OBJECTIVE: The longitudinal course of 51 patients with treatment-
refractory bipolar disorder was examined to assess possible effects of
heterocyclic antidepressants on occurrence of manic episodes and cycle
acceleration. METHOD: Using criteria established from life charts,
investigators rated the patients' episodes of mania or cycle acceleration
as likely or unlikely to have been induced by antidepressant therapy.
Discriminant function analyses were performed to assess predictors of
vulnerability to antidepressant-induced mania or cycle acceleration.
Further, the likelihood of future antidepressant- induced episodes in
persons who had had one such episode was assessed. RESULTS: Thirty-five
percent of the patients had a manic episode rated as likely to have been
antidepressant-induced. No variable was a predictor of vulnerability to
antidepressant-induced mania. Cycle acceleration was likely to be
associated with antidepressant treatment in 26% of the patients assessed.
Younger age at first treatment was a predictor of vulnerability to
antidepressant-induced cycle acceleration. Forty-six percent of patients
with antidepressant-induced mania, but only 14% of those without, also
showed antidepressant- induced cycle acceleration at some point in their
illness. CONCLUSIONS: Mania is likely to be antidepressant-induced and not
attributable to the expected course of illness in one-third of
treatment-refractory bipolar patients, and rapid cycling is induced in
one-fourth. Antidepressant-induced mania may be a marker for increased
vulnerability to antidepressant-induced cycle acceleration.
Antidepressant-induced cycle acceleration (but not antidepressant- induced
mania) is associated with younger age at first treatment and may be more
likely to occur in women and in bipolar II patients.