Individual differences in plasma cortisol changes during mania and depression.

Daytime plasma cortisol levels in four rapid cycling bipolar affective disorder patients were measured longitudinally over multiple affective episodes, and changes in levels with mood state assessed for each individual patient. While three of the four patients had, as expected, increased cortisol levels during depression, higher cortisol levels were also found in the days immediately preceding depressive episodes. Daytime cortisol levels in mania were more variable but were lower in mania for two of the patients. It is hypothesized that in the early stages of mania decreased cortisol levels reflect early neurochemical changes, but that, as manic episodes become dysphoric and/or severe, elevated cortisol levels occur.