with pediatric ischemic stroke suggests that there is an increased risk of ADHD, particularly in children with adverse motor outcomes and/or epilepsy, compared with controls. The risk increases after childhood strokes regardless of comorbidities.

Genetics in the ADHD Clinic: How Can Genetic Testing Support the Current Clinical Practice?

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with a childhood prevalence of 5%. In about two-thirds of the cases, ADHD symptoms persist into adulthood and often cause significant functional impairment. Based on the results of family and twin studies, the estimated heritability of ADHD approximates 80%, suggests a significant genetic component in the etiological background of the disorder; however, the potential genetic effects on disease risk, symptom severity, and persistence are unclear. This article provides a brief review of the genome-wide and candidate gene association studies with a focus on the clinical aspects, summarizing findings of ADHD disease risk, ADHD core symptoms as dimensional traits, and other traits frequently associated with ADHD, which may contribute to the susceptibility to other comorbid psychiatric disorders. Furthermore, neuropsychological impairment and measures from neuroimaging and electrophysiological paradigms, emerging as potential biomarkers, also provide a prominent target for molecular genetic studies, since they lie in the pathway from genes to behavior; therefore, they can contribute to the understanding of the underlying neurobiological mechanisms and the interindividual heterogeneity of clinical symptoms. Beyond the aforementioned aspects, throughout the review, we also give a brief summary of the genetic results, including polygenic risk scores that can potentially predict individual response to different treatment options and may offer a possibility for personalized treatment for the therapy of ADHD in the future.

What Do We Know About the Genetic Architecture of Psychopathology?

In the second half of the twentieth century, twin and family studies established beyond a reasonable doubt that all forms of psychopathology are substantially heritable and highly polygenic. These conclusions were simultaneously an important theoretical advance and a difficult methodological obstacle, as it became clear that heritability is universal and undifferentiated across forms of psychopathology, and the radical polygenicity of genetic effects limits the biological insight provided by genetically informed studies at the phenotypic level. The paradigm-shifting revolution brought on by the Human Genome Project has recapitulated the great methodological promise and the profound theoretical difficulties of the twin study era. We review these issues using the rubric of genetic architecture, which we define as a search for specific genetic insight that adds to the general conclusion that psychopathology is heritable and polygenic. Although significant problems remain, we see many promising avenues for progress.

Expected final online publication date for the Annual Review of Clinical Psychology, Volume 18 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Hit-and-run: a Swedish nationwide cohort study of serious transport accidents and convictions due to traffic offenses in obsessive-compulsive disorder

PURPOSE

Individuals with obsessive-compulsive disorder (OCD) often report driving-related obsessions, such as fears of causing accidents, but the risk of transport accidents in OCD is unknown. We investigated whether individuals with OCD have an increased risk of serious transport accidents and convictions due to traffic offenses and explored the role of psychiatric comorbidities.

METHODS

We included all individuals ≥ 18 years living in Sweden between 1997 and 2013 (N = 5,760,734). A total of 23,126 individuals had a diagnosis of OCD in the National Patient Register. We also identified 16,607 families with full siblings discordant for OCD. Cox proportional hazards regression models estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for the risk of three outcomes in individuals with OCD, compared to unexposed individuals and their unexposed full siblings: injuries or deaths due to transport accidents, injuries or deaths due to motor vehicle accidents, and convictions related to traffic offenses. Psychiatric comorbidities were systematically adjusted for.

RESULTS

Women, but not men, with OCD had a marginally increased risk of serious transport accidents (adjusted HR = 1.20 [95% CI 1.13-1.28]) and motor vehicle accidents (adjusted HR = 1.20 [95% CI 1.09-1.31]), compared to unaffected individuals. Neither women nor men with OCD had a significantly increased risk of convictions. The sibling comparisons showed no significant associations. When psychiatric comorbidities were adjusted for, several observed associations became non-significant or inversed (HRs and 95% CIs below one).

CONCLUSION

The risks of serious transport accidents and driving-related criminal convictions in OCD are negligible and heavily influenced by psychiatric comorbidity.

Correlation research of susceptibility single nucleotide polymorphisms and the severity of clinical symptoms in attention deficit hyperactivity disorder

OBJECTIVE

To analyze the correlation between susceptibility single nucleotide polymorphisms (SNPs) and the severity of clinical symptoms in children with attention deficit hyperactivity disorder (ADHD), so as to supplement the clinical significance of gene polymorphism and increase our understanding of the association between genetic mutations and ADHD phenotypes.

METHODS

193 children with ADHD were included in our study from February 2017 to February 2020 in the Children's ADHD Clinic of the author's medical institution. 23 ADHD susceptibility SNPs were selected based on the literature, and multiple polymerase chain reaction (PCR) targeted capture sequencing technology was used for gene analysis. A series of ADHD-related questionnaires were used to reflect the severity of the disease, and the correlation between the SNPs of specific sites and the severity of clinical symptoms was evaluated. R software was used to search for independent risk factors by multivariate logistic regression and the "corplot" package was used for correlation analysis.

