Clinical factors associated with lithium treatment response in bipolar disorder patients from India.

Background: Bipolar Disorder (BD) is a chronic and disabling psychiatric illness with waxing and waning course. Lithium is the mainstay of treatment for Bipolar disorder (BD). There is limited literature on the clinical markers of Lithium treatment response from south Asia.

Methods: Two hundred and ten individuals with BD I and a history of at least 6 months of treatment with Lithium were recruited from the outpatient services of the National Institute of Mental Health and Neurosciences (NIMHANS) after obtaining informed consent. A diagnosis of BD I was made according to the DSM-IV criteria. The characterization of response to lithium prophylaxis was done using NIMH Retrospective Life Chart and "Retrospective Criteria of Long Term Treatment Response in Research Subjects with Bipolar Disorder" scale.

Results: There were 132 (62.86%) good responders and 78 (37.14%) non-responders. Good responders were noted to have less number of hospitalizations and more onset episode of depression than non-responders. Using continuous phenotype, Lithium response was inversely correlated with total number of episodes, number of episodes of mania/ depression, number of hospitalisations and presence of suicide attempt. Multivariate analysis only revealed number of episodes and hospitalization to be associated with Lithium response.

Conclusion: Our Lithium response rates were higher than what have been reported in the few previous studies. Illness severity was the only factor associated with Lithium response. There is a need to examine this question in larger prospective samples and to focus on biological/ molecular markers of treatment response.