A population-based multigenerational family co-aggregation study of severe infections and obsessive-compulsive disorder.

BACKGROUND: Postinfectious autoimmune processes have been proposed as potential causal factors for obsessive-compulsive disorder (OCD). This large population-based study aimed to clarify the co-aggregation pattern between severe infections and OCD across clusters of relatives with varying degrees of relatedness. METHODS: We identified 4,916,898 individuals born in Sweden between 1960 and 2008 and followed them until 2020. Each individual was linked to their first- and second-degree relatives, including monozygotic (MZ) and dizygotic (DZ) twins, mothers, fathers, full siblings, maternal and paternal half siblings, aunts, uncles, and cousins. OCD and infection diagnoses from inpatient and specialized outpatient units were retrieved from the Swedish National Patient Register. We compared the risk of OCD in relatives of probands with severe infections to those of probands without severe infections. Cox proportional hazard regression models, incorporating time-varying exposures, were used to estimate hazard ratios (HRs). Dose-response associations were examined using logistic regression models. RESULTS: Relatives of probands with severe infections exhibited a higher risk of OCD, increasing with genetic relatedness, with HRs (95% CI) ranging from 1.46 (1.07-1.98) in MZ twins to 1.10 (1.09-1.11) in cousins. The results remained robust after adjusting for severe infections among relatives, OCD in probands, and comorbid autoimmune disorders in both probands and relatives. A dose-response association was observed between the number of infections in the probands and their odds of OCD, as well as in their relatives. CONCLUSIONS: The results strongly suggest that the association between severe infections and OCD may be largely driven by shared genetic factors.

Cumulative ADHD medication use and risk of type 2 diabetes in adults: a Swedish Register study.

BACKGROUND: Little is known about the impact of cumulative attention-deficit/hyperactivity disorder (ADHD) medication use on the risk of type 2 diabetes (T2D). OBJECTIVE: The objective is to examine the association between cumulative use of ADHD medication and risk of incident T2D. METHODS: A nested case-control study was conducted in a national cohort of individuals aged 18-70 years with incident ADHD (n=138 778) between 2007 and 2020 through Swedish registers. Individuals with incident T2D after ADHD were selected as cases (n=2355) and matched with up to five controls (n=11 681) on age at baseline, sex and birth year. Conditional logistic regression models examined the association between cumulative duration of ADHD medication use and T2D. FINDINGS: Compared with no use, a decreased risk of T2D was observed for those on cumulative use of ADHD medications up to 3 years (ORs: 03 years, 0.97 (95% CI, 0.84 to 1.12)). When investigating medication types separately, methylphenidate showed results similar to main analyses, lisdexamfetamine showed no association with T2D, whereas long-term (>3 years) use of atomoxetine was associated with an increased risk of T2D (OR: 1.44 (95% CI, 1.01 to 2.04)). CONCLUSION: Cumulative use of ADHD medication does not increase the risk for T2D, with the exception of long-term use of atomoxetine. CLINICAL IMPLICATIONS: Findings suggest that clinicians should be aware of the potential risk of T2D associated with the cumulative use of atomoxetine among patients with ADHD; however, further replication is strongly needed.

Incident Benzodiazepine and Z-Drug Use and Subsequent Risk of Serious Infections.

