Distinguishing young people with emerging bipolar disorders from those with unipolar depression.

BACKGROUND: To facilitate early intervention, there is a need to distinguish unipolar versus bipolar illness trajectories in adolescents and young adults with adult-type mood disorders.
METHODS: Detailed clinical and neuropsychological evaluation of 308 young persons (aged 12 to 30 years) with moderately severe unipolar and bipolar affective disorders.
RESULTS: Almost 30% (90/308) of young people (mean age=19.4±4.4yr) presenting for care with affective disorders met criteria for a bipolar-type syndrome (26% with bipolar I). Subjects with bipolar- and unipolar-type syndromes were of similar age (19.8 vs. 19.2yr) and reported comparable ages of onset (14.5 vs. 14.3yr). Clinically, those subjects with unipolar and bipolar-type disorders reported similar levels of psychological distress, depressive symptoms, current role impairment, neuropsychological dysfunction and alcohol or other substance misuse. Subjects with unipolar disorders reported more social anxiety (p<0.01). Subjects with bipolar disorders were more likely to report a family history of bipolar (21% vs. 11%; [χ(2)=4.0, p<.05]) or psychotic (19% vs. 9%; [χ(2)=5.5, p<.05]), or substance misuse (35% vs. 23%; [χ(2)=3.9, p<.05]), but not depressive (48% vs. 53%; χ(2)=0.3, p=.582]) disorders.
CONCLUSIONS: Young subjects with bipolar disorders were best discriminated by a family history of bipolar, psychotic or substance use disorders. Early in the course of illness, clinical features of depression, or neuropsychological function, do not readily differentiate the two illness trajectories.