ECT Stimulus Duration and Its Efficacy

AbstractIn a consecutive series of 21 men who received a course of brief-pulse square-wave electroconvulsive therapy (ECT), a 2-second train of pulses led to a significantly (p < 0.001) higher rate of success in inducing a full seizure than a 1-second train of pulses (52.4% success) of the same electrical charge. This result held whether the train was increased to 2 seconds by shortening pulsewidth from 1.5 msec to 0.75 msec (95.2% success, p < 0.001) or by decreasing frequency from 60 to 30 pulse-pairs per second (85.7% success, p < 0.01). With an ECT stimulus of electrical charge near the human average seizure threshold, a 2-second stimulus duration is more efficient than a 1-second stimulus duration. These results also indicate that expression of seizure threshold in terms of stimulus charge and voltage is incomplete.