The effect of electro-convulsive therapy on the psycho-galvanic response.

THOUGH electro-convulsive therapy (E.C.T.) is one of our most useful treat ments, its mode of action is still largely unknown, and this ignorance is preventing us from making it more successful and more widely applicable. Among its possible modes of action is the possibility of its having some “¿ activating― action on the basal, and more particularly on the hypothalamic, structures. Such activation might be expected to show in the psycho-galvanic response (P.G.R.), and we have therefore investigated something of the relationship between them. Many of the facts that would justify this investigation need not be given here as they have been reviewed in previous publications (Ashby and Bassett, 1950; Ashby, 1952(b)). Knowledge of the effect of E.C.T. on the P.G.R. may at least help in establishing a primary orientation in the question of how E.C.T. acts thera peutically; for at present the possibilities range from an action by some shock like effect on the pituitary and other endocrines, through events in the psycho analytic mechanisms, to a randomly distributed effect on the cerebral cortex, forcing disorganization and subsequent re-integration (Roth, 1952; Ashby, 1952(a)). Study of its effect on the P.G.R. may help to give such an orientation, and we decided therefore to follow the P.G.R. over the weeks of treatment, particularly with the aim of seeing whether the treatment would lead to any sustained increase in the patient's responsiveness. Since we wished to follow the P.G.R. over some weeks, and therefore wished to get as smooth a curve as possible, we decided not to evoke the response by the use of emotionally toned words, since their effects might by expected to fluctuate widely, but to use more or less direct physical stimuli whose properties could be controlled within narrow limits. We therefore used such stimuli as a flash of light to the eye. We wished, however, to explore something of the subject's “¿ higher― eactions to his environment, so we decided also to test his response to the merely threatened application of the physical stimulus, bringing the lamp into position but not making it flash. Various stimuli were used, as will be described below. It was clear that the chief difficulty in the interpretation of the results would lie in assessing the effect of habituation—the universal tendency of the reacting organism to react less and less as a series of non-injurious and repetitive stimuli are given. Repetition there had to be, for the later results must be comparable with the earlier.