THE LIKELIHOOD OF RECURRENCE IN BIPOLAR AFFECTIVE-DISORDER - THE IMPORTANCE OF EPISODE RECENCY

These analyses used a high-intensity follow-up of of patients with bipolar affective disorder to describe the immediate and long-term risks for recurrence and the importance of sustained recovery to those risks. At the baseline evaluation, all patients were in episodes of Research Diagnostic Criteria major depressive disorder, mania or schizoaffective disorder (excluding the mainly schizophrenic subtype); those who were depressed at intake had a history of mania or schizoaffective mania. Raters re-evaluated these patients at 6-month intervals for 5 years and annually for the remainder of a 10-year follow-up. The following report describes relapse risks for the 186 patients observed to recover from their index episodes. Survival analyses quantified the likelihood of relapse over time, beginning after symptom-free periods of 4 months and 1, 2 and 3 years. Further survival analyses used treatment status as a censoring variable to estimate the eventual likelihood of recurrence among those who reported sustained compliance with lithium prophylaxis; the prophylaxis group remained under observation until they relapsed, were lost to follow-up or ceased taking lithium. Progressively longer symptom-free periods were clearly associated with lower relapse risks over the subsequent 4 years. Thereafter, however, this effect dissipitated. 7 years after recovery, the cumulative likelihood of recurrence was four in five for all bipolar patients and two in three for those whose index episode had been followed by at least 3 years without symptoms. Even with sustained lithium prophylaxis, the likelihood of at least one recurrence exceeded 70% within 5 years of recovery. The preexisting length of symptom-free periods in bipolar affective disorder can be used to predict risks for recurrence over a subsequent 4-year period. The eventual likelihood of recurrence remains quite high though, even with lithium prophylaxis.