Bauer, Mark2016-05-311990Bauer, Mark S. 1990. “Rapid Cycling Bipolar Affective Disorder.” Archives of General Psychiatry 47 (5) (May 1): 427. doi:10.1001/archpsyc.1990.01810170027005.0003-990Xhttp://nrs.harvard.edu/urn-3:HUL.InstRepos:27104241Thirty 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.en-USJournal Article2016-05-3110.1001/archpsyc.1990.01810170027005