BACKGROUND AND OBJECTIVES: Animal studies have suggested a link between benzodiazepine and related Z-drug (BZDR) use and immune dysfunction. Corresponding evidence in humans is limited and focuses mainly on pneumonia. This study aimed to assess the association of incident BZDR use with subsequent development of serious infections. METHODS: This Swedish register-based study included a population-based demographically matched cohort, a co-twin control cohort, and an active comparator cohort. Out of 7,362,979 individuals aged below 65 years who were BZDR naïve by 2007, 713,896 BZDR recipients with incident dispensation of any BZDRs between 2007 and 2019 were 1:1 matched to 713,896 nonrecipients from the general population; 9197 BZDR recipients were compared with their 9298 unexposed co-twins/co-multiples; and 434,900 BZDR recipients were compared with 428,074 incident selective serotonin reuptake inhibitor (SSRI) recipients. The outcomes were identified by the first inpatient or specialist outpatient diagnosis of serious infections in the National Patient Register, or death from any infections recorded as the underlying cause in the Cause of Death Register. Cox proportional hazards regression models were fitted and controlled for multiple confounders, including familial confounding and confounding by indication. To study a possible dose-response association, the cumulative dosage of BZDRs dispensed during the follow-up was estimated for each BZDR recipient and modeled as a time-varying exposure with dose categories in tertiles [≤ 20 defined daily doses (DDDs), > 20 DDDs ≤ 65, and > 65 DDDs). The risk of infections was assessed in BZDR recipients within each category of the cumulative BZDR dosage compared to their demographically matched nonrecipients. RESULTS: In the demographically matched cohort (average age at incident BZDR use 42.8 years, 56.9% female), the crude incidence rate of any serious infections in BZDR recipients and matched nonrecipients during 1-year follow-up was 4.18 [95% confidence intervals (CI) 4.13-4.23] and 1.86 (95% CI 1.83-1.89) per 100 person-years, respectively. After controlling for demographic, socioeconomic, clinical, and pharmacological confounders, BZDR use was associated with 83% relative increase in risk of any infections [hazard ratio (HR) 1.83, 95% CI 1.79-1.89]. The risk remained increased, although attenuated, in the co-twin cohort (HR 1.55, 95% CI 1.23-1.97) and active comparator cohort (HR 1.33, 95% CI 1.30-1.35). The observed risks were similar across different types of initial BZDRs and across individual BZDRs, and the risks increased with age at BZDR initiation. We also observed a dose-response association between cumulative BZDR dosage and risk of serious infections. CONCLUSIONS: BZDR initiation was associated with increased risks of serious infections, even when considering unmeasured familial confounding and confounding by indication. The exact pathways through which BZDRs may affect immune function, however, remain unclear. Further studies are needed to explore the neurobiological mechanisms underlying the association between BZDR use and serious infections, as it can lead to safer therapeutic strategies for patients requiring BZDR.

The role of co-occurring conditions and genetics in the associations of eating disorders with attention-deficit/hyperactivity disorder and autism spectrum disorder.

Eating disorders (EDs) commonly co-occur with other psychiatric and neurodevelopmental disorders including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD); however, the pattern of family history and genetic overlap among them requires clarification. This study investigated the diagnostic, familial, and genetic associations of EDs with ADHD and ASD. The nationwide population-based cohort study included all individuals born in Denmark, 1981-2008, linked to their siblings and cousins. Cox regression was used to estimate associations between EDs and ADHD or ASD, and mediation analysis was used to assess the effects of intermediate mood or anxiety disorders. Polygenic scores (PGSs) were used to investigate the genetic association between anorexia nervosa (AN) and ADHD or ASD. Significantly increased risk for any ED was observed following an ADHD [hazard ratio = 1.97, 95% confidence interval = 1.75-2.22] or ASD diagnosis [2.82, 2.48-3.19]. Mediation analysis suggested that intermediate mood or anxiety disorders could account for 44-100% of the association between ADHD or ASD and ED. Individuals with a full sibling or maternal halfsibling with ASD had increased risk of AN [1.54, 1.33-1.78; 1.45, 1.08-1.94] compared to those with siblings without ASD. A positive association was found between ASD-PGS and AN risk [1.06, 1.02-1.09]. In this study, positive phenotypic associations between EDs and ADHD or ASD, mediation by mood or anxiety disorder, and a genetic association between ASD-PGS and AN were observed. These findings could guide future research in the development of new treatments that can mitigate the development of EDs among individuals with ADHD or ASD.

Shared familial risk for type 2 diabetes mellitus and psychiatric disorders: a nationwide multigenerational genetics study.

