Gender and injuries predict stimulant medication use

Sex differences in attention-deficit hyperactivity disorder diagnosis and clinical care: a national study of population healthcare records in Wales

BACKGROUND

Population-based studies have observed sex biases in the diagnosis and treatment of attention-deficit hyperactivity disorder (ADHD). Females are less likely to be diagnosed or prescribed ADHD medication. This study uses national healthcare records, to investigate sex differences in diagnosis and clinical care in young people with ADHD, particularly regarding recognition and treatment of other mental health conditions.

METHODS

The cohort included individuals diagnosed with ADHD, born between 1989 and 2013 and living in Wales between 2000 and 2019. Routine primary and secondary healthcare record data were used to derive diagnoses of ADHD and other neurodevelopmental and mental health conditions, as well as ADHD and antidepressant medications. Demographic variables included ethnicity, socioeconomic deprivation and contact with social services.

RESULTS

There were 16,458 individuals diagnosed with ADHD (20.3% females, ages 3-30 years), with a male-to-female ratio of 3.9:1. Higher ratios (4.8:1) were seen in individuals diagnosed younger (<12 years), with the lowest ratio (1.9:1) in those diagnosed as adults (>18). Males were younger at first recorded ADHD diagnosis (mean = 10.9 vs. 12.6 years), more likely to be prescribed ADHD medication and younger at diagnosis of co-occurring neurodevelopmental conditions. In contrast, females were more likely to receive a diagnosis of anxiety, depression or another mental health condition and to be prescribed antidepressant medications, prior to ADHD diagnosis. These sex differences were largely stable across demographic groups.

CONCLUSIONS

This study adds to the evidence base that females with ADHD are experiencing later recognition and treatment of ADHD. The results indicate that this may be partly because of diagnostic overshadowing from other mental health conditions, such as anxiety and depression, or initial misdiagnosis. Further research and dissemination of findings to the public are needed to improve awareness, timely diagnosis and treatment of ADHD in females.

Why are females less likely to be diagnosed with ADHD in childhood than males?

ADHD is less likely to be diagnosed in females than males, especially in childhood. Females also typically receive the diagnosis later than males and are less likely to be prescribed ADHD medication. Understanding why these sex differences in clinical care and treatment for ADHD occur is key to improving timely diagnosis in people affected by ADHD. This Personal View is a conceptual review synthesising literature on this topic. This publication considers potential biological explanations (eg, genetic factors), influence of diagnostic practices (eg, criteria suitability, diagnostic overshadowing, and sex-specific diagnostic thresholds), and sociocultural explanations (eg, sex differences in presentation and compensatory behaviours), for the observed sex differences in ADHD clinical practice. This Personal View also outlines future research directions for improving understanding of sex differences in recognition and diagnosis of ADHD.

Family and developmental history of female versus male adolescents with ADHD: diagnosis-specific overlap, few gender/sex differences

Background

Gender and sex differences in the development of children and adolescents are commonly found in the psychiatric examination. Family and developmental history is an important part of the clinical diagnostic interview, the basic examination technique. Attention-deficit/hyperactivity disorder (ADHD) is associated with diagnosis-specific markers in family and development history. However, it is unclear to what extent ADHD-specific signs and narratives differ between females and males. The aim of this study was to assess and to compare the family and developmental history profiles of female versus male adolescents with ADHD.

Methods

Data were collected using the clinical diagnostic interview technique from parents of female and male patients diagnosed with ADHD (ICD-10  F90.0, F90.1 and F98.8) between the ages of 12 and 17  years (n = 92). The two groups were matched in pairs for sex, IQ and ICD-10 diagnosis (F90.0, F90.1 and F98.8). Interview data were operationalized in three categories: 0 - physiological marker, 1 - subclinical marker, 2 - clinical marker. The two groups were compared with two-way ANOVA.

Results

Information about female in comparison to male adolescents were reported in the parental interview with few differences.

Conclusion

Our study suggests that family and developmental history of the neurodevelopmental disorder ADHD is only poorly influenced by gender or sex.

