LITHIUM AND RECURRENCE IN A LONG-TERM FOLLOW-UP OF BIPOLAR AFFECTIVE-DISORDER

Background. Though previous studies have clearly shown that lithium af fords prophylaxis in bipolar affective disorder, these studies have no t demonstrated the persistence of this prophylactic effect beyond the first year of recovery. Methods. One hundred and eighty-one patients w ith bipolar affective disorder recovered during 5 years of semi-annual follow-up. After 8 weeks of recovery, 139 were taking lithium prophyl axis and 42 were not. Analyses used drug status (lithium v. no-lithium ) as a censoring variable to compare these two groups by interval-spec ific probabilities of recurrence. Results, Recurrence was initially le ss likely in the lithium group but interval-specific probabilities of recurrence did not consistently favour either group after the first 32 weeks of recovery. Conclusions, Biases in treatment decisions may hav e both reduced the size and altered the specificity of the lithium eff ects seen here. Nevertheless, the apparent transience of lithium proph ylactic effects is unexplained and may reflect important, physiologica l differences between relapse and recurrence. This possibility invites a controlled lithium discontinuation study, with gradual taper, of pa tients who have had at least 8 months of sustained euthymia.