ADHD is a highly heritable neurodevelopmental syndrome with significant lifetime risk for psychiatric comorbidities. Several psychiatric conditions are significantly more common in patients with ADHD than in control subjects.

To evaluate the incidence of comorbid affective disorders, patients with adult ADHD who were first seen at the outpatient clinic of the Department of Psychiatry and Psychotherapy were evaluated for symptoms of major depression, brief recurrent depression, bipolar depression and anxiety disorders. Patients aged between 18 and 75 years were included into the study. All patients were evaluated according to DSM IV TR criteria. So far, from February 2007 until May 2010, 330 patients (192 males and 138 females) were included into the study.

The mean age of the patients at diagnosis was 33, 7 years for males (range: 18-75) and 35, 9 years for females (range: 18–64). Affective disorders were most frequently diagnosed as comorbid conditions in our patients and occurred in 26% of the patients in our sample. 13% had a minor depressive episode, 7% a major depressive episode and 6% were diagnosed with bipolar disorder. 21% of our patients were diagnosed with one or several comorbid anxiety disorders.

Most adults with ADHD are not diagnosed properly and therefore remain untreated although they are usually diagnosed and treated for comorbid psychiatric disorders. In the present study, we systematically analyzed comorbid anxiety and depression in a sample of adult ADHD outpatients in order to estimate the incidence of these disorders in an undiagnosed patient population.