RESULTS

Among the 23 SNP loci of ADHD children, no mutation was detected in 6 loci, and 2 loci did not conform to Hardy-Weinberg equilibrium. Of the remaining 15 loci, there were 9 SNPs, rs2652511 (SLC6A3 locus), rs1410739 (OBI1-AS1 locus), rs3768046 (TIE1 locus), rs223508 (MANBA locus), rs2906457 (ST3GAL3 locus), rs4916723 (LINC00461 locus), rs9677504 (SPAG16 locus), rs1427829 (intron) and rs11210892 (intron), correlated with the severity of clinical symptoms of ADHD. Specifically, rs1410739 (OBI1-AS1 locus) was found to simultaneously affect conduct problems, control ability and abstract thinking ability of children with ADHD.

CONCLUSION

There were 9 SNPs significantly correlated with the severity of clinical symptoms in children with ADHD, and the rs1410739 (OBI1-AS1 locus) may provide a new direction for ADHD research. Our study builds on previous susceptibility research and further investigates the impact of a single SNP on the severity of clinical symptoms of ADHD. This can help improve the diagnosis, prognosis and treatment of ADHD.

Differentiation and comorbidity of bipolar disorder and attention deficit and hyperactivity disorder in children, adolescents, and adults: A clinical and nosological perspective

Bipolar Disorder (BD) and Attention Deficit and Hyperactivity Disorder (ADHD) are mental disorders with high degree of lifetime comorbidity. Both BD and ADHD are disorders with onset in childhood and early adolescence. Both disorders are often undiagnosed, misdiagnosed, and sometimes overdiagnosed, leading to high rates of morbidity and disability. The psychiatric and behavioral symptoms associated with ADHD and BD have significant overlap. Albeit the existence of a large body of literature, it is far from being clear whether comorbidity can be explained by the confounding overlap of operationally defined criteria or whether it reflects a genuine comorbidity of two biologically distinct disorders. The aim of this paper is to recognize and/or differentiate the pattern of ADHD across the course of BD from a nosological point of view, focusing on specific clinical and neurobiological dimensions. We found that some critical issues may help to fulfill the purpose of our perspective. We suggest that the relationship between ADHD and BD, based on clinical, developmental, and epidemiological commonalities, can be better clarified using four different scenarios.

Attention-deficit/hyperactivity disorder as a risk factor for dementia and mild cognitive impairment: a population-based register study

Background

Previous research has indicated that attention-deficit/hyperactivity disorder (ADHD) is associated with an increased risk for dementia, but studies are scarce and inconclusive. We aimed to investigate the association between ADHD, and dementia and mild cognitive impairment (MCI). Additionally, we aimed to investigate the impact of comorbid conditions, educational attainment, head injuries, other developmental disorders, and sex on the association.

Methods

The study population consisted of 3,591,689 individuals born between 1932 and 1963, identified from Swedish population-based registers. Cases of ADHD, dementia and MCI were defined according to ICD diagnostic codes and ATC codes for medication prescriptions. A Cox proportional hazards model was used to test the associations between ADHD, and dementia and MCI.

Results

Individuals with ADHD had an increased risk for dementia and MCI. After adjusting for sex and birth year, a hazard ratio (HR) was 2.92 (95% confidence interval 2.40–3.57) for dementia, and 6.21 (5.25–7.35) for MCI. Additional adjustment for psychiatric disorders (depression, anxiety, substance use disorder, and bipolar disorder) substantially attenuated the associations, HR = 1.62 (1.32–1.98) for dementia, and 2.54 (2.14–3.01) for MCI. Common metabolic disorders (hypertension, type 2 diabetes, and obesity), sleep disorders, head injuries, educational attainment, and other developmental disorders, had a limited impact on the association. The association between ADHD and dementia was stronger in men.

Conclusions

ADHD is a potential risk factor for dementia and MCI, although the risk significantly attenuates after controlling for psychiatric disorders. Further research is needed to confirm these findings and to explore underlying mechanisms of the associations.

Insights into attention-deficit/hyperactivity disorder from recent genetic studies

Attention-deficit/hyperactivity disorder (ADHD) is a common and highly heritable neurodevelopmental disorder (NDD). In this narrative review, we summarize recent advances in quantitative and molecular genetic research from the past 5-10 years. Combined with large-scale international collaboration, these advances have resulted in fast-paced progress in understanding the etiology of ADHD and how genetic risk factors map on to clinical heterogeneity. Studies are converging on a number of key insights. First, ADHD is a highly polygenic NDD with a complex genetic architecture encompassing risk variants across the spectrum of allelic frequencies, which are implicated in neurobiological processes. Second, genetic studies strongly suggest that ADHD diagnosis shares a large proportion of genetic risks with continuously distributed traits of ADHD in the population, with shared genetic risks also seen across development and sex. Third, ADHD genetic risks are shared with those implicated in many other neurodevelopmental, psychiatric and somatic phenotypes. As sample sizes and the diversity of genetic studies continue to increase through international collaborative efforts, we anticipate further success with gene discovery, characterization of how the ADHD phenotype relates to other human traits and growing potential to use genomic risk factors for understanding clinical trajectories and for precision medicine approaches.

Association of Tourette Syndrome and Chronic Tic Disorder With Cervical Spine Disorders and Related Neurological Complications

Importance

Severe forms of Tourette syndrome or chronic tic disorder (TS/CTD) may involve repeated head jerking. Isolated case reports have described a spectrum of severe neck disorders in individuals with TS/CTD. However, the nature and prevalence of cervical spine disorders in TS/CTD are unknown.