Gender Trends in Psychotropic Medication Use in Autism

Autism is a neurodevelopmental condition that includes differences in social communication and restrictive, repetitive behavior. Its diagnosis is far more common in men than women. Therefore, a female phenotype of autism might not concern caregivers or be detected early by clinical assessments. Given that medications address problematic behaviors rather than autism, different problems associated with autism necessitate other treatments. We reviewed existing literature on gender differences in psychotropic drug usage in autism patients and found that antidepressants, anticonvulsants, and mood stabilizers were more common in females, while stimulants and antipsychotics were predominant in males. This review highlights that autistic men and women receive different pharmacologic agents, likely attributable to gender-specific trends in presenting problematic behaviors.

Understanding the Diversity of Pharmacotherapeutic Management of ADHD With Co-occurring Autism: An Australian Cross-Sectional Survey

OBJECTIVES

Attention deficit hyperactivity disorder (ADHD) frequently co-occurs with other neurodevelopmental diagnoses, such as autism spectrum disorder (autism), which can make clinical decision making around symptom management challenging for clinicians. There is a paucity of research examining pharmacotherapeutic management of children who have ADHD with co-occurring diagnoses. We aimed to report on the co-occurring diagnoses and symptom profile of children, and report on medication use, stratified by ADHD, autism and ADHD + autism diagnoses.

METHODS AND MATERIALS

Caregivers of 505 children (2-18 years) with ADHD (n = 239), autism (n = 117), and co-occurring ADHD + autism (n = 149) completed a questionnaire on current medication use and clinical rating scales about their child's symptoms, as part of a broader project investigating diagnosis and management of symptoms in children with ADHD or autism.

RESULTS

The parents of the ADHD group reported a higher proportion of their children had learning disorders (17.15%) and speech and language disorders (4.60%) compared to the parents of the autism and ADHD + autism groups. Parents of the ADHD + autism group reported higher proportions of intellectual disability (5.37%), oppositional defiant disorder (20.13%), anxiety (38.93%), depression (6.71%) and genetic conditions (3.36%) in their children, in comparison to the parents of the ADHD and autism groups. Children with ADHD were reported to be taking a higher proportion of psychotropic medication (90%), followed by ADHD + autism (86%) and autism (39%). The parents of children with ADHD + autism reported a higher proportion of non-stimulant ADHD medication (25.5%), antipsychotic (18.79%), antidepressant (22.15%) and melatonin (31.54%) use by their children, compared to the parents of the ADHD and autism groups.

CONCLUSIONS

A similar proportion of children with ADHD + autism and ADHD were reported to be taking medication. However, the types of medication taken were different, as expected with reported co-occurring diagnoses. The complexity of symptoms and diagnoses in ADHD + autism warrants targeted research to optimize management and therapeutic outcomes.

Time of onset and/or diagnosis of ADHD in European children: a systematic review

BACKGROUND

Attention-Deficit/ Hyperactivity Disorder (ADHD) is one of the most common childhood neurobehavioral conditions. Symptoms related to this disorder cause a significant impairment in school tasks and in the activities of children's daily lives; an early diagnosis and appropriate treatment could almost certainly help improve their outcomes. The current study, part of the Models Of Child Health Appraised (MOCHA) project, aims to explore the age at which children experience the onset or diagnosis of ADHD in European countries.

METHODS

A systematic review was done examining the studies reporting the age of onset/diagnosis (AO/AD) of ADHD in European countries (28 European Member States plus 2 European Economic Area countries), published between January 1, 2010 and December 31, 2019. Of the 2276 identified studies, 44 met all the predefined criteria and were included in the review.

RESULTS

The lowest mean AO in the children diagnosed with ADHD alone was 2.25 years and the highest was 7.5 years. It was 15.3 years in the children with ADHD and disruptive behaviour disorder. The mean AD ranges between 6.2 and 18.1 years.

CONCLUSIONS

Our findings indicate that there is a wide variability in both the AO and AD of ADHD, and a too large distance between AO and AD. Since studies in the literature suggest that an early identification of ADHD symptoms may facilitate early referral and treatment, it would be important to understand the underlying reasons behind the wide variability found.

