A Systematic Review of Rates and Diagnostic Validity of Comorbid Adult Attention-Deficit/Hyperactivity Disorder and Bipolar Disorder

Objective: Adult attention-deficit/hyperactivitydisorder (ADHD) is increasingly recognized andreported to frequently coexist with bipolar disorder.Concurrent diagnosis of adult ADHD andbipolar disorder remains controversial. In thisstudy, we conducted a systematic review to examinethe rates and diagnostic validity of the conceptof comorbid adult ADHD and bipolar disorder.

Data Sources: MEDLINE, Embase, PsycInfo,and Cochrane databases were searched for articlespublished before March 30, 2007, using the keywordsmanic, bipolar, attention deficit hyperactivity,and adult. The computer search was supplementedwith bibliographic cross-referencing.

Study Selection: Exclusion criteria werestudies with only pediatric subjects, childhoodADHD only but not adult ADHD, and eitherbipolar disorder or ADHD only, but not both;review articles, case reports; letters to the editor;and book chapters. Of the 262 citations found,12 studies met our inclusion criteria.

Data Extraction: Specific diagnosticvalidating criteria examined were phenomenology,course of illness, heredity, biological markers,and treatment response. There were 6 studieson comorbid rates, 4 on phenomenology, 3 oncourse of illness, 2 on heredity, none on biologicalmarkers, and 1 on treatment response.

Data Synthesis: The proposed comorbid syndromeis fairly common (present in up to 47% ofadult ADHD and 21% of bipolar disorder populations),with a more severe course of illness comparedwith that of bipolar disorder alone, and highrates of comorbidity with other psychiatric disorders.Its treatment appears to require initial moodstabilization.

Conclusions: Comorbid adult ADHD andbipolar disorder has been insufficiently studied,with more emphasis on comorbidity rates andfew data on course, neurobiology, heredity, andtreatment. The diagnostic validity of adult ADHD/bipolar disorder as a true comorbidity is not wellestablishedon the basis of this equivocal and insufficientliterature. More studies are greatlyneeded to further clarify its diagnostic validityand treatment approach.’ ‹