Childhood attention-deficit/hyperactivity disorder symptoms and the development of adolescent alcohol problems: A prospective, population-based study of Swedish twins

Executive Function as an Underlying Mechanism of Alcohol Use, Aggression, and ADHD

Background

Executive functioning (EF) has been proposed as a transdiagnostic risk factor for externalizing disorders and behavior more broadly, including attention-deficit/hyperactivity disorder (ADHD), aggression, and alcohol use. Previous research has demonstrated both phenotypic and genetic overlap among these behaviors, but has yet to examine EF as a common causal mechanism. The current study examined reciprocal causal associations between EF and several externalizing behaviors using a Mendelian randomization (MR) approach.

Methods

Two-sample MR was conducted to test causal associations between EF and externalizing behaviors. Summary statistics from several genome-wide association studies (GWASs) were used in these analyses, including GWASs of EF, ADHD diagnostic status, drinks per week, aggressive behavior, and alcohol use disorder (AUD) diagnostic status. Multiple estimation methods were employed to account for horizontal pleiotropy (e.g., inverse variance weighted, MR-PRESSO, MR-MIX).

Results

EF demonstrated significant causal relationships with ADHD (P < 0.01), AUD (P < 0.03), and alcohol consumption (P < 0.01) across several estimation methods. Reciprocally, ADHD showed a significant causal influence on EF (P < 0.03). Nonetheless, caution should be used when interpreting these findings as there was some evidence for horizontal pleiotropy in the effect of EF on ADHD and significant heterogeneity in variant effects in the other relations tested. There were no significant findings for aggression.

Conclusions

Findings suggest that EF may be a causal mechanism underlying some externalizing behaviors, including ADHD and alcohol use, and that ADHD may also lead to lower performance on EF tasks.

Intergenerational transmission of genetic risk for hyperactivity and inattention. Direct genetic transmission or genetic nurture?

Background

Hyperactivity and inattention, the symptoms of ADHD, are marked by high levels of heritability and intergenerational transmission. Two distinct pathways of genetic intergenerational transmission are distinguished: direct genetic transmission when parental genetic variants are passed to the child's genome and genetic nurture when the parental genetic background contributes to the child's outcomes through rearing environment. This study assessed genetic contributions to hyperactivity and inattention in childhood through these transmission pathways.

Methods

The sample included 415 families from the Quebec Newborn Twin Study. Twins' hyperactivity and inattention were assessed in early childhood by parents and in primary school by teachers. The polygenic scores for ADHD (ADHD-PGS) and educational attainment (EA-PGS) were computed from twins' and parents' genotypes. A model of intergenerational transmission was developed to estimate (1) the contributions of parents' and children's PGS to the twins' ADHD symptoms and (2) whether these variances were explained by genetic transmission and/or genetic nurture.

Results

ADHD-PGS explained up to 1.6% of the variance of hyperactivity and inattention in early childhood and primary school. EA-PGS predicted ADHD symptoms at both ages, explaining up to 1.6% of the variance in early childhood and up to 5.5% in primary school. Genetic transmission was the only significant transmission pathway of both PGS. The genetic nurture channeled through EA-PGS explained up to 3.2% of the variance of inattention in primary school but this association was non-significant.

Conclusions

Genetic propensities to ADHD and education predicted ADHD symptoms in childhood, especially in primary school. Its intergenerational transmission was driven primarily by genetic variants passed to the child, rather than by environmentally mediated parental genetic effects. The model developed in this study can be leveraged in future research to investigate genetic transmission and genetic nurture while accounting for parental assortative mating.

Childhood symptoms of attention-deficit/hyperactivity disorder and borderline personality disorder

OBJECTIVE

Childhood attention-deficit /hyperactivity disorder (ADHD) is known to be associated with adult Borderline Personality Disorder (BPD). We investigated if any of the subdimensions of childhood ADHD, that is, impulsivity, inattention, or hyperactivity was more prominent in this association.

