Background. A relationship between the anticonvulsant
and
antidepressant properties of
electroconvulsive therapy (ECT) has been hypothesized. The goal of this
study
was to see whether
the anticonvulsant effects of ECT could be measured in a clinical setting
and whether there was any
relationship between the anticonvulsant effects of ECT and the
antidepressant response to it.
Methods. We examined the temporal relationship between change
in
seizure duration (as an index
of anticonvulsant activity) and improvement in Hamilton Rating Scale for
Depression scores in a
retrospective sample of 114 depressed patients who received 145 courses
of ECT.
A linear mixed
effects model was utilized for analysis so that the repeated measures nature
of the data could be taken into account.
Results. Both seizure duration and depression scores decreased
significantly through the course of
ECT. However, no evidence was found for a relationship between decrease
in
seizure duration and
clinical improvement as measured by Hamilton ratings.
Conclusions. The process underlying the reduction in seizure
duration through a course of ECT may
not be related to antidepressant efficacy.