The behavioral high-risk paradigm and bipolar affective disorder, VIII: Serum free cortisol in nonpatient cyclothymic subjects selected by the General Behavior Inventory.

The degree of biologic concordance between bipolar affective disorder and cyclothymia was assessed within a 3-hour protocol of cortisol functioning. Cyclothymic subjects, selected by the General Behavior Inventory, showed cortisol hypersecretion approaching that of subjects with major affective disorders; they also showed poor modulation of cortisol levels over time, the degree of which was related to increased current level of depression and to a chronic, intermittent depressive course. These results not only support the validity of the General Behavior Inventory but also suggest that cyclothymic subjects with a chronic depressive course may experience persistent biologic disturbance similar to that found during episodes of major depression.