Objective

To establish if TS/CTD are associated with an increased risk of cervical spine disorders and related neurological complications compared with individuals from the general population.

Design, Setting, and Participants

All individuals born from 1973 to 2013 and living in Sweden between 1997 and 2013 were identified. Individuals with a record of TS/CTD diagnosed in specialist settings were matched on age, sex, and county of birth with 10 unexposed individuals randomly selected from the general population. Cox proportional hazards regression models were used to estimate the risk of vascular and nonvascular cervical spine disorders among exposed individuals, compared with unexposed individuals. Models were adjusted for other known causes of cervical spine injury. Data were analyzed from March 19 to May 16, 2021.

Exposures

International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnoses of TS/CTD in the Swedish National Patient Register.

Main Outcomes and Measures

Records of cervical vascular disorders (ie, aneurysm, cerebral infarction, transitory cerebral ischemia) and cervical nonvascular disorders (ie, spondylosis, cervical disc disorders, fractures of the cervical spine, cervicalgia) and cervical surgeries. Covariates included rheumatic disorders, traffic injuries, fall- or sport-related injuries, and attention-deficit/hyperactivity disorder comorbidity.

Results

A total of 6791 individuals with TS/CTD were identified (5238 [77.1%] were male; median [interquartile] age at first diagnosis, 15.6 [11.4-23.7] years) and matched to 67 910 unexposed individuals. Exposed individuals had a 39% increased risk of any cervical spine disorder (adjusted hazard ratio, 1.39; 95% CI, 1.22-1.59). Adjusted hazard ratios for cervical vascular and nonvascular disorders were 1.57 (95% CI, 1.16-2.13) and 1.38 (95% CI, 1.19-1.60), respectively. Risks were similar among men and women.

Conclusions and Relevance

Individuals with severe TS/CTD are at increased risk of cervical spine disorders. These outcomes are relatively rare but may lead to persistent disability in some individuals and thus require close monitoring to facilitate early interventions.

Comedication and Polypharmacy With ADHD Medications in Adults: A Swedish Nationwide Study

Objective: Evidence regarding comedication among individuals with ADHD is lacking, especially in adults. This study investigated comedication and polypharmacy with ADHD medications in adults. Method: We identified adults dispensed with ADHD medications during 2013 in Sweden and matched them to controls. Logistic regression was used to calculate odds ratios (ORs) of receiving other medications. Results: Individuals receiving ADHD medications had higher risk of receiving any major classes of somatic medications (ORs ranged from 4.1, 95% confidence interval [CI] = [4.0, 4.3], to 7.4, 95% CI = [6.5, 8.5] across age groups). They were more likely to receive respiratory system, alimentary tract and metabolic system, and cardiovascular system medications. In addition, they had higher risk of receiving any other psychotropic medications. The proportion of polypharmacy with five or more medication classes increased from 10.1% to 60.4% from 18 to 64 years. Conclusion: Comedication was more common in adults receiving ADHD medications. Potential benefits and harms of comedication and polypharmacy require further research. (J. of Att. Dis. XXXX; XX[X] XX-XX).

Genetic, Clinical, and Sociodemographic Factors Associated With Stimulant Treatment Outcomes in ADHD

OBJECTIVE

Stimulant medications are effective for treating attention deficit hyperactivity disorder (ADHD), yet discontinuation and switch to nonstimulant ADHD medications are common. This study aimed to identify genetic, clinical, and sociodemographic factors influencing stimulant treatment initiation, discontinuation, and switch to nonstimulants in individuals with ADHD.

METHODS

The authors obtained genetic and national register data for 9,133 individuals with ADHD from the Danish iPSYCH2012 sample and defined stimulant treatment initiation, discontinuation, and switch from prescriptions. For each stimulant treatment outcome, they examined associations with polygenic risk scores (PRSs) for psychiatric disorders and clinical and sociodemographic factors using survival analyses, and conducted genome-wide association studies (GWASs) and estimated single-nucleotide polymorphism heritability (h2SNP).

RESULTS

Eighty-one percent of the sample initiated stimulant treatment. Within 2 years, 45% discontinued stimulants and 15% switched to nonstimulants. Bipolar disorder PRS (hazard ratio=1.05, 95% CI=1.02, 1.09) and schizophrenia PRS (hazard ratio=1.07, 95% CI=1.03, 1.11) were associated with discontinuation. Depression, bipolar disorder, and schizophrenia PRSs were marginally but not significantly associated with switch (hazard ratio range, 1.05-1.07). No associations were observed for ADHD and autism PRSs. Individuals diagnosed with ADHD at age 13 or older had higher rates of stimulant initiation, discontinuation, and switch (hazard ratio range, 1.27-2.01). Psychiatric comorbidities generally reduced rates of initiation (hazard ratio range, 0.84-0.88) and increased rates of discontinuation (hazard ratio range, 1.19-1.45) and switch (hazard ratio range, 1.40-2.08). h2SNP estimates were not significantly different from zero. No GWAS hits were identified for stimulant initiation or discontinuation. A locus on chromosome 16q23.3 reached genome-wide significance for switch.

