Low-dose clozapine therapy for a bipolar patient with abnormal levels of thyroid function and anti-thyroid antibodies.

The relationship between mood disorders and abnormalities of the endocrine and immune systems have been described (Horning et al. 1998, Kanba et al. 1998). Thyroid abnormalities associated with lithium treatment have been widely reported, including goiter, hypothyroidism, hyperthyroidism, and autoimmune thyroiditis (Kibirige et al. 2013). The presence of antithyroid antibody titers in bipolar patients has also been associated with hypothyroidism, particularly in patients undergoing lithium therapy (Chakrabarti 2011). Many studies that investigated whether anti-thyroid peroxidase antibodies are associated with lithium exposure had produced contradictory findings. Kupka et al. (2002) suggested that an increased incidence of anti-thyroid antibodies was found in bipolar patients prior to treatment compared to the general population and is not associated with lithium treatment. Clozapine has been used in the treatment of bipolar disorder for many years (Chang 2006). So far there are many hypotheses regarding the effect of clozapine in mood disorder. Here we report a bipolar patient receiving long-term treatment. She was initially prescribed lithium treatment but in vain. Two years after taking low-dose clozapine, her manic symptoms resolved and hypothyroidism improved without any detectable antithyroid antibody.