BACKGROUND: Psychiatric disorders and type 2 diabetes mellitus (T2DM) are heritable, polygenic, and often comorbid conditions, yet knowledge about their potential shared familial risk is lacking. We used family designs and T2DM polygenic risk score (T2DM-PRS) to investigate the genetic associations between psychiatric disorders and T2DM. METHODS: We linked 659 906 individuals born in Denmark 1990-2000 to their parents, grandparents, and aunts/uncles using population-based registers. We compared rates of T2DM in relatives of children with and without a diagnosis of any or one of 11 specific psychiatric disorders, including neuropsychiatric and neurodevelopmental disorders, using Cox regression. In a genotyped sample (iPSYCH2015) of individuals born 1981-2008 (n = 134 403), we used logistic regression to estimate associations between a T2DM-PRS and these psychiatric disorders. RESULTS: Among 5 235 300 relative pairs, relatives of individuals with a psychiatric disorder had an increased risk for T2DM with stronger associations for closer relatives (parents:hazard ratio = 1.38, 95% confidence interval 1.35-1.42; grandparents: 1.14, 1.13-1.15; and aunts/uncles: 1.19, 1.16-1.22). In the genetic sample, one standard deviation increase in T2DM-PRS was associated with an increased risk for any psychiatric disorder (odds ratio = 1.11, 1.08-1.14). Both familial T2DM and T2DM-PRS were significantly associated with seven of 11 psychiatric disorders, most strongly with attention-deficit/hyperactivity disorder and conduct disorder, and inversely with anorexia nervosa. CONCLUSIONS: Our findings of familial co-aggregation and higher T2DM polygenic liability associated with psychiatric disorders point toward shared familial risk. This suggests that part of the comorbidity is explained by shared familial risks. The underlying mechanisms still remain largely unknown and the contributions of genetics and environment need further investigation.

Intentional Self-Harm and Death by Suicide in Body Dysmorphic Disorder: A Nationwide Cohort Study.

BACKGROUND: Body dysmorphic disorder (BDD) is thought to be associated with considerable suicide risk. This nationwide cohort study quantified the risks of intentional self-harm-including nonsuicidal self-injuries and suicide attempts-and death by suicide in BDD. METHODS: Individuals with a validated ICD-10 diagnosis of BDD in the Swedish National Patient Register, registered between January 1, 1997, and December 31, 2020, were matched with 10 unexposed individuals (i.e., without BDD) from the general population on birth year, sex, and county of residence. Conditional Poisson regression models estimated incidence rate ratios and 95% CIs for intentional self-harm. Stratified Cox proportional hazards models estimated hazard ratios and 95% CIs for death by suicide. Models adjusted for sociodemographic variables and lifetime psychiatric comorbidities. RESULTS: Among 2833 individuals with BDD and 28,330 unexposed matched individuals, 466 (16.45%) and 1071 (3.78%), respectively, had at least 1 record of intentional self-harm during the study period (incidence rate ratio = 3.37; 95% CI, 3.02-3.76). In the BDD group, about two-thirds (n = 314; 67%) had their first recorded self-harm event before their first BDD diagnosis. A total of 17 (0.60%) individuals with BDD and 27 (0.10%) unexposed individuals died by suicide (hazard ratio = 3.47; 95% CI, 1.76-6.85). All results remained robust to additional adjustment for lifetime psychiatric comorbidities. A higher proportion of individuals with BDD who died by suicide had at least 1 previous record of intentional self-harm compared with unexposed individuals (52.94% vs. 22.22%; p = .036). CONCLUSIONS: BDD was associated with a 3-fold increased risk of intentional self-harm and death by suicide.

Associations between attention-deficit hyperactivity disorder genetic liability and ICD-10 medical conditions in adults: utilizing electronic health records in a Phenome-Wide Association Study.

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is often comorbid with other medical conditions in adult patients. However, ADHD is extremely underdiagnosed in adults and little is known about the medical comorbidities in undiagnosed adult individuals with high ADHD liability. In this study we investigated associations between ADHD genetic liability and electronic health record (EHR)-based ICD-10 diagnoses across all diagnostic categories, in individuals without ADHD diagnosis history. METHODS: We used data from the Estonian Biobank cohort (N = 111 261) and generated polygenic risk scores (PRS) for ADHD (PRSADHD) based on the ADHD genome-wide association study. We performed a phenome-wide association study (PheWAS) to test for associations between standardized PRSADHD and 1515 EHR-based ICD-10 diagnoses in the full and sex-stratified sample. We compared the observed significant ICD-10 associations to associations with (1) ADHD diagnosis and (2) questionnaire-based high ADHD risk analyses. RESULTS: After Bonferroni correction (p = 3.3 × 10-5) we identified 80 medical conditions associated with PRSADHD. The strongest evidence was seen with chronic obstructive pulmonary disease (OR 1.15, CI 1.11-1.18), obesity (OR 1.13, CI 1.11-1.15), and type 2 diabetes (OR 1.11, CI 1.09-1.14). Sex-stratified analysis generally showed similar associations in males and females. Out of all identified associations, 40% and 78% were also observed using ADHD diagnosis or questionnaire-based ADHD, respectively, as the predictor. CONCLUSIONS: Overall our findings indicate that ADHD genetic liability is associated with an increased risk of a substantial number of medical conditions in undiagnosed individuals. These results highlight the need for timely detection and improved management of ADHD symptoms in adults.