CONCLUSIONS

The study findings suggest that individuals with ADHD with higher polygenic liability for mood and/or psychotic disorders, delayed ADHD diagnosis, and psychiatric comorbidities have a higher risk for stimulant treatment discontinuation and switch to nonstimulants. Despite the study's limited sample size, one putative GWAS hit for switch was identified, illustrating the potential of utilizing genomics linked to prescription databases to advance ADHD pharmacogenomics.

Mapping phenotypic and aetiological associations between ADHD and physical conditions in adulthood in Sweden: a genetically informed register study

BACKGROUND

Emerging evidence suggests increased risk of several physical health conditions in people with ADHD. Only a few physical conditions have been thoroughly studied in relation to ADHD, and there is little knowledge on associations in older adults in particular. We aimed to investigate the phenotypic and aetiological associations between ADHD and a wide range of physical health conditions across adulthood.

METHODS

We did a register study in Sweden and identified full-sibling and maternal half-sibling pairs born between Jan 1, 1932, and Dec 31, 1995, through the Population and Multi-Generation Registers. We excluded individuals who died or emigrated before Jan 1, 2005, and included full-siblings who were not twins and did not have half-siblings. ICD diagnoses were obtained from the National Patient Register. We extracted ICD diagnoses for physical conditions, when participants were aged 18 years or older, from inpatient (recorded 1973-2013) and outpatient (recorded 2001-13) services. Diagnoses were regarded as lifetime presence or absence. Logistic regression models were used to estimate the associations between ADHD (exposure) and 35 physical conditions (outcomes) in individuals and across sibling pairs. Quantitative genetic modelling was used to estimate the extent to which genetic and environmental factors accounted for the associations with ADHD.

FINDINGS

4 789 799 individuals were identified (2 449 146 [51%] men and 2 340 653 [49%] women), who formed 4 288 451 unique sibling pairs (3 819 207 full-sibling pairs and 469 244 maternal half-sibling pairs) and 1 841 303 family clusters (siblings, parents, cousins, spouses). The mean age at end of follow-up was 47 years (range 18-81; mean birth year 1966); ethnicity data were not available. Adults with ADHD had increased risk for most physical conditions (34 [97%] of 35) compared with adults without ADHD; the strongest associations were with nervous system disorders (eg, sleep disorders, epilepsy, dementia; odds ratios [ORs] 1·50-4·62) and respiratory diseases (eg, asthma, chronic obstructive pulmonary disease; ORs 2·42-3·24). Sex-stratified analyses showed similar patterns of results in men and women. Stronger cross-disorder associations were found between full-siblings than between half-siblings for nervous system, respiratory, musculoskeletal, and metabolic diseases (p<0·007). Quantitative genetic modelling showed that these associations were largely explained by shared genetic factors (60-69% of correlations), except for associations with nervous system disorders, which were mainly explained by non-shared environmental factors.

INTERPRETATION

This mapping of aetiological sources of cross-disorder overlap can guide future research aiming to identify specific mechanisms contributing to risk of physical conditions in people with ADHD, which could ultimately inform preventive and lifestyle intervention efforts. Our findings highlight the importance of assessing the presence of physical conditions in patients with ADHD.

FUNDING

Swedish Research Council; Swedish Brain Foundation; Swedish Research Council for Health, Working Life, and Welfare; Stockholm County Council; StratNeuro; EU Horizon 2020 research and innovation programme; National Institute of Mental Health.

Familial co-aggregation of attention-deficit/hyperactivity disorder and autoimmune diseases: a cohort study based on Swedish population-wide registers

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) has been associated with several autoimmune diseases (AD), both within individuals and across relatives, implying common underlying genetic or environmental factors in line with studies indicating that immunological mechanisms are key to brain development. To further elucidate the relationship between ADHD and autoimmunity we performed a population-wide familial co-aggregation study.

METHODS

We linked Swedish national registries, defined a birth cohort with their biological relatives and identified individuals diagnosed with ADHD and/or 13 ADs. The cohort included 5 178 225 individuals born between 1960 and 2010, of whom 118 927 (2.30%) had been diagnosed with ADHD. We then investigated the associations between ADHD and ADs within individuals and across relatives, with logistic regression and structural equation modelling.

RESULTS

Within individuals, ADHD was associated with a diagnosis of any of the 13 investigated ADs (adjusted odds ratio (OR) =1.34, 95% confidence interval (CI) = 1.30-1.38) as well as several specific ADs. Familial co-aggregation was observed. For example, ADHD was associated with any of the 13 ADs in mothers (OR = 1.29, 95% CI = 1.26-1.32), fathers (OR = 1.14, 95% CI = 1.11-1.18), full siblings (OR = 1.19, 95% CI = 1.15-1.22), aunts (OR = 1.12, 95% CI = 1.10-1.15), uncles (OR = 1.07, 95% CI = 1.05-1.10) and cousins (OR = 1.04, 95% CI = 1.03-1.06). Still, the absolute risks of AD among those with ADHD were low. The genetic correlation between ADHD and a diagnosis of any of the investigated ADs was 0.13 (95% CI = 0.09-0.17) and the environmental correlation was 0.02 (95% CI = -0.03-0.06).

CONCLUSIONS

We found that ADHD and ADs co-aggregate among biological relatives, indicating that the relationship between ADHD and autoimmune diseases may in part be explained by shared genetic risk factors. The patterns of familial co-aggregation of ADHD and ADs do not readily support a role of maternal immune activation in the aetiology of ADHD. The findings have implications for aetiological models of ADHD. However, screening for autoimmunity among individuals with ADHD is not warranted.

