Platelet imipramine binding in patients with panic disorder and major familial depression

Platelet 3H-imipramine binding was investigated in 15 normal subjects, 17 patients with major depressive disorder and 43 patients with panic disorder, to further study the relationship between depressive and anxiety disorders. Whereas patients with major depression had a significantly lower mean Bmax value than healthy volunteers, mean Bmax values in patients with panic disorder did not differ significantly from normal controls. Furthermore, apparently normal Bmax values were observed even in those panic disorder patients who had concurrent major depression or a past history of depression. Thus, despite previous findings of an overlap between panic and depressive disorders, the present results suggest that the two syndromes may have distinct neurochemical substrates.