Comorbid psychiatric disorders in a clinical sample of adults with ADHD, and associations with education, work and social characteristics: a cross-sectional study.

Objectives: Adults with attention-deficit hyperactive disorder (ADHD) report high rates of comorbid disorders, educational and occupational failure, and family instability. The aim of this study was to examine the prevalence of comorbid psychiatric disorders in a clinical population of adults with ADHD and to examine associations between educational level, work participation, social characteristics and the rates of psychiatric comorbidity.

Methods: Out of 796 patients diagnosed with ADHD in a specialised outpatient clinic in Oslo, Norway, 548 (68%) agreed to participate in this cross-sectional study: 277 women and 271 men. ADHD was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. Comorbid disorders were diagnosed using the Mini-International Neuropsychiatric Interview.

Results: In this clinical sample, 53.5% had at least one current comorbid psychiatric disorder. The most prevalent disorders were major depression, substance use disorders and social phobia. Women had more eating disorders than men, whereas men had more alcohol and substance use disorders. Education above high school level (>12 years) and work participation were associated with lower rates of comorbid disorders (adjusted ORs 0.52 and 0.63, respectively). Gender, age, marital status, living with children or living in a city were not associated with comorbidity.

Conclusions: Adult ADHD is associated with high rates of comorbid psychiatric disorders, irrespective of gender and age. It appears that higher education and work participation are related to lower probability of comorbidity.