STUDIES OF A NEUROCHEMICAL LINK BETWEEN DEPRESSION, ANXIETY, AND STRESS FROM [H-3] IMIPRAMINE AND [H-3] PAROXETINE BINDING ON HUMAN PLATELETS

We measured platelet [H-3]imipramine and [H-3]paroxetine binding in pa tients with major depression (n = 11), dysthymia (n = 9), generalized anxiety (n = 18) and panic disorder (n = 10), and in healthy controls (n = 13). The [H-3]imipramine binding capacity (B-max) was lower in al l patient groups; [H-3]paroxetine binding was reduced in anxiety disor ders, however, decreases in depression and dysthymia were not signific ant. There were no differences in the affinity constant (K-d) for eith er radioligand. We also examined the effects of examination stress on platelet binding in medical students. Compared to after vacation, when binding was similar to controls, [H-3]imipramine (n = 19) and [H-3]pa roxetine (n = 14) B-max values were significantly decreased during exa minations and similar to patient values. Examinations were also associ ated with an increase in plasma cortisol levels. These findings sugges t that there is a neurochemical link between depression, anxiety, and stress, and that disturbances in neurochemical functioning may be asso ciated with specific symptomatology, independent of psychiatric diagno sis.