The impact of attention deficit hyperactivity disorder in obsessive-compulsive disorder subjects

Background Recent findings suggest an association between attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Thus, we evaluated the clinical associated features of ADHD in a large sample of adult OCD patients. Methods A cross-sectional study including 955 adult patients with OCD from the Brazilian Research Consortium of Obsessive-Compulsive Spectrum Disorders (C-TOC). Clinical characteristics in adult OCD patients with and without comorbid ADHD were compared using Fisher's exact test, t-tests or Mann-Whitney tests. Bivariate analyses were followed by logistic regression analysis to identify clinical characteristics independently associated with ADHD comorbidity. Results The lifetime prevalence of ADHD in adult OCD patients was 13.7%. The current results indicate that OCD + ADHD patients were more severe, had an earlier onset of the obsessive-compulsive symptoms, a higher history of rheumatic fever, with higher frequencies of sensory phenomena and comorbidity with Tourette syndrome. They also had an increased risk for academic impairment and suicide attempts. Conclusion Adult OCD patients with ADHD present some specific clinical features and may represent a special subgroup of adult OCD. Future studies should focus on the development of interventions more tailored to the phenotype of this subgroup of patients.