Sex differences in parent-offspring recurrence of attention-deficit/hyperactivity disorder

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder sharing genetic risk factors with other common psychiatric disorders. However, intergenerational recurrence patterns of ADHD from parents to sons and daughters are not known. We aimed to examine the risk of ADHD in offspring of parents with ADHD and parents with other psychiatric disorders by parental and offspring sex, using parents without the specific disorders as comparison.

METHODS

In a generation study linking data from several population-based registries, all Norwegians born 1967-2011 (n = 2,486,088; Medical Birth Registry of Norway) and their parents were followed to 2015. To estimate intergenerational recurrence risk, we calculated prevalence differences (PD) and the relative risk (RR) of ADHD in offspring by parental ADHD, bipolar disorder (BD), schizophrenia spectrum disorder (SCZ), major depression (MDD), all by parental and offspring sex.

RESULTS

The absolute prevalence of ADHD in offspring of parents with ADHD was very high, especially in sons of two affected parents (41.5% and 25.1% in sons and daughters, respectively), and far higher than in offspring of parents with BD, SCZ or MDD. Intergenerational recurrence risks were higher for maternal than paternal ADHD (RR_maternal 8.4, 95% confidence interval (CI) 8.2-8.6 vs. RR_paternal 6.2, 6.0-6.4) and this was also true on the absolute scale (PD_maternal 21.1% (20.5-21.7) vs. PD_paternal 14.8% (14.3-15.4)). RRs were higher in daughters, while PDs higher in sons. Parental SCZ, BD and MDD were associated with an approximately doubled risk of offspring ADHD compared to parents without the respective disorders, and estimates did not differ significantly between daughters and sons.

CONCLUSIONS

The intergenerational recurrence risks of ADHD were high and higher from mothers with ADHD than fathers with ADHD. Other parental psychiatric disorders also conferred increased risk of offspring ADHD, but far lower, indicating a sex- and diagnosis-specific intergenerational recurrence risk in parents with ADHD.

Identification of genetic overlap and novel risk loci for attention-deficit/hyperactivity disorder and bipolar disorder

Differential diagnosis between childhood onset attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) remains a challenge, mainly due to overlapping symptoms and high rates of comorbidity. Despite this, genetic correlation reported for these disorders is low and non-significant. Here we aimed to better characterize the genetic architecture of these disorders utilizing recent large genome-wide association studies (GWAS). We analyzed independent GWAS summary statistics for ADHD (19,099 cases and 34,194 controls) and BD (20,352 cases and 31,358 controls) applying the conditional/conjunctional false discovery rate (condFDR/conjFDR) statistical framework that increases the power to detect novel phenotype-specific and shared loci by leveraging the combined power of two GWAS. We observed cross-trait polygenic enrichment for ADHD conditioned on associations with BD, and vice versa. Leveraging this enrichment, we identified 19 novel ADHD risk loci and 40 novel BD risk loci at condFDR <0.05. Further, we identified five loci jointly associated with ADHD and BD (conjFDR < 0.05). Interestingly, these five loci show concordant directions of effect for ADHD and BD. These results highlight a shared underlying genetic risk for ADHD and BD which may help to explain the high comorbidity rates and difficulties in differentiating between ADHD and BD in the clinic. Improving our understanding of the underlying genetic architecture of these disorders may aid in the development of novel stratification tools to help reduce these diagnostic difficulties.

Assisted Reproductive Techniques, ADHD, and School Performance

OBJECTIVES

To examine the long-term impact of assisted reproductive techniques (ART) on offspring neurodevelopment, accounting for parental factors and the role of infertility.

METHODS

Linkage of national registers allowed follow-up of >2.4 million children born in Sweden 1986-2012. Information on ART was retrieved from fertility clinics, medical records, and maternal self-report. Attention-deficit/hyperactivity disorder (ADHD) was identified from specialist diagnosis and/or use of medication through 2018. School performance was assessed from records of ninth year final grade averages (0-20) and eligibility for upper secondary school through 2017.

RESULTS

Children conceived with ART had lower risk of ADHD (hazard ratio 0.83; 95% confidence interval [CI]: 0.80 to 0.87) and did better in school (grade mean difference 1.15; 95% CI: 1.09 to 1.21 and eligibility odds ratio 1.53; 95% CI: 1.45 to 1.63) compared with all other children. Differences in parental characteristics explained and even reversed associations, whereas no disadvantage was seen when the comparison was restricted to children of couples with known infertility (adjusted hazard ratio 0.95; 95% CI: 0.90 to 1.00, adjusted mean difference 0.05; 95% CI: -0.01 to 0.11, and adjusted odds ratio 1.03; 95% CI: 0.96 to 1.10). Among children conceived with ART, there was furthermore no indication that intracytoplasmic sperm injection (compared with standard in vitro fertilization) or frozen (compared with fresh) embryo transfer had any adverse influence.

CONCLUSIONS

With this nationwide, long-term follow-up, we provide additional reassurance concerning offspring neurodevelopment after use of ART, finding no indication for concern about risk of ADHD or school performance in adolescence.