ADHD Pharmacotherapy and Mortality in Individuals With ADHD.

Importance: Attention-deficit/hyperactivity disorder (ADHD) is associated with increased risks of adverse health outcomes including premature death, but it is unclear whether ADHD pharmacotherapy influences the mortality risk. Objective: To investigate whether initiation of ADHD pharmacotherapy was associated with reduced mortality risk in individuals with ADHD. Design, Setting, and Participants: In an observational nationwide cohort study in Sweden applying the target trial emulation framework, we identified individuals aged 6 through 64 years with an incident diagnosis of ADHD from 2007 through 2018 and no ADHD medication dispensation prior to diagnosis. Follow-up started from ADHD diagnosis until death, emigration, 2 years after ADHD diagnosis, or December 31, 2020, whichever came first. Exposures: ADHD medication initiation was defined as dispensing of medication within 3 months of diagnosis. Main Outcomes and Measures: We assessed all-cause mortality within 2 years of ADHD diagnosis, as well as natural-cause (eg, physical conditions) and unnatural-cause mortality (eg, unintentional injuries, suicide, and accidental poisonings). Results: Of 148 578 individuals with ADHD (61 356 females [41.3%]), 84 204 (56.7%) initiated ADHD medication. The median age at diagnosis was 17.4 years (IQR, 11.6-29.1 years). The 2-year mortality risk was lower in the initiation treatment strategy group (39.1 per 10 000 individuals) than in the noninitiation treatment strategy group (48.1 per 10 000 individuals), with a risk difference of -8.9 per 10 000 individuals (95% CI, -17.3 to -0.6). ADHD medication initiation was associated with significantly lower rate of all-cause mortality (hazard ratio [HR], 0.79; 95% CI, 0.70 to 0.88) and unnatural-cause mortality (2-year mortality risk, 25.9 per 10 000 individuals vs 33.3 per 10 000 individuals; risk difference, -7.4 per 10 000 individuals; 95% CI, -14.2 to -0.5; HR, 0.75; 95% CI, 0.66 to 0.86), but not natural-cause mortality (2-year mortality risk, 13.1 per 10 000 individuals vs 14.7 per 10 000 individuals; risk difference, -1.6 per 10 000 individuals; 95% CI, -6.4 to 3.2; HR, 0.86; 95% CI, 0.71 to 1.05). Conclusions and Relevance: Among individuals diagnosed with ADHD, medication initiation was associated with significantly lower all-cause mortality, particularly for death due to unnatural causes.

Attention-Deficit Hyperactivity Disorder (ADHD) Medication Use Trajectories Among Women in the Perinatal Period.

BACKGROUND: An increasing number of women of reproductive age are treated with attention-deficit hyperactivity disorder (ADHD) medication; however, patterns of ADHD medication use for women in the perinatal period have not been well described. OBJECTIVE: This study aimed to describe ADHD medication use patterns from 1 year before pregnancy to 1 year after delivery, and to describe sociodemographic characteristics and clinical features by medication trajectories. METHODS: The population-based cohort study included pregnancies in Denmark between 1997 and 2020, from the Medical Birth Register, by women who filled at least one prescription for ADHD medication from 12 months before pregnancy until 12 months after delivery. We applied group-based trajectory modeling to classify women into subgroups based on the identification of heterogeneous ADHD medication treatment patterns, and described the characteristics associated with these groups. RESULTS: Overall, we included 4717 pregnancies leading to liveborn singletons by 4052 mothers with a mean (standard deviation) age of 27.5 (5.6) years. We identified four treatment trajectories across pregnancy and the postpartum period: continuers (23.3%), discontinuers (41.8%), interrupters who ceased filling prescriptions during pregnancy but resumed postpartum (17.2%), and postpartum initiators (17.7%). Continuers were older at the time of conception, gave birth in more recent years, were more likely to smoke during pregnancy, and used other psychotropic medications during pregnancy. A large proportion of continuers used methylphenidate (89.1%) compared with the other groups (75.9-84.1%) and had switched ADHD medication type during the whole period (16.4% vs. 7.4-14.8%). CONCLUSION: We found that approximately 60% of women discontinued or interrupted their ADHD medication around pregnancy, and those who continued differed in sociodemographic and clinical factors that may reflect more severe ADHD.

Attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD; also known as hyperkinetic disorder) is a common neurodevelopmental condition that affects children and adults worldwide. ADHD has a predominantly genetic aetiology that involves common and rare genetic variants. Some environmental correlates of the disorder have been discovered but causation has been difficult to establish. The heterogeneity of the condition is evident in the diverse presentation of symptoms and levels of impairment, the numerous co-occurring mental and physical conditions, the various domains of neurocognitive impairment, and extensive minor structural and functional brain differences. The diagnosis of ADHD is reliable and valid when evaluated with standard diagnostic criteria. Curative treatments for ADHD do not exist but evidence-based treatments substantially reduce symptoms and/or functional impairment. Medications are effective for core symptoms and are usually well tolerated. Some non-pharmacological treatments are valuable, especially for improving adaptive functioning. Clinical and neurobiological research is ongoing and could lead to the creation of personalized diagnostic and therapeutic approaches for this disorder.

All cause and cause specific mortality in obsessive-compulsive disorder: nationwide matched cohort and sibling cohort study.

OBJECTIVE: To estimate the risk of all cause and cause specific mortality in people with obsessive-compulsive disorder (OCD) compared with matched unaffected people from the general population and with their unaffected siblings. DESIGN: Population based matched cohort and sibling cohort study. SETTING: Register linkage in Sweden. PARTICIPANTS: Population based cohort including 61 378 people with OCD and 613 780 unaffected people matched (1:10) on sex, birth year, and county of residence; sibling cohort consisting of 34 085 people with OCD and 47 874 unaffected full siblings. Cohorts were followed up for a median time of 8.1 years during the period from 1 January 1973 to 31 December 2020. MAIN OUTCOME MEASURES: All cause and cause specific mortality. RESULTS: 4787 people with OCD and 30 619 unaffected people died during the study period (crude mortality rate 8.1 and 5.1 per 1000 person years, respectively). In stratified Cox proportional hazards models adjusted for birth year, sex, county, migrant status (born in Sweden versus abroad), and sociodemographic variables (latest recorded education, civil status, and family income), people with OCD had an increased risk of all cause mortality (hazard ratio 1.82, 95% confidence interval 1.76 to 1.89) and mortality due to natural causes (1.31, 1.27 to 1.37) and unnatural causes (3.30, 3.05 to 3.57). Among the natural causes of death, those due to endocrine, nutritional, and metabolic diseases, mental and behavioural disorders, and diseases of the nervous, circulatory, respiratory, digestive, and genitourinary systems were higher in the OCD cohort. Conversely, the risk of death due to neoplasms was lower in the OCD cohort compared with the unaffected cohort. Among the unnatural causes, suicide showed the highest hazard ratio, followed by accidents. The results were robust to adjustment for psychiatric comorbidities and familial confounding. CONCLUSIONS: Non-communicable diseases and external causes of death, including suicides and accidents, were major contributors to the risk of mortality in people with OCD. Better surveillance, prevention, and early intervention strategies should be implemented to reduce the risk of fatal outcomes in people with OCD.

Attention-Deficit/Hyperactivity Disorder and Major Depressive Disorder: Evidence From Multiple Genetically Informed Designs.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) and major depressive disorder (MDD) are two highly prevalent disorders that frequently co-occur. Prior evidence from genetic and cohort studies supports an association between ADHD and MDD. However, the direction and mechanisms underlying their association remain unclear. As onset of ADHD occurs in early life, it has been hypothesized that ADHD may cause MDD. METHODS: We examined the association of ADHD with MDD using 3 different genetically informed methods to disentangle causality from confounding: 1) a nationwide longitudinal register-based full sibling comparison (N = 1,018,489) adjusting for shared familial confounding; 2) a prospective co-twin control study comprising 16,477 twins (5084 monozygotic and 11,393 dizygotic); and 3) a two-sample Mendelian randomization analysis using the largest available ADHD (N = 225,534) and MDD (N = 500,199) genome-wide association study summary statistics, adjusting for correlated and uncorrelated horizontal pleiotropy. RESULTS: Sibling and twin comparisons indicated that individuals with ADHD have an increased risk for subsequent development of MDD (hazard ratio = 4.12 [95% CI 3.62-4.69]) after adjusting for shared genetic and familial factors and that ADHD scores endorsed by parents are positively associated with subsequent MDD scores at ages 15 and 18 years (b = 0.07 [95% CI 0.05-0.08] and b = 0.09 [95% CI 0.08-0.11], respectively). Mendelian randomization analyses showed that genetic liability for ADHD is causally related to MDD (odds ratio = 1.15 [95% CI 1.08-1.23]). CONCLUSIONS: Our study provides consistent results across 3 different genetically informative approaches, strengthening the hypothesis that ADHD is causally related to MDD.

