Comorbid Psychiatric Disorders in Adults with ADHD

Abstract

Adults with ADHD have been found in prior studies to have a greater risk for various psychiatric disorders. Chief among these are oppositional defiant disorder (ODD) and conduct disorder (CD). Approximately 24–35% of clinic–referred adults diagnosed with ADHD have ODD and 17–25% have CD, either currently or over the course of their earlier development (Barkley, Murphy, & Kwasnik, 1996; Biederman, et al., 1993; Murphy & Barkley, 1996; Murphy, Barkley, & Bush, 2002; Spencer, 2004). These figures for clinic–referred adults are below those reported in studies of ADHD children, particularly studies of hyperactive children followed to adulthood, where levels of ODD and CD may be double or triple these rates reported for adults diagnosed with ADHD (see Barkley, 2006, for a review; Barkley, Fischer, Edelbrock, & Smallish, 1990; Fischer, Barkley, Smallish, & Fletcher, 2002; Weiss & Hechtman, 1993). Among parents of children having ADHD who also meet criteria for ADHD, disruptive behavior disorders are also significantly more common (McGough et al., 2005; Minde, et al., 2003). For instance, one study found that 53% have had ODD and 33% have had CD sometime in their lives (Biederman et al., 1993), figures closer to those seen in follow–up studies of hyperactive or ADHD children. Antisocial Personality Disorder is often an associated adult outcome in a large minority of those children or adolescents who have both ADHD and CD; thus it is not surprising to find that 7–44% of clinic–referred adults diagnosed with ADHD also qualify for a diagnosis of this personality disorder (Biederman et al., 1993; Shekim, Asarnow, Hess, Zaucha, & Wheeler, 1990; Torgersen, Gjervab, & Rasmussen, 2006). Even among those who do not qualify for this diagnosis, many receive higher than normal ratings on those personality traits associated with this personality disorder (Tzelepis, Schubiner, & Warbase, 1995). Substance dependence and abuse are known to occur to a more frequent degree among hyperactive or ADHD children who develop CD by adolescence or Antisocial Personality Disorder by adulthood (Barkley, 2006; Tercyak, Peshkin, Walker, & Stein, 2002). Arecent study of a large general population sample likewise found an association between ADHD and antisocial disorder (Kessler, et al., 2006). Adults clinically diagnosed with ADHD seem to be no exception to this rule linking ADHD, antisocial activities, and drug use disorders. Studies have found lifetime rates of alcohol dependence or abuse disorders ranging between 21% and 53% of adults diagnosed with ADHD, whereas 8–32% may manifest some other form of substance dependence or abuse disorder (Barkley,