TRIAL REGISTRATION

PROSPERO registration: CRD42017070631 .

Pediatric use of prescribed melatonin in Sweden 2006-2017: a register based study

Sleep disturbances are common in the pediatric population and should primarily be treated non-pharmacologically. Most medicines for sleep disturbances are not approved for pediatric use and data on long-term safety is scarce. In Sweden, melatonin is classified as a prescription medicine. The aim of the present study was to characterize the prevalence and incidence of dispensed melatonin prescriptions, long-term treatment, concomitant dispensation of psychotropic medication, and psychiatric comorbidity, in children and adolescents aged 0-17 years living in Sweden during 2006-2017. Data was retrieved by linking the national population-based registers, the Swedish Prescribed Drug register and the National Patient register. In 2017, nearly 2% of the pediatric population 0-17 years was dispensed at least one prescription of melatonin, which was more than a 15-fold increase for girls and a 20-fold increase for boys, when compared to 2006. Among the children in the age group 5-9 who initiated a melatonin treatment in 2009, 15% of girls and 17% of boys were found to be continuously prescribed melatonin 8 years later. Nearly 80% of all children with dispensed melatonin had concomitant dispensations of psychotropic medications. The most common combination was melatonin together with centrally acting sympathomimetic medicines (23% of girls and 43% of boys). About half of the children (47% of girls and 50% of boys) had at least one registered diagnosis of mental or behavioral disorders. The most common diagnosis was attention deficit hyperactive disorder, across all age groups and genders. The continuous increase of use of melatonin in children, often concomitant with other psychotropic medications, together with a high proportion of younger children with prescriptions of melatonin on a long-term basis, suggests the need for further structured follow up studies, in particular of long-term use.

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.

Females with ADHD: An expert consensus statement taking a lifespan approach providing guidance for the identification and treatment of attention-deficit/ hyperactivity disorder in girls and women

BACKGROUND

There is evidence to suggest that the broad discrepancy in the ratio of males to females with diagnosed ADHD is due, at least in part, to lack of recognition and/or referral bias in females. Studies suggest that females with ADHD present with differences in their profile of symptoms, comorbidity and associated functioning compared with males. This consensus aims to provide a better understanding of females with ADHD in order to improve recognition and referral. Comprehensive assessment and appropriate treatment is hoped to enhance longer-term clinical outcomes and patient wellbeing for females with ADHD.

METHODS

The United Kingdom ADHD Partnership hosted a meeting of experts to discuss symptom presentation, triggers for referral, assessment, treatment and multi-agency liaison for females with ADHD across the lifespan.

RESULTS

A consensus was reached offering practical guidance to support medical and mental health practitioners working with females with ADHD. The potential challenges of working with this patient group were identified, as well as specific barriers that may hinder recognition. These included symptomatic differences, gender biases, comorbidities and the compensatory strategies that may mask or overshadow underlying symptoms of ADHD. Furthermore, we determined the broader needs of these patients and considered how multi-agency liaison may provide the support to meet them.

CONCLUSIONS

This practical approach based upon expert consensus will inform effective identification, treatment and support of girls and women with ADHD. It is important to move away from the prevalent perspective that ADHD is a behavioural disorder and attend to the more subtle and/or internalised presentation that is common in females. It is essential to adopt a lifespan model of care to support the complex transitions experienced by females that occur in parallel to change in clinical presentation and social circumstances. Treatment with pharmacological and psychological interventions is expected to have a positive impact leading to increased productivity, decreased resource utilization and most importantly, improved long-term outcomes for girls and women.

Risk of Dementia in Adults With ADHD: A Nationwide, Population-Based Cohort Study in Taiwan

OBJECTIVE

This study aimed to investigate the association between adults with ADHD and the risk of developing dementia.

METHOD

Utilizing National Health Insurance Research Database of Taiwan, ADHD patients were identified and compared with age- and gender-matched controls (1:3).

