ADHD and Bipolar Disorder in Adulthood: Clinical and Treatment Implications

Attention deficit hyperactivity disorder (ADHD) is a condition that usually has its onset in childhood. Although the disorder persists into adulthood in half of cases, adult ADHD is often not recognized due to different psychopathological characteristics, quite often overlapping with other diagnoses such as mood, anxiety and personality disorders. This is especially true for bipolar disorder (BD), which shares several symptoms with adult ADHD. Moreover, besides an overlapping clinical presentation, BD is often co-occurring in adults with ADHD, with comorbidity figures as high as 20%. This review will focus on the comorbidity between ADHD and BD by exploring the magnitude of the phenomenon and evaluating the clinical and functional characteristics associated with ADHD–BD comorbidity in adults. Finally, the review will address the implications of pharmacologically treating the ADHD–BD comorbidity, providing suggestions in how to treat these complex patients and addressing the issue of treatment-induced manic switch with the use of stimulants and other medications for ADHD.