Factors influencing seizure duration and number of seizures applied in unilateral electroconvulsive therapy. Anaesthetics and benzodiazepines.

A certain minimum in the duration of seizures appears to be a condition for a satisfactory therapeutic effect in ECT. The aim of the present investigation is to elucidate the importance of some factors which may influence the seizure duration. In a controlled double-blind investigation with crossover, carried out on 19 patients, thiopentone and methohexitone were compared as anaesthetics for unilateral ECT. No differences were found between the anaesthetics regarding duration of seizures, number of treatments with insufficient seizures duration or amount of energy applied. Blood pressure measured after the seizure was slightly higher with thiopentone than with methohexitone and methohexitone as anaesthetic for ECT. In a retrospective investigation concerning seizure duration in unilateral ECT, patients given benzodiazepines during the treatment period were compared with patients who received no such medication. The benzodiazepine group showed shorter seizure duration, more cases with insufficient seizure duration and a need for a greater number of treatments. Benzodiazepines should be administered with caution during ECT, as they can impair the efficacy of treatments and consequently prolong the treatment period.