Healthcare utilization and costs of psychiatric and somatic comorbidities associated with newly diagnosed adult ADHD

BACKGROUND

Psychiatric and somatic problems in young adulthood have been found to be main drivers of costs in individuals with childhood ADHD. However, knowledge of the patterns of healthcare utilization and costs of comorbidities in middle-aged adults with newly diagnosed ADHD is very limited.

METHOD

We studied individuals born 1966-1978 (from the Swedish Total Population Register) with newly diagnosed ADHD between the ages of 30-45 years and individuals without ADHD matched on birthdate, birth county, and sex. Healthcare utilization and expenditure for psychiatric and somatic disorders were obtained over four years (two years pre- and post-initial ADHD diagnosis).

RESULTS

Middle-aged adults with newly diagnosed ADHD showed higher levels of healthcare utilization and costs (outpatient, inpatient, medications) for psychiatric and somatic comorbidities relative to adults without ADHD, both before and after the initial diagnosis. Females showed greater average group differences across the study period for medication prescriptions than males. Total incremental annual costs per capita were €2478.76 in adults with ADHD relative to those without, and costs were mainly driven by inpatient care. Psychiatric outpatient visits were statistically significantly higher the year before the ADHD diagnosis compared with two years before and after the diagnosis.

CONCLUSION

This study demonstrates the substantial burden of psychiatric and somatic comorbidities in middle-aged adults newly diagnosed with ADHD. Psychiatric outpatient visits peaked in the year leading up to the ADHD diagnosis. Findings further suggested that females with ADHD may seek more treatment for comorbidities than males, which may reflect a general female tendency.

Association of Attention-Deficit/Hyperactivity Disorder in Childhood and Adolescence With the Risk of Subsequent Psychotic Disorder: A Systematic Review and Meta-analysis

IMPORTANCE

Growing evidence supports an association between attention-deficit/hyperactivity disorder (ADHD) in childhood and subsequent psychotic disorders. Both disorders share physiopathological features such as attention deficits, dopaminergic imbalance, and genetic susceptibility. However, the results of epidemiologic studies have been conflicting.

OBJECTIVE

To provide a quantitative synthesis of studies exploring the association between ADHD and the risk of subsequent psychotic disorder.

DATA SOURCES

A systematic literature search of the MEDLINE, Scopus, PsycInfo, and Web of Science databases was performed from inception until the final analysis on July 7, 2020. No restriction of language was applied.

STUDY SELECTION

Cohort and case-control studies examining the relative risk of developing a psychotic disorder in people diagnosed with ADHD at younger than 18 years compared with control individuals without ADHD.

DATA EXTRACTION AND SYNTHESIS

Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines were followed in reporting results. Two independent reviewers extracted the data and assessed the risk of bias of individual studies using the Newcastle-Ottawa Scale. Preferably adjusted odds ratios (aORs) or hazard ratios from the identified studies were extracted, and ORs were computed when they were not adjusted. A random-effects model was used to calculate the pooled relative effect using the meta package in R.

MAIN OUTCOMES AND MEASURES

An association between ADHD (exposure) and psychotic disorder (outcomes); both diagnoses were based on international classification.

RESULTS

A total of 15 studies were included in the review. Twelve studies were pooled in the meta-analysis, representing 1.85 million participants. A diagnosis of ADHD in childhood was associated with a significant increase in the risk of subsequent psychotic disorder, with a pooled relative effect of 4.74 (95% CI, 4.11-5.46; I2 = 43% [95% CI, 0%-70%]). No significant between-group differences were found for subgroup analyses according to psychotic disorder (odds ratio [OR], 5.04; 95% CI, 4.36-5.83) or schizophrenia (OR, 4.59; 95% CI, 3.83-5.50) outcomes, cohort (OR, 4.64; 95% CI, 4.04-5.34) or case-control (OR, 6.81; 95% CI, 4.21-11.03) study design, and adjusted (OR, 4.72; 95% CI, 4.11-5.46) or unadjusted (OR, 3.81; 95% CI, 1.39-10.49) estimates. Meta-regressions were not significant when sex and bias score were used as covariates. No evidence of publication bias was found.

CONCLUSIONS AND RELEVANCE

These findings suggest that childhood ADHD is associated with an increased risk of a subsequent psychotic disorder. Further studies are required to determine the mechanisms linking these common conditions and whether early intervention for ADHD might reduce the risk of subsequent psychotic disorder.

Detecting local genetic correlations with scan statistics

Genetic correlation analysis has quickly gained popularity in the past few years and provided insights into the genetic etiology of numerous complex diseases. However, existing approaches oversimplify the shared genetic architecture between different phenotypes and cannot effectively identify precise genetic regions contributing to the genetic correlation. In this work, we introduce LOGODetect, a powerful and efficient statistical method to identify small genome segments harboring local genetic correlation signals. LOGODetect automatically identifies genetic regions showing consistent associations with multiple phenotypes through a scan statistic approach. It uses summary association statistics from genome-wide association studies (GWAS) as input and is robust to sample overlap between studies. Applied to seven phenotypically distinct but genetically correlated neuropsychiatric traits, we identify 227 non-overlapping genome regions associated with multiple traits, including multiple hub regions showing concordant effects on five or more traits. Our method addresses critical limitations in existing analytic strategies and may have wide applications in post-GWAS analysis.

