Effects of Olanzapine versus Risperidone on Thyroid  Function in Schizophrenic Patients

Ibrahim M. Faisal; Imad A-J Thanoon; Mahfooth S. Al-Saydan

Volume : III, Issue : VIII, August - 2013

Effects of Olanzapine versus Risperidone on Thyroid Function in Schizophrenic Patients

Ibrahim M. Faisal, Imad A J Thanoon, Mahfooth S. Al Saydan

Abstract :

Background: Thyroid function abnormalities are relatively common in patients with psychiatric diseases especially schizophrenia, but it remains unknown if these are related to a genetic predisposition or to antipsychotic treatment. Aim: The aim of this study was to evaluate the effects of atypical antipsychotic, olanzapine and risperidone on thyroid function in a group of newly diagnosed schizophrenic patients. Method: A non–randomized design was used in this study. Subjects were recruited from an urban community mental health clinic at AL–Salam Teaching Hospital. Sixty–nine (69) patients meeting the criteria for a diagnosis of schizophrenic disorder were assigned to monotherapy with olanzapine (n=36), or risperidone (n=33). Forty (40) apparently healthy volunteers matched in age, sex and body mass index (BMI) to the patients were collected as a control group. Total triiodothyronin (tT3), total thyroxin (tT4) and thyroid stimulating hormone (TSH) were evaluated. Analysis of variance and Students t–test were used in the statistical analysis. Results: Total triiodothyronin (tT3) concentrations for control, olanzapine and risperidone groups before treatment were 1.00±0.20, 1.14±0.34, and 1.11±0.25 respectively, total thyroxin (tT4) were 7.04±1.21, 7.18±1.72 and 7.38±1.72 respectively and thyroid stimulating hormone (TSH) values were 1.26±0.69, 1.66±1.13 and 1.42±0.69 respectively, Olanzapine treatment for 8 weeks significantly decreases serum levels of tT4 at week 4 and week 8 of therapy 6.46±1.42 and 6.44±1.96 respectively, in contrast TSH serum levels significantly increased at week 4 and week 8 of olanzapine therapy 1.70±1.02 and 2.11±1.28 respectively. Therapy with risperidone only significantly increased serum levels of TSH at week 4 and week 8 of therapy 1.71±0.67 and 1.90±1.11 respectively. Conclusions: Alteration in the levels of thyroid hormones can occur in schizophrenic patients during therapy. Although routine monitoring of thyroid function in olanzapine and risperidone treated schizophrenic patients is not recommended, attention should be paid to thyroid function in such patients.