ABSTRACT
Unipolar Rapid Cycling (RC) is extremely rare, and when it occurs, family history is positive for bipolar disorder. This chapter focuses on rapidcycling bipolar disorder (RCBD). RCBD has been reported in both sexes across different age groups. Studies have mostly been done at tertiary centers or clinics where patients sought treatment. Joffe et al found mean thyroid-stimulating hormone to be significantly higher in non-RC than in RC patients. Family history constitutes an important tool in validation of psychi-atric disorders. There are several published family studies of RCBD Dunner et al found similar family history in rapid cyclers compared to nonrapid cyclers. The relationship between thyroid function and affective illness has long been recognized. Hypothyroidism has been classified into grades I through III according to severity into overt, mild, and subclinical. There have been few observations addressing the type of first episode and course of episodes as they relate to RCBD.
