Posttraumatic stress disorder in adult attention-deficit/hyperactivity disorder: clinical features and familial transmission

Objective: Attention-deficit/hyperactivity disorder (ADHD) is characterized by clinically significant functional impairment due to symptoms of inattention and/or hyperactivity and impulsivity. Previous research suggests a link, in child samples, between ADHD and posttraumatic stress disorder (PTSD), which is characterized by (1) chronically reexperiencing a traumatic event, (2) hyperarousal, and (3) avoiding stimuli associated with the trauma while exhibiting numbed responsiveness. This study sought to address the link between ADHD and PTSD in adults by providing a comprehensive comparison of ADHD patients with and without PTSD across multiple variables including demographics, patterns of psychiatric comorbidities, functional impairments, quality of life, social adjustment, and familial transmission.

Method: Participants in our controlled family study conducted between 1998 and 2003 were 190 adults with DSM-IV ADHD who were attending an outpatient mental health clinic in Boston, Massachusetts; 16 adults with DSM-IV ADHD who were recruited by advertisement from the greater Boston area; and 123 adult controls without ADHD who were recruited by advertisement from the greater Boston area. All available first-degree relatives also participated. Subjects completed a large battery of self-report measures (the Quality of Life Enjoyment and Satisfaction Questionnaire, items from the Current Behavior Scale, the Social Adjustment Scale Self-Report, and the Four Factor Index of Social Status) designed to assess various psychiatric and functional parameters. Diagnoses were made using data obtained from structured psychiatric interviews (Structured Clinical Interview for DSM-IV Axis I Disorders, Clinician Version, and the Schedule for Affective Disorders and Schizophrenia for School-Aged Children-Epidemiologic Version).

Results: The lifetime prevalence of PTSD was significantly higher among adults with ADHD compared with controls (10.0% vs 1.6%; P = .004). Participants with ADHD and those with ADHD + PTSD did not differ in core symptoms of ADHD nor in age at onset, but those with ADHD + PTSD had higher rates of psychiatric comorbidity than those with ADHD only (including higher lifetime rates of major depressive disorder, oppositional defiant disorder, social phobia, agoraphobia, and generalized anxiety disorder) and worse quality of life ratings for all domains. Familial risk analysis revealed that relatives of ADHD probands without PTSD had elevated rates of both ADHD (51%) and PTSD (12%) that significantly differed from rates among relatives of controls (7% [P ≤ .001] and 0% [P ≤ .05], respectively). A similar pattern of elevated risk for ADHD and PTSD (80% and 40%) was observed in relatives of probands with ADHD + PTSD (P ≤ .001 for both conditions).

Conclusions: The comorbidity of PTSD and ADHD in adults leads to greater clinical severity in terms of psychiatric comorbidity and psychosocial functioning. The familial coaggregation of the 2 disorders suggests that these disorders share familial risk factors and that their co-occurrence is not due to diagnostic errors.