ADHD is characterized by a continuous history of hyperactivity, forgetfulness, distractibility, impulsiveness and/or inattention, starting from the early childhood and at a more severe extent than whatever may be usual in peers. Originally described in pediatric populations, it is widely recognized in adults. While the disorder in children is mostly described as a disorder involving hyperactivity and impulsiveness, in adulthood ADHD inattention prevails on externalizing features, with a higher rate of psychiatric comorbidities, including major depressive disorder, bipolar disorder (BD), anxiety disorders and substance abuse (SUD).
Co-morbidity among ADHD, SUD and BD has been reported in many clinical and epidemiological studies. For this purpose we evaluated the prevalence of symptoms belonging to the ADHD spectrum in two samples of adult patients affected by SUD and by BD.
We found that one fifth of our sample of bipolar adults has a current diagnosis of ADHD, and that these patients are characterized by a greater number and more severe depressive episodes, resulting in a marked interference in global adaptation, when compared with ADHD subjects without bipolar. To complicate the clinical picture in BD + ADHD group, they are often associated with the Substance Use Disorder and the Impulse Control Disorder. Dual Diagnosis (BD+SUD) patient out of 4 reported childhood history of ADHD and more than 1 patient out of 2 presented corresponding symptoms at the time of observation. Our data are consistent with the observation that SUD in ADHD patients features an earlier onset, a longer duration and a faster progression towards substance polyabuse. In addition, the risk for developing a SUD is increased by the comorbidity of ADHD and BD. Our study confirms the observation that the relationship between adult ADHD and Substance Use Disorder is conveyed by the association with conduct disorders and antisocial personality disorder. Our data are consistent with the hypothesis that this relationship may also be facilitated by the presence of Bipolar Disorder. In conclusion, Bipolar Disorder, ADHD, Conduct Disorder and Substance Use Disorder may share a common diathesis conveyed by hyperactivity-impulsivity. Further prospective studies are needed to confirm our observations and to evaluate the influence of ADHD symptoms on course and treatment response.