LONG-TERM OUTCOME OF LITHIUM PROPHYLAXIS IN BIPOLAR DISORDER - A 5-YEAR PROSPECTIVE-STUDY OF 402 PATIENTS AT A LITHIUM CLINIC

Objective: In this prospective study, information was collected on all bipolar I patients who started lithium prophylaxis at a lithium clini c during more than 15 years. Method: Patients were evaluated bimonthly with standardized instruments for as long as they took lithium. Treat ment surveillance conformed to internationally accepted guidelines. Fi ve years after starting prophylaxis, each patient was contacted for a follow-up interview. Results: Of the 402 enrolled patients, 27.9% were no longer taking lithium at follow-up; 38.1% were taking lithium and had had at least one recurrence of the disorder; and 23.4% were taking lithium and had had no recurrence. Among patients still taking lithiu m whose plasma lithium levels had been below 0.5 mmol/liter on no more than 10% of checks, 88.0% had at least it 50% reduction in mean annua l time spent in the hospital compared to a reference pretreatment peri od, and 43.0% had had no recurrence. Patients not taking lithium at fo llow-up had a poorer outcome than those taking lithium, but patients n o longer taking any psychotropic drug did not differ from those taking lithium. Patients pro longer taking lithium had had a higher frequenc y of psychotic features in the index episode than those still taking l ithium. Conclusions: The impact of lithium prophylaxis on the course o f bipolar disorder is severely limited by the high dropout rate. In bi polar patients taking lithium regularly for several years, a drastic r eduction of time spent in the hospital is almost the rule; these patie nts represent a self-selected population in which at least one group a t high risk of poor outcome is under-represented.