The current report contributes to the limited literature on follow-up evaluations of community-based patients in developing countries. Further, this sample offered the opportunity to study the course of bipolar disorder little affected by prophylactic pharmacotherapy. The mean number of episodes/year,1,3,16
and the occurrence of sub-threshold symptoms17
are similar to reports from developed countries.
Studies from the USA2,16
have reported that 19–28% of patients remain relapse-free over a 4–5-year period, and 11% of subjects had not relapsed during another 10-year follow-up evaluation.3
Five patients in this study had experienced only a single manic episode. It is possible that some bipolar patients relapse only after extended periods, and it would be worthwhile attempting to identify the determinants of such long cycles.
Consistent with other similar reports, this study also found an over-representation of mania. Interestingly, this pattern of course among bipolar patients has been reported mostly from the tropical regions, such as Nigeria,7
Is it possible that bright sunlight and a less variable day–night cycle could result in more manic episodes in the tropics? This, however, contrasts with reports from the temperate regions, where bipolar patients may experience depression for about a third of their course.4,17
Limitations of this study include the small number of patients followed, and consequently the results should be considered preliminary. Next, given logistic difficulties, we were unable to perform frequent structured evaluations. We attempted to overcome this by integrating information from multiple sources so that the data were as complete and thorough as possible. Nonetheless, in spite of all efforts, it is possible that some episodes were missed. Another possibility is that inadvertently, we examined subjects that mainly began their illness with mania, and recent evidence suggests that mood state at study entry might predict the polarity of future relapse.18
Finally, the results may be applicable to rural but not urban areas, where factors known to influence relapse, such as stress, are different.
The study strengths include the community-based nature of subjects. A range of relapse frequencies characterizes the course of bipolar disorder in rural south India and the influence of treatment on outcomes in a similar but larger group warrants further exploration.