Can adults with attention-deficit/hyperactivity disorder be distinguished from those with comorbid bipolar disorder? Findings from a sample of clinically referred adults

Background Despite data describing the overlap of attention deficit hyperactivity disorder (ADHD) and bipolar disorder (BPD) in youth, little is known about adults with these co-occurring disorders. We now evaluate the clinical characteristics of referred adults with (n = 24) and without BPD (n = 27). Methods Referred adults to clinical trials of ADHD were evaluated by psychiatric evaluation using DSM-IV criteria. Structured psychiatric interviews were used to systematically assess adult and childhood disorders. Results The vast majority of patients with ADHD plus BPD had bipolar II disorder (88%). Adults with ADHD plus BPD had higher rates of the combined subtype of ADHD compared to ADHD without BPD (χ2 = 8.7, p = .003), a greater number of DSM-IV ADHD symptoms (14.8 ± 2.9 and 11.4 ± 4.0; t = −3.4, p< .01), more attentional symptoms of ADHD (8.1 ± 1.4 and 6.8 ± 2.1; t = −2.5, p< .02; trend), poorer global functioning (47 ± 5.9 and 52 ± 7.4, t = 2.6, p< .02; trend), and additional comorbid psychiatric disorders (3.7 ± 2.5 and 2.0 ± 1.9; t = −2.9, p< .01). Conclusions These results suggest that adults with ADHD plus BPD have prototypic symptoms of both disorders, suggesting that both disorders are present and are distinguishable clinically.