Antidepressant Use and Risk of Manic Episodes in Children and Adolescents With Unipolar Depression.

Importance: Antidepressants are increasingly prescribed to pediatric patients with unipolar depression, but little is known about the risk of treatment-emergent mania. Previous research suggests pediatric patients may be particularly vulnerable to this adverse outcome. Objective: To estimate whether pediatric patients treated with antidepressants have an increased incidence of mania/hypomania compared with patients not treated with antidepressants and to identify patient characteristics associated with the risk of mania/hypomania. Design, Setting, and Participants: In a cohort study applying the target trial emulation framework, nationwide inpatient and outpatient care in Sweden from July 1, 2006, to December 31, 2019, was evaluated. Follow-up was conducted for 12 and 52 weeks after treatment initiation, with administrative follow-up ending December 31, 2020. Data were analyzed between May 1, 2022, and June 28, 2023. Individuals aged 4 to 17 years with a diagnosis of depression, but without a prior diagnosis of mania/hypomania, bipolar disorder, or psychosis or treatment with mood stabilizer (lithium, valproate, or carbamazepine), prescriptions were included. Exposures: The treatment group included patients who initiated any antidepressant medication within 90 days of diagnosis. The control group included patients who did not initiate antidepressants within 90 days. Main Outcomes and Measures: Diagnosis of mania/hypomania or initiation of mood stabilizer therapy. Incidences were estimated with Kaplan-Meier estimator, and inverse probability of treatment weighting was used to adjust for group differences at baseline. Results: The cohort included 43 677 patients (28 885 [66%] girls); 24 573 in the treatment group and 19 104 in the control group. The median age was 15 (IQR, 14-16) years. The outcome occurred in 96 individuals by 12 weeks and in 291 by 52 weeks. The cumulative incidence of mania was 0.26% (95% CI, 0.19%-0.33%) in the treatment group and 0.20% (95% CI, 0.13%-0.27%) in the control group at 12 weeks, with a risk difference of 0.06% (95% CI, -0.04% to 0.16%). At 52 weeks, the cumulative incidence was 0.79% (95% CI, 0.68%-0.91%) in the treatment group and 0.52% (95% CI, 0.40%-0.63%) in the control group (risk difference, 0.28%; 95% CI, 0.12%-0.44%). Hospitalizations, parental bipolar disorder, and use of antipsychotics and antiepileptics were the most important predictors of mania/hypomania by 12 weeks. Conclusion: This cohort study found no evidence of treatment-emergent mania/hypomania by 12 weeks in children and adolescents. This corresponds to the time frame for antidepressants to exert their psychotropic effect. A small risk difference was found only with longer follow-up. Certain patient characteristics were associated with mania/hypomania, which warrants clinical attention.

Attention-Deficit/Hyperactivity Disorder Medications and Long-Term Risk of Cardiovascular Diseases.