METHODS

In a nation-wide cohort (N = 13,330), we utilized parent reported symptoms of childhood ADHD and clinically ascertained adult BPD diagnoses. The summed total scores of ADHD symptoms and its three subdimensions were used and standardized for effect size comparison. Associations were analyzed using Cox regression with sex and birth-year adjustments. Secondary outcomes were BPD-associated traits (i.e., self-harm and substance use) analyzed using logistic- and linear regression respectively.

RESULTS

ADHD symptom severity was positively associated with BPD with a hazard ratio (HR) of 1.47 (95% confidence interval [CI]: 1.22-1.79) per standard deviation increase in total ADHD symptoms. Impulsivity was the most prominent subdimension with the only statistically significant association when analyzed in a model mutually adjusted for all ADHD subdimensions-HR for inattention: 1.15 (95% CI: 0.85-1.55), hyperactivity: 0.94 (95% CI: 0.69-1.26), impulsivity: 1.46 (95% CI: 1.12-1.91). In secondary analyses, weak positive associations were seen between total ADHD symptom score and self-harm and substance use. In analyses by subdimensions of ADHD, associations were weak and most prominent for inattention in the model with self-harm.

CONCLUSION

Childhood ADHD symptoms were associated with subsequent development of BPD diagnosis and appeared to be driven primarily by impulsivity. Our findings are important for understanding the association between childhood symptoms of ADHD and subsequent BPD.

Exploring the Role of Caffeine Use in Adult-ADHD Symptom Severity of US Army Soldiers

There is a growing trend of using energy drinks and caffeinated beverages to improve cognitive performance that is widespread and well-studied among children and teenagers with Attention Deficit Hyperactive Disorder (ADHD), but little is known about adult ADHD (A-ADHD). As a consequence, the use of highly caffeinated drinks and their impact on ADHD symptoms are poorly understood. This is especially true in populations where A-ADHD and the use of these beverages are largely represented, such as in military samples. From the All Army Study (AAS) of the Army Study to Assess Risk and Resilience in Service members (STARRS) data, 1,239 A-ADHD soldiers and 17,674 peers without any psychiatric comorbidity were selected. The two groups were compared on: (1) the presence of substance use disorder (SUD) diagnosis both over their lifetime and in the previous 30 days; (2) patterns of alcohol and caffeine use using chi-square analyses. Lastly, the relationship between substance use and severity of A-ADHD symptoms was assessed using Pearson’s correlations. Soldiers with a diagnosis of A-ADHD had a higher prevalence of SUD diagnosis compared to their peers without psychiatric comorbidity. They also tended to use more alcohol, caffeine pills, energy drinks, and other caffeinated drinks. Alcohol use was positively correlated with A-ADHD symptoms; on the contrary, energy drinks, caffeine pills and other caffeinated drinks showed negative correlations with some aspects of A-ADHD symptomatology. The use of caffeinated compounds appears to be increased among military soldiers with ADHD, and they may help reducing A-ADHD symptoms and improve cognitive performance. These results suggest a possible role for caffeine as a potential pharmacological tool in the treatment of adult ADHD.

The association between general childhood psychopathology and adolescent suicide attempt and self-harm: A prospective, population-based twin study

Few quantitative behavior genetic studies have examined why psychopathology is associated with suicide attempt (SA) and self-harm (SH) in adolescence. The present study analyzed data from the Child and Adolescent Twin Study in Sweden to examine the extent to which genetic and environmental factors explain SA/SH and its association with psychopathology in childhood, an often-cited risk factor of subsequent SA/SH. When children were 9 or 12 years old (n = 30,444), parents completed the Autism-Tics, AD/HD and other Comorbidities Inventory (Larson et al., 2010) regarding their children's psychiatric problems as part of an ongoing, longitudinal study. At age 18 years (n = 10,269), adolescents completed self-report questionnaires, including SA/SH assessments. In a bifactor model of childhood psychopathology, a general factor of psychopathology was a statistically significant predictor of adolescent SA/SH at a higher magnitude (β, 0.25, 95% confidence interval [CI; 0.15, 0.34] for suicide attempt), as compared with specific factors of inattention, impulsivity, oppositional behavior, and anxiety/emotion symptoms. Quantitative genetic modeling indicated that the additive genetic influences on the general factor accounted for the association with each outcome (β, 0.24, 95% CI [0.13, 0.34] for suicide attempt). The results remained virtually identical when we fit a higher order factors model. Two additional outcomes demonstrated comparable results. The results extend current literature by revealing the shared genetic overlap between general psychopathology during childhood and adolescent SA/SH. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Early substance use in the pathway from childhood attention-deficit/hyperactivity disorder (ADHD) to young adult substance use: Evidence of statistical mediation and substance specificity

