Pretreatment Thyroid Profile and its Relationship with Response to Treatment with Lithium in Bipolar Mood Disorder: A Longitudinal Study from Northeast India

Abstract

Abstract Background: The thyroid hormone’s significant impact on the treatment of depressive and other mood disorders is well documented. Even minor hypothyroidism can modify the progression and treatment results of major depressive disorder. This research aims to explore the correlation between initial thyroid levels and the treatment outcome in bipolar mood disorder using lithium, a well-established treatment method. Methodology: The study involved 45 bipolar mood disorder patients diagnosed according to the Diagnostic and Statistical Manual 5 criteria and admitted to a tertiary care teaching institute in Northeast India. The patients received lithium treatment, with injectable lorazepam used for immediate agitation control when necessary. On the 1st day, a semi-structured questionnaire and Brief Psychiatric Rating Scale (BPRS) 24-item scale were used to evaluate symptoms, and samples were collected for a thyroid profile, including T3, T4, FT3, FT4, and thyroid-stimulating hormone (TSH). The BPRS scale was used again on the 30th day to assess treatment response. Results: The BPRS subscale showed the highest treatment response for grandiosity and the lowest for depression. Factors such as age, illness duration, substance use, and family history of mood disorder were inversely correlated with the BPRS score’s decrease. Initial thyroid levels were identified as a predictor of treatment response, with baseline T4 levels showing a significant positive correlation with treatment response, while baseline TSH levels showed a negative correlation. Conclusion: Lithium proved to be an effective treatment for bipolar mood disorder, particularly for the manic subtype. Initial T4 and TSH levels were found to significantly predict treatment response, with T4 showing a positive correlation and TSH showing a negative correlation.