RESULTS

Of the study participants, 37 (5.48%) developed dementia compared with 81 (4.0%) in the control group. Cox proportional hazards regression analysis revealed that the study participants were more likely to develop dementia. The crude hazard ratio (HR) is 3.418 (95% confidence interval [CI] = [2.289, 5.106], p < .001), and adjusted HR is 4.008 (95% CI = [2.526, 6.361], p < .001) in risk of developing dementia after adjusted for age, gender, comorbidities, geographical area of residence, urbanization level of residence, and monthly income.

CONCLUSION

Adults with ADHD have a 3.4-fold risk of developing dementia, and other large or national data sets should be explored to support the current findings.

Sex Differences in Comorbidity Patterns of Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To investigate sex differences in associations between attention-deficit/hyperactivity disorder (ADHD) and a spectrum of comorbid disorders.

METHOD

The study population included all children born in Denmark from 1981 through 2013 (N = 1,665,729). Data were merged from Danish registers and information was obtained on birth characteristics, socioeconomic status, familial psychiatric history, and diagnoses of ADHD (n = 32,308) and comorbid disorders. To estimate absolute and relative risks of comorbid disorders, incidence rates and adjusted hazard ratios (HRs) with 95% CIs were calculated for female and male individuals. In addition, interactions between ADHD and sex in association with comorbid disorders were estimated as HR ratios (HRRs) in female and male individuals (95% CIs).

RESULTS

Individuals diagnosed with ADHD had significantly increased absolute and relative risks of all 12 comorbid psychiatric disorders investigated. ADHD-sex interactions were found for some comorbid disorders. Compared with male individuals, ADHD in female individuals showed a stronger association with autism spectrum disorder (HRR 1.86, 95% CI 1.62-2.14), oppositional defiant/conduct disorder (HRR 1.97, 95% CI 1.68-2.30), intellectual disability (HRR 1.79, 95% CI 1.54-2.09), personality disorders (HRR 1.23, 95% CI 1.06-1.43), schizophrenia (HRR 1.21, 95% CI 1.02-1.43), substance use disorders (HRR 1.21, 95% CI 1.07-1.38), and suicidal behavior (1.28, 95% CI 1.12-1.47). The remaining disorders showed no significant sex differences in association with ADHD.

CONCLUSION

This study indicates that the association between ADHD and several comorbid disorders is stronger in female than in male individuals. These important findings add to the literature on sex differences in ADHD and suggest that female individuals diagnosed with ADHD are a more vulnerable group of patients.

Risk of unintentional injuries in children and adolescents with ADHD and the impact of ADHD medications: protocol for a systematic review and meta-analysis

INTRODUCTION

Attention-deficit hyperactivity disorder (ADHD) has been related to increased rates of unintentional injuries. However, the magnitude of the effect and to which extent variables such as sex, age or comorbidity can influence this relationship is unknown. Additionally, and importantly, it is unclear if, and to which degree, ADHD medications can decrease the number of unintentional injuries. Due to the amount of economic and social resources invested in the treatment of injuries, filling these gaps in the literature is highly relevant from a public health standpoint. Here, we present a protocol for a systematic review and meta-analysis to estimate the relationship between ADHD and unintentional injuries and assess the impact of pharmacological treatment for ADHD METHODS AND ANALYSIS: We will combine results from 114 bibliographic databases for studies relating ADHD and risk of injuries. Bibliographic searches and data extraction will be carried out independently by two researchers. The studies' risk of bias will be assessed using the Newcastle-Ottawa Scale. Articles reporting ORs or HRs of suffering an injury in ADHD compared with controls (or enough data to calculate them) will be combined using Robust Variance Estimation, a method that permits to include multiple non-independent outcomes in the analysis. All analyses will be carried out in Stata. Age, sex and comorbid conduct disorders will be considered as potential causes of variance and their effect analysed through meta-regression and subgroup analysis. Sensitivity analyses will exclude articles with longer follow-ups, non-stringent definitions of ADHD or controls and statistically uncontrolled/controlled outcomes. Studies implementing a self-controlled case series methodology to investigate if ADHD drugs reduce the risk of injuries will be combined with a generalised linear mixed model using the Poisson distribution and a log link function.