Importance: Use of attention-deficit/hyperactivity disorder (ADHD) medications has increased substantially over the past decades. However, the potential risk of cardiovascular disease (CVD) associated with long-term ADHD medication use remains unclear. Objective: To assess the association between long-term use of ADHD medication and the risk of CVD. Design, Setting, and Participants: This case-control study included individuals in Sweden aged 6 to 64 years who received an incident diagnosis of ADHD or ADHD medication dispensation between January 1, 2007, and December 31, 2020. Data on ADHD and CVD diagnoses and ADHD medication dispensation were obtained from the Swedish National Inpatient Register and the Swedish Prescribed Drug Register, respectively. Cases included individuals with ADHD and an incident CVD diagnosis (ischemic heart diseases, cerebrovascular diseases, hypertension, heart failure, arrhythmias, thromboembolic disease, arterial disease, and other forms of heart disease). Incidence density sampling was used to match cases with up to 5 controls without CVD based on age, sex, and calendar time. Cases and controls had the same duration of follow-up. Exposure: Cumulative duration of ADHD medication use up to 14 years. Main Outcomes and Measures: The primary outcome was incident CVD. The association between CVD and cumulative duration of ADHD medication use was measured using adjusted odds ratios (AORs) with 95% CIs. Results: Of 278 027 individuals with ADHD aged 6 to 64 years, 10 388 with CVD were identified (median [IQR] age, 34.6 [20.0-45.7] years; 6154 males [59.2%]) and matched with 51 672 control participants without CVD (median [IQR] age, 34.6 [19.8-45.6] years; 30 601 males [59.2%]). Median (IQR) follow-up time in both groups was 4.1 (1.9-6.8) years. Longer cumulative duration of ADHD medication use was associated with an increased risk of CVD compared with nonuse (0 to ≤1 year: AOR, 0.99 [95% CI, 0.93-1.06]; 1 to ≤2 years: AOR, 1.09 [95% CI, 1.01-1.18]; 2 to ≤3 years: AOR, 1.15 [95% CI, 1.05-1.25]; 3 to ≤5 years: AOR, 1.27 [95% CI, 1.17-1.39]; and >5 years: AOR, 1.23 [95% CI, 1.12-1.36]). Longer cumulative ADHD medication use was associated with an increased risk of hypertension (eg, 3 to ≤5 years: AOR, 1.72 [95% CI, 1.51-1.97] and >5 years: AOR, 1.80 [95% CI, 1.55-2.08]) and arterial disease (eg, 3 to ≤5 years: AOR, 1.65 [95% CI, 1.11-2.45] and >5 years: AOR, 1.49 [95% CI, 0.96-2.32]). Across the 14-year follow-up, each 1-year increase of ADHD medication use was associated with a 4% increased risk of CVD (AOR, 1.04 [95% CI, 1.03-1.05]), with a larger increase in risk in the first 3 years of cumulative use (AOR, 1.08 [95% CI, 1.04-1.11]) and stable risk over the remaining follow-up. Similar patterns were observed in children and youth (aged <25 years) and adults (aged ≥25 years). Conclusions and Relevance: This case-control study found that long-term exposure to ADHD medications was associated with an increased risk of CVDs, especially hypertension and arterial disease. These findings highlight the importance of carefully weighing potential benefits and risks when making treatment decisions about long-term ADHD medication use. Clinicians should regularly and consistently monitor cardiovascular signs and symptoms throughout the course of treatment.

ADHD medication discontinuation and persistence across the lifespan: a retrospective observational study using population-based databases.

BACKGROUND: Although often intended for long-term treatment, discontinuation of medication for ADHD is common. However, cross-national estimates of discontinuation are missing due to the absence of standardised measures. The aim of this study was to determine the rate of ADHD treatment discontinuation across the lifespan and to describe similarities and differences across countries to guide clinical practice. METHODS: We did a retrospective, observational study using population-based databases from eight countries and one Special Administrative Region (Australia, Denmark, Hong Kong, Iceland, the Netherlands, Norway, Sweden, the UK, and the USA). We used a common analytical protocol approach and extracted prescription data to identify new users of ADHD medication. Eligible individuals were aged 3 years or older who had initiated ADHD medication between 2010 and 2020. We estimated treatment discontinuation and persistence in the 5 years after treatment initiation, stratified by age at initiation (children [age 4-11 years], adolescents [age 12-17 years], young adults [age 18-24 years], and adults [age ≥25 years]) and sex. Ethnicity data were not available. FINDINGS: 1 229 972 individuals (735 503 [60%] males, 494 469 females [40%]; median age 8-21 years) were included in the study. Across countries, treatment discontinuation 1-5 years after initiation was lowest in children, and highest in young adults and adolescents. Within 1 year of initiation, 65% (95% CI 60-70) of children, 47% (43-51) of adolescents, 39% (36-42) of young adults, and 48% (44-52) of adults remained on treatment. The proportion of patients discontinuing was highest between age 18 and 19 years. Treatment persistence for up to 5 years was higher across countries when accounting for reinitiation of medication; at 5 years of follow-up, 50-60% of children and 30-40% of adolescents and adults were covered by treatment in most countries. Patterns were similar across sex. INTERPRETATION: Early medication discontinuation is prevalent in ADHD treatment, particularly among young adults. Although reinitiation of medication is common, treatment persistence in adolescents and young adults is lower than expected based on previous estimates of ADHD symptom persistence in these age groups. This study highlights the scope of medication treatment discontinuation and persistence in ADHD across the lifespan and provides new knowledge about long-term ADHD medication use. FUNDING: European Union Horizon 2020 Research and Innovation Programme.

