[Electroconvulsive therapy and benzodiazepine: antagonism or indifference? Review of the literature].

BACKGROUND

It is usually considered that the efficacy of electroconvulsive therapy is due to the induction of a seizure (20). Benzodiazepines are well known antiepileptics (11) and it is suggested that they should be withdrawn during electroconvulsive therapy (3). The purpose of our study was to determine the evidence that exists for this hypothesis in the literature.

METHOD

We have reviewed the international literature on electroconvulsive therapy and benzodiazepines through the Medline and Pascal reference database, and performed a manual search of the major international journals. We have retained the references dealing with both benzodiazepine and electroconvulsive therapy.

RESULTS

Up to June 1990, 16 references have been found (table I). Of these 16 references, 5 (6, 7, 12, 19, 25) are letters to the editor with no data reported. Six papers (1, 2, 8, 9, 14, 22) examine benzodiazepines as anesthetics and only focus on anesthetic variables, ignoring electroconvulsive therapy-treatment outcome. Only four studies (5, 17, 23, 24) actually examine the incidence of benzodiazepine use on electroconvulsive therapy. Of these, three studies (17, 23, 24) report the incidence of benzodiazepines used as tranquilizers or hypnotics on duration of the electroconvulsive therapy induced seizure. One is a retrospective study (24) showing a decrease in seizure duration due to benzodiazepine use. Of the two prospective studies one shows (23) no difference in seizure duration and the other one (17) a decrease. These studies, however, fail to actually examine how the antidepressive efficacy of electroconvulsive therapy is modified by benzodiazepine use. One recent study (5) measures the antidepressive efficacy of electro-convulsive therapy through the decrease of a validated depression scale. This is a randomized double-blind study examining a short acting benzodiazepine used as an anesthetic in lieu of methohexital. Electroconvulsive therapy efficacy does not appear impaired.

CONCLUSION

From our review of the literature it appears that the supposed negative effect of benzodiazepines on the antidepressive action of electroconvulsive therapy has not been demonstrated. Further studies are necessary warranted.