Pitts' and McClure's Lactate-Anxiety Study Revisited

Abstract

Pitts and McClure (Pitts and McClure, 1967; Pitts, 1969) have recently suggested that all symptoms of anxiety and anxiety neurosis itself are caused by a raised blood and body fluids lactate level. As the biochemical mechanism underlying anxiety neurosis they proposed that the excess lactate complexes with, and reduces, the concentration of ionized calcium at the surface of excitable membranes to an extent that causes a disordered nerve activity to manifest itself in the form of anxiety symptoms. In support of this speculation, according to which anxiety neurosis is a biological disease essentially brought on by a lactate-induced hypocalcaemia, Pitts and McClure (1967) quote investigations that have shown that on standard exercise anxiety neurotics tend to produce higher blood lactate levels than do normal controls, and their own lactate infusion study. As pointed out elsewhere (Grosz and Farmer, 1969), neither the former nor the latter, however, can be considered satisfactory evidence.