Polygenic profiles define aspects of clinical heterogeneity in attention deficit hyperactivity disorder.

Attention deficit hyperactivity disorder (ADHD) is a complex disorder that manifests variability in long-term outcomes and clinical presentations. The genetic contributions to such heterogeneity are not well understood. Here we show several genetic links to clinical heterogeneity in ADHD in a case-only study of 14,084 diagnosed individuals. First, we identify one genome-wide significant locus by comparing cases with ADHD and autism spectrum disorder (ASD) to cases with ADHD but not ASD. Second, we show that cases with ASD and ADHD, substance use disorder and ADHD, or first diagnosed with ADHD in adulthood have unique polygenic score (PGS) profiles that distinguish them from complementary case subgroups and controls. Finally, a PGS for an ASD diagnosis in ADHD cases predicted cognitive performance in an independent developmental cohort. Our approach uncovered evidence of genetic heterogeneity in ADHD, helping us to understand its etiology and providing a model for studies of other disorders.

Attention-deficit/hyperactivity disorder is associated with increased risk of cardiovascular diseases: A systematic review and meta-analysis.

Attention-deficit/hyperactivity disorder (ADHD) often co-occurs with other psychiatric and physical diseases. However, available evidence on associations between ADHD and cardiovascular diseases (CVDs) is mixed. To systematically review, quantitatively synthesize, and appraise available evidence on the link between ADHD with CVDs, we searched relevant articles in PubMed, Embase, PsycINFO, and Web of Science from inception to May 1, 2022. Study quality was assessed by using the Newcastle-Ottawa Scale, and random-effects model meta-analyses were performed. A total of 18,391,169 (ADHD: n = 421,224) individuals from 11 studies were included in our systematic review and 8,196,648 (ADHD = 332,619) individuals from five studies were included in the main meta-analysis of adjusted estimates. Pooled estimates showed that ADHD was significantly associated with an increased risk of CVDs in analyses based on adjusted effect size (odds ratio (OR) = 1.96; 95% confidence interval (CI) = 1.19-2.23, Q = 140.74, P Q < 0.001, I 2 = 97.2%). When restricted among adults, the heterogeneity declined to null (OR = 1.73; 95% CI = 1.14-2.62, Q = 6.28, P Q = 0.10, I 2 = 6.28%), suggesting age might be the main source of heterogeneity. In subgroup analyses, we found increased risk of CVDs associated with ADHD across age groups, type of CVDs, and data sources. This systematic review and meta-analyses indicate that ADHD is associated with increased risk for CVDs, but further studies with various study designs are warranted to advance the understanding of the underlying mechanisms for the observed association between ADHD and CVDs. Additional research is also needed to resolve the role of ADHD medications which remains unclear due to the limited number of primary studies exploring this issue.

Multi-PGS enhances polygenic prediction by combining 937 polygenic scores.

The predictive performance of polygenic scores (PGS) is largely dependent on the number of samples available to train the PGS. Increasing the sample size for a specific phenotype is expensive and takes time, but this sample size can be effectively increased by using genetically correlated phenotypes. We propose a framework to generate multi-PGS from thousands of publicly available genome-wide association studies (GWAS) with no need to individually select the most relevant ones. In this study, the multi-PGS framework increases prediction accuracy over single PGS for all included psychiatric disorders and other available outcomes, with prediction R2 increases of up to 9-fold for attention-deficit/hyperactivity disorder compared to a single PGS. We also generate multi-PGS for phenotypes without an existing GWAS and for case-case predictions. We benchmark the multi-PGS framework against other methods and highlight its potential application to new emerging biobanks.