The Effect of Sodium Amytal on Autonomic and Muscle Activity in Patients with Depressive Illness

¹ Research Psychologist, Institute of Psychiatry, Maudsley Hospital, London, S.E.5.
² Senior Registrar, Bethlem Royal Hospital; Professor of Psychiatry, University of Melbourne.

This paper deals with the effect of sodium amytal on the autonomic activity of female depressive patients. These patients were classified into three groups: endogenous, indeterminate and reactive depressives, and recordings obtained of skin resistance, heart rate, and muscle activity. In the first study, Shagass' technique of intravenous administration of sodium amytal was used to obtain sedation thresholds, but the results were not in accord with his reports of higher thresholds in reactive depressives. Autonomic activity was significantly higher after sedation than before, a finding which was attributed to the disturbing method of drug injection.

This was modified in the second study, in which the constant infusion technique was used; control groups received saline or no treatment. In addition to the three measures above, digital systolic blood pressure was recorded continuously. This was the only physiological measure which showed a significant drug effect, all the other measures showing reduced activity over time irrespective of treatment. No differential effect was observed on the different categories of depressions.