Current Control in Electroshock Therapy. ∗

Abstract

Electroshock treatment consists in the passage of alternating current for a few tenths of a second through electrodes placed on the temples of the patient. The intensities of the current vary from 200 milliamperes to the neighborhood of 1,000 milliamperes. The customary procedure is to apply a certain voltage obtained from the general alternating supply line. If the resistance of the head of the patient could be determined in advance, the current which would flow for a given voltage could be predicted. It is known that this is not the case. The patient's head resistance is variable and unpredictable. A test measurement of resistance with a small current gives high values (roughly from 500 to 5000 ohms) which are not correlated with the resistances actually offered to the large shock current. The resistances for the large shock currents also show appreciable variation, not only from patient to patient, but also in the same patient at different times. For electrodes of 15-25 cm² in area, these resistances vary from about 100 to 300 ohms. It is clear that the application of a given voltage to the electrodes will give fluctuating and uncontrollable values for the shock current (Table I). Of the two factors which determine the effect of the shock, the duration of the current, and the strength of the current, the first is readily controlled by means of a suitable timer; it is, however, just as essential to control the second factor. The physical conditions of the shock would then be fixed, and could be prescribed in advance.

An electroshock apparatus which gives a preassigned current to the patient regardless of the resistance has been designed and constructed in our laboratories, and is now in satisfactory operation at the Patton State Hospital, Patton, California.