REGISTRATION DETAILS

PROSPERO-Prospective Register of Systematic Reviews (CRD42017064967).

The risk of injury in adults with attention-deficit hyperactivity disorder: A nationwide, matched-cohort, population-based study in Taiwan

BACKGROUND

Few studies have investigated the risk of injuries associated with adults with attention-deficit hyperactivity disorder (ADHD), even though several studies have suggested a higher risk of injury in children and adolescents with ADHD.

AIMS

To investigate the risk of injury in adults with ADHD.

METHODS AND PROCEDURES

We included 665 adults with ADHD from January 1, to December 31, 2000, and 1995 sex-, age- and index day-matched controls without ADHD from the Longitudinal Health Insurance Database (LHID) subset of the National Health Insurance Research Database in Taiwan. The Cox proportional hazard models were used to analyze the associations between the relevant demographics, and the psychiatric comorbidities and the risk of injury.

OUTCOMES AND RESULTS

The patients with ADHD had a 143% increased risk of overall injuries than the controls after considering all the confounding factors. In addition, the use of methylphenidate was associated with a 22.6% decrease in the risk of injuries in the patients with ADHD.

CONCLUSIONS AND IMPLICATIONS

Our findings strongly support that adults with ADHD are at an increased risk of injury, and imply that methylphenidate therapy may attenuate this risk.

Trends in Off-Label Prescribing of Sedatives, Hypnotics and Antidepressants among Children and Adolescents - A Danish, Nationwide Register-Based Study

In recent years, psychotropic drug use among children and adolescents in Europe and USA has increased. However, the majority of psychotropic drugs are not formally approved for use in children and adolescents, and consequently, use is often off-label. The objectives were to describe time trends in off-label prescribing rates and the most commonly used types of psychotropic drugs by age and gender in Danish children and adolescents. Using the Register of Medicinal Product Statistics, we identified all prescriptions for sedatives, hypnotics and antidepressants filled for children and adolescents in 2006-2012. Information on diagnoses was obtained from the Danish National Registry of Patients and allowed classification of prescriptions as either on- or off-label. We identified 186,831 prescriptions filled for 29,851 children and adolescents: 88.0% of these were classified as off-label. During 2006-2012, off-label rates for sedatives and hypnotics increased significantly, except for prescriptions for girls aged 15-17 years [range 24.1-98.2% (girls), 31.9% to 99.0% (boys)]. In the same period, the number of registered melatonin prescriptions (all off-label) increased expansively. For antidepressants, we found decreasing trends in off-label rates over time [range 94.5-65.6% (girls), 93.8-71.2% (boys)]. Off-label prescribing of psychotropic drugs to Danish children and adolescents is common. Off-label rates for sedatives and hypnotics increased in the period of 2006-2012, whereas off-label rates for antidepressants declined. Off-label rates might be underestimated and should be considered a conservative estimate.

Problematic Peer Functioning in Girls with ADHD: A Systematic Literature Review

Objective

Children with attention deficit hyperactivity disorder (ADHD) experience many peer interaction problems and are at risk of peer rejection and victimisation. Although many studies have investigated problematic peer functioning in children with ADHD, this research has predominantly focused on boys and studies investigating girls are scant. Those studies that did examine girls, often used a male comparison sample, disregarding the inherent gender differences between girls and boys. Previous studies have highlighted this limitation and recommended the need for comparisons between ADHD females and typical females, in order to elucidate the picture of female ADHD with regards to problematic peer functioning. The aim of this literature review was to gain insight into peer functioning difficulties in school-aged girls with ADHD.

Methods

PsychINFO, PubMed, and Web of Knowledge were searched for relevant literature comparing school-aged girls with ADHD to typically developing girls (TDs) in relation to peer functioning. The peer relationship domains were grouped into ‘friendship’, ‘peer status’, ‘social skills/competence’, and ‘peer victimisation and bullying’. In total, thirteen studies were included in the review.