This study tested whether early and developmentally atypical substance use mediates risk for adult substance use among children with attention-deficit/hyperactivity disorder (ADHD), and whether that risk is substance-specific. Participants were children with ADHD previously enrolled in a randomized controlled trial (RCT), and a demographically similar non-ADHD group, assessed at 2 through 16 years after the original RCT baseline. Self-reports of heavy drinking, marijuana use, daily smoking, and other illicit drug use were collected at follow-ups to establish atypically early and frequent use. Models estimated statistically mediated effects of childhood ADHD on adult substance use via early substance involvement, with planned comparisons to evaluate substance specificity. Results supported the mediation hypothesis, showing that childhood ADHD was associated with more frequent adult substance use via early substance involvement for marijuana, cigarettes, illicit drugs, and to a lesser extent, alcohol. Mediation was not escalated by comorbid childhood conduct disorder or oppositional defiant disorder except for early use of nonmarijuana illicit drugs. Substance-specificity in the mediational pathway was largely absent except for cigarette use, where ADHD-related early smoking most strongly predicted adult daily smoking. Findings from this study provide new evidence that atypically early substance use associated with childhood ADHD signals important cross-drug vulnerability by early adulthood, but cigarette use at a young age is especially associated with increased risk for habitual (daily) smoking specifically. Efforts to prevent, delay, or reduce substance experimentation should occur early and focus on factors relevant to multiple drugs of abuse in this at-risk population. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The association between early life mental health and alcohol use behaviours in adulthood: A systematic review

This systematic review aims to summarise current evidence on the association between early life mental health and alcohol use behaviours in adulthood. Peer-reviewed publications were located by searching EMBASE, Medline, PsycINFO, and the ISI Web of Science up to 31 October 2018. Prospective longitudinal studies reporting associations between externalising problems (EXT), internalising problems (INT), depression, anxiety before age 18, and alcohol use behaviours (alcohol consumption, heavy/problematic drinking, alcohol use disorder) after age 18 were included. After screening 17259 articles, 36 articles met the inclusion criteria. Information extracted included strength of associations, age when mental health and alcohol use behaviours were measured, sex differences in the association, and other sample characteristics. 103 tests in 23 articles were identified on the externalising domain and 135 tests in 26 articles on the internalising domain. 37 out of 103 tests reported positive associations between EXT and alcohol use behaviours. The likelihood of observing positive associations was higher for more severe alcohol use outcomes, but this trend disappeared among high-quality studies. Findings on associations between internalising domain and alcohol use varied across their subtypes. INT tended to be negatively associated with alcohol consumption but positively associated with more severe outcomes (heavy/problematic drinking, alcohol use disorder). Depression tended to be positively associated with alcohol outcomes, while no clear association between anxiety and alcohol outcomes was evident. Variation of the association across developmental timing, sex, culture, historical period was explored where appropriate. Great heterogeneity in the current literature calls for greater attention to view the relationship developmentally.

Problematic Alcohol and Drug Use Is Associated with Low Self-Directedness and Cooperativeness

BACKGROUND

Personality traits, such as self-directedness (SD) and cooperativeness (CO), may be indicative of problematic alcohol and/or drug use.

OBJECTIVES

The aim of this study was to quantify the association of substance use with SD and CO in a large cohort of adolescents.

