Biphasic course in bipolar II outpatients: prevalence and clinical correlates of a cyclic pattern described by Baillarger and Falret in hospitalised patients in 1854.

BACKGROUND

Biphasic course refers to a mood episode immediately followed by one of opposite polarity and then usually by a free interval. It was described under the rubric of folie à double forme among psychiatric inpatients by the French psychiatrist Baillarger 150 years ago. A rapid cycling form (folie circulaire) was also described in the same year by his compatriot Falret. These patients would probably have today met the criteria for bipolar I. Our aim was to find the prevalence and clinical correlates of biphasic course in bipolar II (BP II) in contemporary ambulatory patients.

METHODS

Consecutive 206 BP II outpatients were interviewed in the first author's private practice, using a modified Structured Clinical Interview for DSM-IV. To assign a patient to biphasic episode, it must have occurred at least once when not on an antidepressant.

RESULTS

Frequency of biphasic course was 80%. Biphasic vs. non-biphasic course was significantly higher in polyepisodic major depressive episode (MDE) and those with antidepressant-associated hypomania; the same was true for index melancholic subtype, where index of Global Assessment of Functioning scale (GAF) score was lower. Female gender, age at onset, mixed depressive episodes and bipolar family history were not significantly different between the two groups.

LIMITATIONS: Patients were not observed on a prospective basis. We cannot report on the relative proportion of MDE preceded vs. followed by hypomania, because such distinction was not part of FB's naturalistic database.

CONCLUSIONS

Strikingly in line with Baillarger's observation 150 years ago, biphasic course represented the typical pattern in this outpatient private practice sample of BP II. That antidepressant-associated hypomania was significantly more common in the biphasic course variety suggests that when MDE preceded hypomania-in such patients, antidepressants might have simply accentuated the natural cycle rather than causing it. Switching in the clinical setting then seems to depend on a biphasic cyclic baseline aggravated by antidepressant use. The fact that mixed states were equally prevalent in both course patterns suggests that the mechanisms involved in switching and mixity may be distinct. The significantly higher number of melancholic episodes with lower GAF scores indicates that-in line with Falret's description-overall, the biphasic course represents a relatively unfavorable outcome pattern.