Rapid Cycling Bipolar Affective Disorder

Mark S Bauer

doi:10.1001/archpsyc.1990.01810170027005

Abstract

Thirty patients with rapid cycling bipolar affective disorder were studied prospectively to assess presence and severity of thyroid hypofunction. Seven (23%) were classified as having grade I hypothyroidism, while 8 (27%) had grade II and 3 (10%) had grade III abnormalities. This prevalence of grade I hypothyroidism is significantly greater than that reported in studies of unselected bipolar patients during long-term treatment with lithium carbonate, although only 63% of this sample of rapid cycling patients was taking lithium carbonate or carbamazepine. The association of rapid cycling with grade I hypothyroidism cannot be accounted for by lithium carbonate use or by the preponderance of women among rapid cycling patients. These findings (1) indicate that hypothyroidism during bipolar illness is a risk factor for the development of rapid cycling, and (2) leads to the hypothesis that a relative central thyroid hormone deficit occurring in bipolar patients predisposes to a rapid cycling course.

Highlights

Seven (23%) were classified as having grade I hypothyroidism, while 8 (27%) had grade II and 3 (10%) had grade III abnormalities. This prevalence of grade I hypothyroidism is significantly greater than that reported in studies of unselected bipolar patients during long-term treatment with lithium carbonate, only 63% of this sample of rapid cycling patients was taking lithium carbonate or carbamazepine
The association of rapid cycling with grade I hypothyroidism cannot be accounted for by lithium carbonate use or by the preponderance of women among rapid cycling patients. These findings (1) indicate that hypothyroidism during bipolar illness is a risk factor for the development of rapid cycling, and (2) leads to the hypothesis that a relative central thyroid hormone deficit occurring in bipolar patients predisposes to a rapid cycling course
The present study indicated that female preponderance among rapid cycling patients cannot account for the increased rates of hypothyroidism in that group

Summary

Association With Grade I Hypothyroidism

\s=b\Thirty patients with rapid cycling bipolar affective disorder were studied prospectively to assess presence and severity of thyroid hypofunction. Thyroid Axis Evaluation At entry to the study, patients and controls underwent physical examination and laboratory thyroid function assessment sufficient to assign grade I to III thyroid abnormality according to the criteria of Wenzel et al[22] or to document absence of thyroid abnormality This assessment included determination of serum levels of thyroxine (T4), triiodothyronine (T3), free T4 index, reverse Ts, and thyrotropin both basally and in response to infusion of[400] μg of protirelin. Comparison of thyroid function indices among concurrently collect¬ ed samples from rapid cycling bipolar, unipolar, and control subjects were analyzed independently by means of analysis of variance on both raw and log-transformed data, in view of the known skewness and heteroscedasticity of the neuroendocrine data in affective illness.[6] There were no differences in either set of analysis, and so results of analysis of raw data are presented here. Post hoc analyses were performed with the Bonferroni-corrected t statistic

RESULTS

III Total

CONCLUSIONS