In view of these negative findings, we next evalokated a control group of patients who were still alive at follow-up. The patients comprising this group were individually and exactly matched for sex and research diagnosis (Feighner et al., 1972) with those who had died. They also were matched for age as-closely as possible and for date of admission to the hospital. When we examined the ECT experience of these living matched control patients and compared them with those of the patients who had died, we found no statistically reliable  differences (Table 1).

DISCUSSION AND CONCLUSION

The results of this retrospective study do not support the contention that ECT exerts long-term protective effects against suicide. Although not statistically significant, more of the patients whose death was ascribed to suicide had received ECT during their index hospital admission than those who died from other causes (44 vs. 32%). Similarly, when their previous ECT experience was added, more patients who died as a result of suicide had received ECT (50 vs. 40%). The matched control group revealed very similar percentages, suggesting that ECT has minimal impact on long-range survival. To consider the early studies demonstrating that ECT exerts a protective effect against suicidal death, the published data must be reworked to determine whether differences were significant. Ziskind et al. (1945) followed 200 patients for a mean of 40 months (range 6-69 months). Eighty-eight patients were treated with either Metrazol or ECT. The remaining 109 patients either refused convulsive therapy (n=43), had symptoms too mild to warrant this treatment (n=50), or had a condition contraindicating ECT (n=16). There were 13 deaths in the control patients with 9 by suicide, compared with 3 deaths with 1 suicide in the convulsive therapy patients. These data yield a Fisher's exact probability of 0.029, indicating a significant association between treatment/nontreatment and suicide/other causes of death. However, the conditions of the 16 patients with contraindications to ECT and whether they contributed disproportionately to the suicides are unknown.

Huston and Locher (1948a) compared patients with involutional psychosis untreated and treated with ECT. They found that none of the patients in the convulsive therapy group committed suicide, whereas 13% of those untreated did. Interpretation of this study is complicated by the fact that they followed the ECT-treated patients for a mean of 36 months (range 1-48 months) and the untreated patients for 77 months (range 2 days to 180 months). In a subsequent report on manic depressive psychosis treated with ECT or not, the same authors ( 1948b) found that the ECT-treated patients, followed for a mean of 36 months, had a 1% suicide rate, while the control patients, followed for a mean of 82 months, had a 7% suicide rate. Examining the association of ECT/no ECT and death from suicide/other causes yielded a nonsignificant probability using fisher's exact method. In studies of patients with involutional psychosis (Bond, 1954) and manic depressive illness (Bond and Morris, 1954) examined 5 years after treatment with ECT or no treatment, analysis of these data does not reveal a significant protective effect against suicide of ECT compared with nontreatment.

Thus, we are able to point to only one study, the very early report of Ziskind et al. (1945), which indicates a significant protective effect of ECT against suicide. The remainder of the evidence is overwhelmingly negative. It appears to us that the undeniable efficacy of ECT to dissipate depression and symptoms of suicidal thinking and behavior has generalized to the belief that it has long-range protective effects. In one sense, it is reassuring that this very effective somatic therapy does not exert long-reaching influences on future behavior, in another, it is disappointing that it does not.

Acknowledgment: This work was supported in part by a grant from the Association for the Advancement of Mental Health Research and Education. Inc., Indianapolis. IN 46202. U.S.A.

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