METHOD

A total of 6,917 individuals (58% women) at the age of 18 who had filled in the Alcohol Use Disorder Identification Test (AUDIT) and Drug Use Disorder Identification Test (DUDIT), and the SD and CO scales from the Temperament and Character -Inventory, as part of the Child and Adolescent Twin study in Sweden were included in the analyses.

RESULTS

High AUDIT scores (>15) were found in 2.4% of the population and high DUDIT scores (>7) in 1.2% of the population. Total score on the AUDIT was negatively correlated (p < 0.001) with SD (r = -0.18) and CO (r = -0.15), as well as total DUDIT with SD (r = -0.11) and CO (r = -0.08). The risk of high AUDIT (>15) and DUDIT (>7) was highest for those with a low (1 standard deviation below mean) SD score (ORs 4.1 and 4.5, p < 0.001) and a low CO score (ORs 3.5 and 4.5, p < 0.001). However, at 1 standard deviation above mean, no association between alcohol or drug use and SD or CO was seen. Using SD and CO scores to predict AUDIT >15 or DUDIT >7 yielded a sensitivity between 62.4 and 71.3% and a specificity between 64.9 and 70.4%.

CONCLUSIONS

Personality traits of low SD and CO are associated with increased alcohol and drug use. These findings support the notion that personality traits can be used to identify individuals at high risk of substance abuse.

The nature and nurture of ADHD and its comorbidities: A narrative review on twin studies

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in children worldwide, and also the recognition of its persistence into adulthood is increasing. While ADHD in childhood is highly heritable and mostly driven by familial factors, during adulthood it appears to show a lower heritability, even if there is not total agreement on this yet. This disorder often co-occurs with many other conditions, which also vary across the different stages of development, and several studies have used the twin design to investigate these comorbidities, giving valuable insights into the origins of the observed co-occurrence. This review aims to summarize the main results of twin research, according to the following domains: individual traits, cognitive impairment, behavioral manifestations, clinical conditions and psychosocial risk factors. Individual features seem to play a role in this symptomatology and include personality traits such as negative emotionality, personality disorders and temperamental dimensions with a predominance of novelty seeking. At a lower level, ADHD is associated with both functional and anatomic brain characteristics. ADHD is also associated with some forms of cognitive impairment, such as sluggish cognitive tempo, and learning disabilities, with a specific predisposition to reading disability. In addition, ADHD is strongly associated with externalizing disorders such as conduct disorder and oppositional defiant disorder, and some behavioral outcomes, particularly substance use and abuse both in adolescence and adulthood. Moreover, ADHD symptoms often overlap with other psychological disorders, namely affective and internalizing disorders, as well as autism spectrum disorder and autistic-like traits in a wider sense. Notably, a genetic overlap has been found between asthma and ADHD, particularly with respect to hyperactivity/impulsivity dimensions. ADHD also appears to represent a risk factor for disordered eating, and, more specifically, for binge eating and bulimia nervosa. Finally, among psychosocial factors, an association has been proposed between childhood maltreatment and ADHD symptoms.

Risk of Alcohol Abuse in Humans with Attention-deficit/Hyperactivity Disorder Symptoms

The relationship between attention-deficit/hyperactivity disorder (ADHD) and the risk of alcohol abuse is widely studied. Even though this topic has been of interest for several years, it is heavily debated. We studied various papers and conducted a systematic review using PubMed as the main source of data collection. We found that several studies put forward the concept of a positive association between alcohol abuse and ADHD symptoms, but a minority of them also showed opposing and contradictory results. We discovered that this inconsistency observed in studies could be a result of a biased approach in studies and a subjective attempt in interpretations. These biases could be studied in terms of sample size involved in the analysis, age at which studies are conducted among other statistical parameters. We believe that the deviations in the outcomes prove that the studies may be incomplete and that a standardized method of interpretation is required. Therefore, this paper recommends the need for further research to explore the connection between alcohol abuse in patients showing ADHD symptoms.

