Attention-deficit/hyperactivity disorder in adults with bipolar disorder or major depressive disorder: results from the international mood disorders collaborative project.

Objective: Relatively few studies have evaluated the clinical implications of lifetime attention-deficit/hyperactivity disorder (ADHD) in adults with bipolar disorder or major depressive disorder (MDD). Herein, we sought to determine the prevalence as well as the demographic and clinical correlates of lifetime ADHD in persons with a mood disorder.

Method: The first 399 patients enrolled in the International Mood Disorders Collaborative Project (IMDCP) were evaluated for lifetime ADHD using the Mini-International Neuropsychiatric Interview-Plus (MINI-Plus) as the primary instrument to derive current and lifetime DSM-IV diagnoses. All analyses of variables of interest were conducted utilizing the MINI-Plus, the Adult ADHD Self-Report Scale-v1.1, and the Wender Utah Rating Scale-Short Form. The effect of ADHD on clinical presentation, course of illness variables, comorbidity, anamnesis, treatment, and outcome are reported. The IMDCP is a joint initiative of the Mood Disorders Psychopharmacology Unit at the University Health Network, University of Toronto, Toronto, Ontario, Canada, and the Cleveland Clinic Center for Mood Disorders Treatment and Research at Lutheran Hospital, Cleveland, Ohio. All data for this study were procured between January 2008 and January 2009.

Results: The percentages of subjects with MDD or bipolar disorder meeting the DSM-IV criteria for lifetime adult ADHD were 5.4% and 17.6% (P < .001), respectively. Lifetime comorbid ADHD in both mood disorder populations was associated with earlier age at illness onset (MDD, P = .049; bipolar disorder, P = .005), a higher number of psychiatric comorbidities (eg, MDD and current panic disorder with agoraphobia [P = .002]; bipolar disorder and social phobia [P = .012]), and decreased quality of life (MDD, P = .018).

Conclusions: The overarching findings herein are that the adult ADHD phenotype is commonly reported by individuals with MDD or bipolar disorder and is associated with a greater illness burden and complexity.