Results

All of the thirteen studies included reported that girls with ADHD, compared to TD girls, demonstrated increased difficulties in the domains of friendship, peer interaction, social skills and functioning, peer victimization and externalising behaviour. Studies consistently showed small to medium effects for lower rates of friendship participation and stability in girls with ADHD relative to TD girls. Higher levels of peer rejection with small to large effect sizes were reported in all studies, which were predicted by girls’ conduct problems. Peer rejection in turn predicted poor social adjustment and a host of problem behaviours. Very high levels of peer victimisation were present in girls with ADHD with large effect sizes. Further, very high levels of social impairment and social skills deficits, with large effect sizes, were found across all studies. Levels of pro-social behaviour varied across studies, but were mostly lower in girls with ADHD, with small to large effect sizes. Overall, social disability was significantly higher among girls with ADHD than among TD girls.

Conclusion

Congruous evidence was found for peer functioning difficulties in the peer relationship domains of friendship, peer status, social skills/competence, and peer victimisation and bullying in girls with ADHD.

The validity and reliability of the diagnosis of hyperkinetic disorders in the Danish Psychiatric Central Research Registry

OBJECTIVE

To validate the diagnosis of hyperkinetic disorders (HD) in the Danish Psychiatric Central Research Registry (DPCRR) for children and adolescents aged 4 to 15 given in the years 1995 to 2005.

METHOD

From a total of 4568 participants, a representative random subsample of n=387 patients were used to validate the diagnosis. Patient files were systematically scored for the presence of ICD-10 criteria for HD and oppositional defiant disorder/conduct disorder (ODD/CD; F91). Further to this, an inter-rater reliability study was also conducted, whereby two experienced child and adolescent psychiatrists who were blind to patients discharge diagnoses, rated a random subsample of n=101 participants.

RESULTS

Information was available for 372 out of 387 patients. Out of n=372 available files, n=324 (86.8%) were evaluated to fulfil diagnostic criteria for HD. Due to missing information it was not possible to reach a conclusion for 5.1% of the cases, 3.8% of the diagnoses were registration errors, and in 4.3% of the files the diagnosis had to be rejected. Inter-rater agreement was high (κ=0.83, z=10.9, P<.001). The validity of hyperkinetic disorders, unspecified (F90.9) was lower and comorbid CD/ODD were under-diagnosed in the sample. All participants fulfilling HD criteria also fulfilled DSM-5-criteria for ADHD.

CONCLUSION

The risk of misclassification of patients with HD in the DPCRR is relatively low, with the exception of the diagnosis of hyperkinetic disorders, unspecified (F90.9).

Gender Differences in Associations Between Attention-Deficit/Hyperactivity Disorder and Substance Use Disorder

OBJECTIVE

To examine gender differences in the association between attention-deficit/hyperactivity disorder (ADHD) and substance use disorder (SUD), and to explore the impact of comorbid psychiatric conditions.

METHOD

This was a cohort study of all children born in Denmark in 1990 to 2003 (n = 729,560). By record linkage across nationwide registers, we merged data on birth characteristics, socioeconomic status, familial psychiatric history, and diagnoses of ADHD (N = 19,645), comorbidities, and SUD. Hazard ratios (HR) with 95% CIs were estimated by Cox regression and adjusted for a range of variables.

RESULTS

ADHD increased the risk of alcohol abuse (HRfemales = 1.72 [95% CI = 1.42-2.08], HRmales = 1.57 [1.37-1.79]), cannabis abuse (HRfemales = 2.72 [2.12-3.47], HRmales = 2.24 [1.86-2.70]), and other illicit substance abuse (HRfemales = 2.05 [1.54-2.73], HRmales = 2.42 [1.98-2.96]), compared to individuals without ADHD. In the overall estimates, no gender differences were found. Among individuals with ADHD without comorbidities, females had a higher SUD risk than males, as did females with ADHD and conduct disorder (CD). Comorbid CD, depression, bipolar disorder, and schizophrenia further increased the risk of SUD in ADHD, compared to non-ADHD. Autism spectrum disorder in males with ADHD lowered the SUD risk.