Psychiatric Disorders After Attention-Deficit/Hyperactivity Disorder: A Nationwide Population-Based Study in Taiwan

PURPOSE

To investigate the risk for psychiatric disorders in patients newly diagnosed with attention deficit hyperactive disorder (ADHD) from two longitudinal groups of children with and without ADHD.

STUDY DESIGN

In total, 1,745 children newly diagnosed with ADHD and 6,980 participants without ADHD were identified from Taiwan's National Health Insurance Research Database in 2005 and followed until 2010. Risks for psychiatric disorders in the ADHD and non-ADHD groups were compared.

RESULTS

The ADHD group was 3.82 times more likely to develop psychiatric disorders than their counterparts. The ADHD group showed the highest risk for oppositional defiant disorder, followed by adult ADHD and autism spectrum disorder. Moreover, the time effects of psychiatric disorders in the ADHD group were significant. Patients with ADHD subtypes had a significant risk for psychiatric disorders compared to their counterparts.

CONCLUSIONS

A high risk for psychiatric disorders was revealed in this study among children with ADHD. Childhood ADHD, the duration after the ADHD diagnosis, and the ADHD subtype were associated with psychiatric disorders.

CLINICAL RELEVANCE

Various psychiatric disorders were observed in children after they had been newly diagnosed with ADHD, indicating a need for integrated care that includes medical practitioners, family members, social workers, and early intervention workers for patients newly diagnosed with ADHD to decrease the risk for comprehensive psychiatric disorders.

Childhood neurodevelopmental disorders and risk of coercive sexual victimization in childhood and adolescence - a population-based prospective twin study

BACKGROUND

Autism spectrum disorder (ASD), Attention-deficit/Hyperactivity disorder (ADHD), and other related neurodevelopmental disorders (NDDs) have, in some previous studies, been shown to increase the risk of being sexually victimized. However, no studies have examined whether the association is driven by a general NDD phenotype versus specific diagnoses, nor the etiology of the association.

METHOD

Using a genetically informative, prospective design, we examined the association between ASD and ADHD in childhood and coercive sexual victimization up to age 18. A total of 4,500 children participating in the Child and Adolescent Twin Study in Sweden (CATSS) were rated by their parents on NDDs at age 9 or 12 years, and self-reported at age 18 on lifetime experiences of coercive sexual touching and/or coercive sex. First, we regressed sexual victimization on the NDDs. Second, we regressed sexual victimization on general and specific NDD symptoms identified via a bifactor model. Third, we decomposed the observed associations into genetic and environmental parts.

RESULTS

In females, ASD was associated with an almost threefolded increased risk of coercive sexual victimization, and ADHD with a doubled risk. In males, the risk associated with ASD and ADHD was of the same magnitude but not significant. When controlling for overall NDD symptom load ASD or ADHD, no longer uniquely predicted coercive sexual victimization. The association between the NDD general factor and coercive sexual victimization was due to shared genetics.

CONCLUSIONS

General NDD symptom load, rather than specific ASD or ADHD symptoms, seems to be a moderate vulnerability factor for coercive sexual victimization. We speculate that an evocative gene-environment correlation might account for this observation, such that sexual perpetrators actively target NDD individuals.

Associations between childhood ADHD, gender, and adolescent alcohol and marijuana involvement: A causally informative design

BACKGROUND

We report whether the etiology underlying associations of childhood ADHD with adolescent alcohol and marijuana involvement is consistent with causal relationships or shared predispositions, and whether it differs by gender.

METHODS

In three population-based twin samples (N = 3762; 64% monozygotic), including one oversampling females with ADHD, regressions were conducted with childhood inattentive or hyperactive-impulsive symptoms predicting alcohol and marijuana outcomes by age 17. To determine whether ADHD effects were consistent with causality, twin difference analyses divided effects into those shared between twins in the pair and those differing within pairs.

