Twin Study of the Relationship Between Adolescent Attention-Deficit/Hyperactivity Disorder and Adult Alcohol Dependence

Abstract

ABSTRACT. Objective: Adolescent problem behaviors such as conduct disorder and attention-defi cit/hyperactivity disorder (ADHD) are often associated with alcohol problems in adulthood, particularly alcohol dependence. This association is partly a result of shared genetic liability. However, it is unclear whether ADHD, or an ADHD subtype, shares genetic infl uences with alcohol dependence beyond those also shared by conduct disorder. Method: We evaluated phenotypic associations between adolescent conduct disorder and ADHD phenotypes with adult alcohol dependence in a population-based sample of adult male twins (N = 1,774). We then assessed genetic and environmental relationships among phenotypes using structural equation modeling. Results: Individually, conduct disorder and each ADHD factor were associated with adult alcohol dependence. Results from twin modeling indicate that a genetic factor common to conduct disorder and ADHD also loads strongly onto alcohol dependence. Even after controlling for genetic factors shared with conduct disorder and other ADHD factors, the hyperactivity component of ADHD shared signifi cant residual genetic infl uences with alcohol dependence. Conclusions: Most of the genetically mediated association between adolescent ADHD and adult alcohol dependence is shared with conduct disorder, refl ecting a generalized risk to externalizing behaviors. The signifi cant residual genetic covariance between the ADHD factor hyperactivity/impulsivity and alcohol dependence implies that impulsive behaviors less destructive/harmful than those manifested by conduct disorder can be indicative of genetic risk for adult alcohol dependence. However, the ADHD factors inattention and forgetfulness are not uniquely predictive of genetic/environmental risk for alcohol dependence. (J. Stud. Alcohol Drugs, 73, 185-194, 2012)

Attention-Deficit/Hyperactivity Disorder and Substance Abuse

“…36 Another theory proposes a common genetic factor underlying both ADHD and risk of SUDs, although more studies are needed to further evaluate this association. 37,38 Children and adolescents with ADHD have higher rates of grade retention and school dropout than those without ADHD. 39,40 These academic failures may increase an individual' s likelihood to use drugs as a means to escape anxiety about school.…”

Attention-Deficit/Hyperactivity Disorder and Risk for Substance Use Disorders in Relatives

“…The fact that some previous studies have used broad definitions of SUD (4-7), while others have explored the relationship between ADHD and specific SUD subtypes (such as psychoactive drug abuse, alcohol use disorder and nicotine dependence) (8)(9)(10)(11)(12)(13) makes comparisons across studies difficult. Furthermore, since SUD, and particularly alcohol use disorder, is rare in childhood but increasing in prevalence with age through adolescence and into adulthood, short follow-up time is a serious limitation of many previous studies looking at the association between ADHD and SUD (4, 9).…”

“…Some genetically informed studies suggest shared genetic risk factors for ADHD and SUD (11,15,16), while other family-based studies indicate independent transmission of SUD and ADHD, or alternatively, the presence of an etiologically distinct ADHD plus SUD syndrome (7,9,12). Clearly, additional research is needed to resolve the conflicting results of previous research.…”

Environmental and Genetic Influences in Attention Deficit Hyperactivity Disorder (ADHD) and its Comorbidities

“…Prior research regarding the role of the ADHD subtypes in comorbidities with SUD is conflicting. Some authors find an association mainly between the HI subtype with SUD (76,79,80); others identified more SUD in the combined (CO) subtype (81). The IN subtype has mainly been associated with increased nicotine dependence (82)(83)(84)(85).…”

“…Research regarding the overlap between ADHD and comorbid conditions initially also focused on children, identifying common genetic factors for externalizing disorders (79,(117)(118)(119), with autism spectrum disorder (ASD) (120), cognitive performance such as reading problems (121), as well as with psychiatric disorders such as mood disorder (122). More recently, common genetic factors have been identified in adults for a wide range of psychiatric disorders, indicating involvement of a set of pleiotropic genes (123).…”