CONCLUSION

ADHD increased the risk of all SUD outcomes. Individuals with ADHD without comorbidities were also at increased risk, and some comorbid disorders further increased the risk. Females and males with ADHD had comparable risks of SUD, although females had higher risk of some SUDs than males. Females with ADHD may be perceived as less impaired than males, but they are at equally increased risk of SUD.

Diversion of ADHD Stimulants and Victimization Among Adolescents

OBJECTIVE

To examine whether a recent prescription for stimulant medication is associated with peer victimization among youth with attention deficit/hyperactivity disorder (ADHD).

METHODS

Data from 4,965 adolescents attending five public schools who completed an annual web survey over 4 years were used to examine recent stimulant medication prescription and self-reported frequent victimization.

RESULTS

Adolescents with ADHD and recent stimulant prescription reported more victimization than those without ADHD, but similar to adolescents with ADHD and no recent prescription. Adolescents with ADHD and past 12-month diversion of their prescribed stimulants were at greatest risk of 12-month frequent victimization compared with adolescents without ADHD and adolescents with ADHD but no recent prescription. Youth approached to divert reported more victimization than youth not approached. Youth who diverted reported more victimization than those who did not divert.

CONCLUSIONS

Close parent-prescriber collaboration is needed to ensure effective medical treatment for ADHD without greater risk for victimization and treatment failure.

Effect of drugs on the risk of injuries in children with attention deficit hyperactivity disorder: a prospective cohort study

BACKGROUND

Injuries represent the largest disease burden and most common cause of death in children. Attention deficit hyperactivity disorder (ADHD) is associated with increased mortality, with accidents being the most common cause of death in ADHD. However, it is not known whether pharmacological treatment has any modifying effect on the risk of injuries in children and adolescents with ADHD.

METHODS

Using Danish national registers, we followed a cohort of 710 120 individuals, including 4557 individuals diagnosed with ADHD before age 10 years. Using a quasi-experimental, difference-in-difference design, we estimated the odds ratios (ORs) for injuries and the mean change in prevalence rates of injuries and emergency ward visits before and after treatment, with matched untreated children with ADHD at the same age serving as controls.

FINDINGS

Children with ADHD were more likely to sustain injuries, compared with children without ADHD, at age 10 years (adjusted OR=1·29, 95% CI 1·22-1·37) and at age 12 years (adjusted OR=1·30, 1·23-1·37). From age 5 to 10 years, the prevalence of injuries in children with ADHD who were treated with ADHD drugs decreased from 19% to 14%, compared with a prevalence of about 17% in non-treated children with ADHD. This corresponded to an adjusted difference-in-difference reduction in prevalence of injuries at age 10 years of 31·5% (8·2-54·8) and 43·5% (18·1-69·0) at age 12 years due to treatment. Pharmacological treatment also reduced the prevalence of emergency ward visits at age 10 years (28·2%, 6·3-50·1) and age 12 years (45·7%, 25·8-65·7).

INTERPRETATION

Children with ADHD had an increased risk of injuries compared with other children. Treatment with ADHD drugs reduced the risk of injuries by up to 43% and emergency ward visits by up to 45% in children with ADHD. Taken together with previous findings of accidents being the most common cause of death in individuals with ADHD, these results are of major public health importance.

FUNDING

The Lundbeck Foundation, the Danish Council for Independent Research, Centre For Integrated Register-based Research at Aarhus University, the Region of Southern Denmark Research Foundation, and Wørzner's Foundation.

Mortality in children, adolescents, and adults with attention deficit hyperactivity disorder: a nationwide cohort study

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a common mental disorder associated with factors that are likely to increase mortality, such as oppositional defiant disorder or conduct disorder, criminality, accidents, and substance misuse. However, whether ADHD itself is associated with increased mortality remains unknown. We aimed to assess ADHD-related mortality in a large cohort of Danish individuals.

METHODS

By use of the Danish national registers, we followed up 1·92 million individuals, including 32,061 with ADHD, from their first birthday through to 2013. We estimated mortality rate ratios (MRRs), adjusted for calendar year, age, sex, family history of psychiatric disorders, maternal and paternal age, and parental educational and employment status, by Poisson regression, to compare individuals with and without ADHD.