RESULTS

Adolescents with more severe childhood ADHD were more likely to initiate alcohol and marijuana use earlier, escalate to frequent or heavy use, and develop symptoms. While risks were similar across genders, females with more hyperactivity-impulsivity had higher alcohol consumption and progressed further toward daily marijuana use than did males. Monozygotic twins with more severe ADHD than their co-twins did not differ significantly on alcohol or marijuana outcomes, however, suggesting a non-causal relationship. When co-occurring use of other substances and conduct/oppositional defiant disorders were considered, hyperactivity-impulsivity remained significantly associated with both substances, as did inattention with marijuana, but not alcohol.

CONCLUSIONS

Childhood ADHD predicts when alcohol and marijuana use are initiated and how quickly use escalates. Shared familial environment and genetics, rather than causal influences, primarily account for these associations. Stronger relationships between hyperactivity-impulsivity and heavy drinking/frequent marijuana use among adolescent females than males, as well as the greater salience of inattention for marijuana, merit further investigation.

ADHD Medication and Substance-Related Problems

OBJECTIVE

Substance use disorders are major contributors to excess mortality among individuals with attention deficit hyperactivity disorder (ADHD), yet associations between pharmacological ADHD treatment and substance-related problems remain unclear. This study investigated concurrent and long-term associations between ADHD medication treatment and substance-related events.

METHOD

The authors analyzed 2005-2014 commercial health care claims from 2,993,887 (47.2% female) adolescent and adult ADHD patients. Within-individual analyses compared the risk of substance-related events (i.e., emergency department visits related to substance use disorders) during months in which patients received prescribed stimulant medication or atomoxetine relative to the risk during months in which they did not.

RESULTS

In adjusted within-individual comparisons, relative to periods in which patients did not receive ADHD medication, male patients had 35% lower odds of concurrent substance-related events when receiving medication (odds ratio=0.65, 95% CI=0.64-0.67), and female patients had 31% lower odds of concurrent substance-related events (odds ratio=0.69, 95% CI=0.67-0.71). Moreover, male patients had 19% lower odds of substance-related events 2 years after medication periods (odds ratio=0.81, 95% CI=0.78-0.85), and female patients had 14% lower odds of substance-related events 2 years after medication periods (odds ratio=0.86, 95% CI= 0.82-0.91). Sensitivity analyses supported most findings but were less consistent for long-term associations among women.

CONCLUSIONS

These results provide evidence that receiving ADHD medication is unlikely to be associated with greater risk of substance-related problems in adolescence or adulthood. Rather, medication was associated with lower concurrent risk of substance-related events and, at least among men, lower long-term risk of future substance-related events.

Reward-related ventral striatum activity links polygenic risk for attention-deficit/hyperactivity disorder to problematic alcohol use in young adulthood

BACKGROUND

Problematic alcohol use in adolescence and adulthood is a common and often debilitating correlate of childhood attention-deficit/hyperactivity disorder (ADHD). Converging evidence suggests that ADHD and problematic alcohol use share a common additive genetic basis, which may be mechanistically related to reward-related brain function. In the current study, we examined whether polygenic risk for childhood ADHD is linked to problematic alcohol use in young adulthood through alterations in reward-related activity of the ventral striatum, a neural hub supporting appetitive behaviors and reinforcement learning.

METHODS

Genomic, neuroimaging, and self-report data were available for 404 non-Hispanic European-American participants who completed the ongoing Duke Neurogenetics Study. Polygenic risk scores for childhood ADHD were calculated based on a genome-wide association study meta-analysis conducted by the Psychiatric Genomics Consortium and tested for association with reward-related ventral striatum activity, measured using a number-guessing functional magnetic resonance imaging paradigm, and self-reported problematic alcohol use. A mediational model tested whether ventral striatum activity indirectly links polygenic risk for ADHD to problematic alcohol use.

RESULTS

Despite having no main effect on problematic alcohol use, polygenic risk for childhood ADHD was indirectly associated with problematic alcohol use through increased reward-related ventral striatum activity.

CONCLUSIONS

Individual differences in reward-related brain function may, at least in part, mechanistically link polygenic risk for childhood ADHD to problematic alcohol use.