Attention-deficit/hyperactivity disorder and occupational outcomes: The role of educational attainment, comorbid developmental disorders, and intellectual disability

Background

Individuals with ADHD are at increased risk for poor occupational outcomes. Educational attainment and psychiatric comorbidity may be important contributing factors for these outcomes, but the role of these factors is not well characterized. This study aimed to investigate the associations between ADHD and occupational outcomes, and to examine the influence of educational attainment, comorbid developmental disorders and intellectual disability on these associations.

Methods

We linked the Swedish population graduating from compulsory school 1998–2008 (N = 1.2 millions) to population-wide register-based data on clinical psychiatric diagnoses and medications, objective annual measures of educational, and occupational outcomes. Individuals were followed for between 6 to 16 years after graduation.

Results

Individuals with ADHD had annually on average 17 percent lower income, ratio = 0.83 (95% CI 0.83–0.84), 12.19 (11.89–12.49) more days of unemployment, and a higher likelihood of receiving disability pension, odds-ratio = 19.0 (18.4–19.6), compared to controls. Comorbid diagnoses of intellectual disability and developmental disorder explained most of the association between ADHD and disability pension, while lifetime educational attainment partially explained associations between ADHD and all occupational outcomes. Analyses of occupational trajectories found that income was lower and unemployment elevated relative to controls with the same educational attainment. Higher educational attainment correlated with higher income similarly among individuals with ADHD and controls after accounting for individual background factors.

Conclusions

The occupational burden associated with ADHD is substantial. Comorbid developmental disorders, intellectual disability and educational difficulties (e.g., failing grades) from childhood to adulthood are important factors to consider when designing interventions to improve occupational outcomes in individuals with ADHD.

Mania symptoms in a Swedish longitudinal population study: The roles of childhood trauma and neurodevelopmental disorders

BACKGROUND

Adult psychiatric disorders are associated with both childhood traumatic experiences (CTEs) and neurodevelopmental disorders (NDDs). CTEs and NDDs frequently co-occur in childhood, but their combined risk effect on the emergence of juvenile mania symptoms has not yet been examined.

METHODS

In a population-representative Swedish twin study, CTEs and NDDs were assessed in 3,348 nine-year old twins born between 1998 and 2001, and treated as dichotomous predictors (any CTEs, any NDDs). Follow-up data were gathered at age 15 through parental reports of mania symptoms, yielding a symptom count score.

RESULTS

Both CTEs and NDDs at age 9 contributed uniquely to an increase in mania symptoms at age 15. Children with both risk factors had 1.6 times the rate of mania symptoms as children with CTEs-only (Incidence rate ratio [IRR] 1.63, 95% CI 1.37-1.93), and 1.3 times the rate of mania symptoms as children with NDDs-only (IRR 1.26, 95% CI 1.06-1.50). There was no evidence for an interactive effect of CTEs and NDDs. NDDs showed a trend towards having a larger effect on mania symptoms than CTEs (NDDs-only vs. CTEs-only: IRR 1.29, 95% CI 0.99-1.68).

LIMITATIONS

Although it is a strength of the study that the data on exposures and outcome were collected prospectively, parental recall of CTEs was required and CTEs may be under-reported.

CONCLUSIONS

NDDs are at least as important as CTEs in the development of mania symptoms, and their risk is additive. Those with a history of both CTEs and NDDs should be monitored closely for the development of more severe psychiatric presentations.

Neonatal jaundice, attention deficit hyperactivity disorder and familial effects: A Swedish register study with sibling analysis

AIM

Neonatal jaundice is associated with higher risk of attention deficit hyperactivity disorder (ADHD), but it is unclear if the association is influenced by genetic and other familial factors. In this large population-based study, we investigated the association between neonatal jaundice and ADHD while adjusting for familial factors.

METHODS

We linked several Swedish registers to identify all singleton births without congenital malformations between 1992 and 2000 (n = 814 420, including 384 290 full siblings) and followed them up until 2009. We calculated hazard ratios (HRs) for the association between neonatal jaundice and ADHD, adjusting for pregnancy, delivery and neonatal characteristics including prematurity, and parental age and education. We repeated the analyses among siblings to adjust for shared familial factors.

RESULTS

At a population level, children treated for neonatal jaundice had an increased risk of ADHD (adjusted HR (aHR): 1.13, 95% CI: 1.05-1.22). In the sibling comparisons, there was no clear association between neonatal jaundice and ADHD (aHR: 1.03, 95% CI: 0.82-1.29).

CONCLUSION

We found no evidence of an independent association between neonatal jaundice and ADHD within siblings in this large population-based study, suggesting that the association is probably influenced by shared familial factors, such as parental genetic and/or lifestyle effects.

Comorbidity of ADHD and adult bipolar disorder: A systematic review and meta-analysis

Attention-deficit / hyperactivity disorder (ADHD) and Bipolar Disorder (BD) are common mental disorders with a high degree of comorbidity. However, no systematic review with meta-analysis has aimed to quantify the degree of comorbidity between both disorders. To this end we performed a systematic search of the literature in October 2020. In a meta-analysis of 71 studies with 646,766 participants from 18 countries, it was found that about one in thirteen adults with ADHD was also diagnosed with BD (7.95 %; 95 % CI: 5.31-11.06), and nearly one in six adults with BD had ADHD (17.11 %; 95 % CI: 13.05-21.59 %). Substantial heterogeneity of comorbidity rates was present, highlighting the importance of contextual factors: Heterogeneity could partially be explained by diagnostic system, sample size and geographical location. Age of BD onset occurred earlier in patients with comorbid ADHD (3.96 years; 95 % CI: 2.65-5.26, p < 0.001). Cultural and methodological differences deserve attention for evaluating diagnostic criteria and clinicians should be aware of the high comorbidity rates to prevent misdiagnosis and provide optimal care for both disorders.

