Factors affecting amnesia, seizure duration, and efficacy in ECT.

Twenty-nine patients given unilateral ECT were tested for memory with each treatment. Forgetting of nonverbal material correlated positively with seizure duration and with anesthetic dose. Seizure duration did not correlate with forgetting of verbal material or with changes in Hamilton depression ratings. Seizure duration was inversely related to succinylcholine and methohexital doses. These findings suggest that muscle relaxant and anesthetic doses can be adjusted to lessen the amnestic effects of ECT. There are, however, insufficient data on the relationship between seizure length and ECT efficacy to specify a minimum duration for seizures, individually or cumulatively.