FINDINGS

During follow-up (24·9 million person-years), 5580 cohort members died. The mortality rate per 10,000 person-years was 5·85 among individuals with ADHD compared with 2·21 in those without (corresponding to a fully adjusted MRR of 2·07, 95% CI 1·70-2·50; p<0·0001). Accidents were the most common cause of death. Compared with individuals without ADHD, the fully adjusted MRR for individuals diagnosed with ADHD at ages younger than 6 years was 1·86 (95% CI 0·93-3·27), and it was 1·58 (1·21-2·03) for those aged 6-17 years, and 4·25 (3·05-5·78) for those aged 18 years or older. After exclusion of individuals with oppositional defiant disorder, conduct disorder, and substance use disorder, ADHD remained associated with increased mortality (fully adjusted MRR 1·50, 1·11-1·98), and was higher in girls and women (2·85, 1·56-4·71) than in boys and men (1·27, 0·89-1·76).

INTERPRETATION

ADHD was associated with significantly increased mortality rates. People diagnosed with ADHD in adulthood had a higher MRR than did those diagnosed in childhood and adolescence. Comorbid oppositional defiant disorder, conduct disorder, and substance use disorder increased the MRR even further. However, when adjusted for these comorbidities, ADHD remained associated with excess mortality, with higher MRRs in girls and women with ADHD than in boys and men with ADHD. The excess mortality in ADHD was mainly driven by deaths from unnatural causes, especially accidents.

FUNDING

This study was supported by a grant from the Lundbeck Foundation.

Consequences of ADHD medication use for children's outcomes

This paper estimates effects of early ADHD medication use on key human capital outcomes for children diagnosed with ADHD while using rarely available register based data on diagnoses and prescription drug purchases. Our main identification strategy exploits plausible exogenous assignment of children to hospitals with specialist physicians, while our analysis of health outcomes also allows for an individual level panel data strategy. We find that the behavior of specialist physicians varies considerably across hospitals and that the prescribing behavior does affect the probability that a given child is treated. Results show that children diagnosed with ADHD in pharmacological treatment have fewer hospital contacts if treated and that treatment to some extent protects against criminal behavior.

Cardiovascular safety of stimulants in children with attention-deficit/hyperactivity disorder: a nationwide prospective cohort study

OBJECTIVE

The purpose of this study was to determine whether stimulant users are at higher risk of a later cardiovascular event than are non-users, examining this association in both a national cohort and a population-based sample of children and adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD). We also aim to examine a possible dose-response relationship in such an association.

METHODS

We conducted a longitudinal, prospective cohort study of all children born in Denmark between 1990 and 1999. Within this cohort, children with ADHD were identified. Data from national health registers on psychiatric and somatic diagnoses, stimulant prescriptions, cardiovascular risk factors, pre- and perinatal and sociodemographic covariates in all children and their parents were merged, using the unique personal identification number. Hazard ratios (HR) for cardiovascular events were estimated using Cox regression, adjusted for other known risk factors.

RESULTS

In the total population (n=714,258 contributing a total of 6,767,982 person-years) use of stimulants increased the risk of a cardiovascular event; adjusted HR=1.83 (1.10-3.04). In children with ADHD (n=8300) stimulant treatment also increased the risk of a cardiovascular event (adjusted HR=2.20 [2.15-2.24]), with a complex time-dependent dose-response relationship.

CONCLUSIONS

This is the first nationwide cohort study of the cardiovascular safety of stimulants in children and adolescents, and it represents, to our knowledge, the longest prospective follow-up study. Cardiovascular events were rare but twice as likely in stimulant users as in non-users, both in the total national population and in children with ADHD. We found a complex, time- and dose-dependent interrelationship between cardiovascular adverse events and stimulant treatment in children and adolescents. Our results suggest a safety signal with an increased risk of cardiovascular disease associated with stimulant treatment in children and adolescents, even after adjusting for a number of potential confounders.