Behavioral Tasks Evaluating Schizophrenia-like Symptoms in Animal Models: A Recent Update

BACKGROUND

Schizophrenia is a serious mental illness that affects more than 21 million people worldwide. Both genetics and the environment play a role in its etiology and pathogenesis. Symptoms of schizophrenia are mainly categorized into positive, negative, and cognitive. One major approach to identify and understand these diverse symptoms in humans has been to study behavioral phenotypes in a range of animal models of schizophrenia.

OBJECTIVE

We aimed to provide a comprehensive review of the behavioral tasks commonly used for measuring schizophrenia-like behaviors in rodents together with an update of the recent study findings.

METHODS

Articles describing phenotypes of schizophrenia-like behaviors in various animal models were collected through a literature search in Google Scholar, PubMed, Web of Science, and Scopus, with a focus on advances over the last 10 years.

RESULTS

Numerous studies have used a range of animal models and behavioral paradigms of schizophrenia to develop antipsychotic drugs for improved therapeutics. In establishing animal models of schizophrenia, the candidate models were evaluated for schizophrenia-like behaviors using several behavioral tasks for positive, negative, and cognitive symptoms designed to verify human symptoms of schizophrenia. Such validated animal models were provided as rapid preclinical avenues for drug testing and mechanistic studies.

CONCLUSION

Based on the most recent advances in the field, it is apparent that a myriad of behavior tests are needed to confirm and evaluate the congruency of animal models with the numerous behaviors and clinical signs exhibited by patients with schizophrenia.

Do borderline personality disorder and attention-deficit/hyperactivity disorder co-aggregate in families? A population-based study of 2 million Swedes

Large-scale family studies on the co-occurrence of attention-deficit/hyperactivity disorder (ADHD) and borderline personality disorder (BPD) are lacking. Thus, we aimed to estimate the co-occurrence and familial co-aggregation of clinically ascertained ADHD and BPD diagnoses using the entire Swedish population. In a register-based cohort design we included individuals born in Sweden 1979-2001, and identified their diagnoses during 1997-2013; in total, 2,113,902 individuals were included in the analyses. We obtained clinical diagnoses of ADHD and BPD from inpatient and outpatient care. Individuals with an ADHD diagnosis had an adjusted (for birth year, sex, and birth order) odds ratio (aOR) of 19.4 (95% confidence interval [95% CI] = 18.6-20.4) of also having a BPD diagnosis, compared to individuals not diagnosed with ADHD. Having a sibling with ADHD also increased the risk for BPD (monozygotic twins, aOR = 11.2, 95% CI = 3.0-42.2; full siblings, aOR = 2.8, 95% CI = 2.6-3.1; maternal half-siblings, aOR = 1.4, 95% CI = 1.2-1.7; paternal half-siblings, aOR = 1.5, 95% CI = 1.3-1.7). Cousins also had an increased risk. The strength of the association between ADHD and BPD was similar in females and males, and full siblings showed similar increased risks regardless of sex. Among both males and females, ADHD and BPD co-occur within individuals and co-aggregate in relatives; the pattern suggests shared genetic factors and no robust evidence for etiologic sex differences was found. Clinicians should be aware of increased risks for BPD in individuals with ADHD and their relatives, and vice versa.

Lifetime psychopathology in child and adolescent offspring of parents diagnosed with schizophrenia or bipolar disorder: a 2-year follow-up study

Having one parent diagnosed with a severe mental disorder is considered one of the main risk factors for developing that disorder in adulthood, and it also increases the risk of a wide range of mental disorders in the offspring. The aim of this study is to compare the prevalence of several psychopathological diagnoses, the presence of prodromal symptoms, and global functioning in offspring of parents with schizophrenia or bipolar disorder and in offspring of controls at baseline and 2-year follow-up. This study included 41 offspring of parents with schizophrenia, 90 offspring of parents with bipolar disorder, and 107 offspring of controls (mean age 11.7 ± 3.2 at baseline and 13.9 ± 3.2 at follow-up). The prevalence of psychopathology and comorbidity was higher in offspring of parents with schizophrenia and offspring of parents with bipolar disorder than in offspring of controls at baseline and at 2-year follow-up. Interestingly, mood disorders were more prevalent in offspring of parents with bipolar disorder and disruptive disorders were more prevalent in offspring of parents with schizophrenia. Prodromal symptoms were more frequent in offspring of parents with schizophrenia than in offspring of controls, while the offspring of parents with bipolar disorder showed an intermediate pattern. Finally, global functioning was lower in the offspring of parents with schizophrenia than the offspring of parents with bipolar disorder and the offspring of controls. Screening patients' children is clinically relevant, since, as a group, they have an elevated risk of developing a psychiatric disorder and of experiencing their first symptoms during childhood and adolescence.