Typology of clinical course in bipolar disorder based on 18-month naturalistic follow-up.
BACKGROUND
Individual variation in the clinical course of bipolar disorder may have prognostic and therapeutic implications but is poorly reflected in current classifications. We aimed to establish a typology of the individual clinical trajectories based on detailed prospective medium-term follow-up. Method Latent class analysis (LCA) of nine characteristics of clinical course (time depressed, severity of depression, stability of depression, time manic, severity of mania, stability of mania, mixed symptoms, mania-to-depression and depression-to-mania phase switching) derived from life charts prospectively tracking the onsets and offsets of (hypo)manic, depressive, mixed and subsyndromal episodes in a representative sample of 176 patients with bipolar disorder.


RESULTS
The best-fitting model separated patients with bipolar disorder into large classes of episodic bipolar (47%) and depressive type (32%), moderately sized classes characterized by prolonged hypomanias (10%) and mixed episodes (5%) and five small classes with unusual course characteristics including mania-to-depression and depression-to-mania transitions and chronic mixed affective symptoms. This empirical typology is relatively independent of the distinction between bipolar disorder type I and type II. Lifetime co-morbidity of alcohol use disorders is characteristic of the episodic bipolar course type.


CONCLUSIONS
There is potential for a new typology of clinical course based on medium-term naturalistic follow-up of a representative clinical sample of patients with bipolar disorder. Predictive validity and stability over longer follow-up periods remain to be established.
Department of Psychiatry, Dalhousie University, Halifax, NS, Canada. rudolf.uher@kcl.ac.uk
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Uher
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Mantere
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Suominen
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Isometsä
D000328:Adult; D019973:Alcohol-Related Disorders / Q000453:epidemiology; D001714:Bipolar Disorder / Q000145:classification* / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D018450:Disease Progression; D005260:Female; D005387:Finland; D005500:Follow-Up Studies; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D015233:Models, Statistical; D011569:Psychiatric Status Rating Scales; D012008:Recurrence; D012720:Severity of Illness Index; D013997:Time Factors