After an initial improvement following electroconvulsive therapy, the study shows that there is a high degree of relapse, mostly during the first six months. This is in line with the results of other studies
(3). In the case of three patients, a relapse did not occur until after 5 – 11 years, which influenced the average time to relapse.
The findings support the assumption that the sub-diagnosis of affective disorder is positively associated with the risk of relapse. In the small group with first-time depression, seven of ten improved after electroconvulsive therapy and none relapsed, whereas relapse was frequent in cases of recurrent depression and bipolar depression. It appears that age may be of significance when it comes to time to relapse (Table 1). Only one of six 40-year-olds suffered a relapse in the course of the first six months, even though none of them had first-time depression (data not shown).
The patient group had a high degree of medication resistance, which may have contributed to relapses. Almost half had used two or more classes of antidepressants before the ECT series, but this does not appear to have influenced the relapse rate or the median time to relapse. Sackeim et al. found a higher relapse rate among those who had received appropriate pre-ECT pharmacotherapy than among those who had not received it – 64 % compared with 32 %
The high relapse occurrence may be related to the fact that 18 % of the patients who improved did not receive prophylactic medicines after the first ECT series, and that most of those who received secondary prophylaxis received antidepressants that had already proved ineffective against depression before the ECT treatment (data not shown). Those who received a combination of an antidepressant and lithium and/or a neuroleptic exhibited a lower relapse rate and longer median time to relapse than those who received an antidepressant alone.
The relapse percentage for the 100 follow-up ECT series that 46 patients received was somewhat higher. The explanation may be that 93 of these series concerned recurrent or bipolar depression (data not shown).
What can be done to maintain remission over time? In a recent overview it is found that psychotherapy alone or in combination with antidepressants or electroconvulsive therapy may have a positive supplementary effect, but that this is not a robust strategy for preventing relapse
Many clinics now administer maintenance ECT to extend the remission period and reduce the need for rehospitalisation when medicinal treatment has failed to prevent relapse
(7). In a controlled retrospective study, it was found after two years that 93 % had suffered no serious relapse with maintenance ECT in addition to a combination of medicines, compared with 52 % without maintenance ECT. After five years, the figures were 73 % and 18 % (8).
Lisanby et al. propose that prophylactic antidepressant medicinal treatment be started already during the ECT series, and that four ECT treatments be given during the first month after the series, since the risk of relapse is greatest then
(9). Thereafter patients should be examined weekly to determine the treatment frequency for the next six months. This approach should be tested with a randomised, controlled trial.
Strengths and weaknesses
Strengths and weaknesses
Strengths and weaknesses have been discussed previously
(1) and are summed up briefly here. The material consists of a selected patient group and is based on retrospectively obtained case notes. Although patients were as a rule monitored during aftercare and rehospitalised in the same department on relapse, it is not certain that all relapses were recorded. The information in the patients’ records was not good enough to enable assessment of whether antidepressants were administered in an optimal dose over an appropriate period of time, or to establish the degree of compliance of this treatment. Lack of compliance may be part of the explanation for the high relapse frequency.
Multivariable analyses were not performed or tested for possible confounding factors. The sub-groups in the material were small, which makes comparisons uncertain. The strength of the study is its naturalistic form and the fact that it spans a long period of time.