A Follow-up of 1076 Patients with Major Affective Disorders

Donald W. Black, M.D., M.S.
George Winokur, M.D.
Emmanuel Mohandoss, M.S.
Robert F. Woolson, Ph.D.,
and Amelia Nasrallah, M.A.

Ann Clin Psych 1989;1:165-173

This article reports mortality risk among 1076 Iowans with major affective disorders (705 primary unipolar, and 152 bipolar depressives) compared to that of the general population. Patients were divided into four treatment groups depending on primary mode of therapy during the index admission; the groups included electroconvulsive therapy, adequate antidepressants, inadequate antidepressants, and neither treatment. All patients in the sample had an increased risk for an early death. A high risk for suicide was found for patients within each individual treatment group during the follow-up, especially the first 2 years when 69.4% (n=25) of total suicides occurred. There were no significant differences in the risk for suicides, or deaths from all causes combined, among patients in the four treatment groups. Furthermore, mortality did not differ between patients having a lifetime history of ECT and patients never having had ECT. We conclude from a short-term follow-up of depressives that mode of therapy received in the hospital has minimal influence on subsequent mortality, including suicide.

Do modern psychiatric treatments help prevent suicide? These provocative questions have been asked repeatedly since effective treatments for the major psychiatric illnesses were developed beginning with electroconvulsive therapy (ECT). Few answers have been provided. Although several early studies on convulsive therapies (ECT or metrazol) were encouraging [1-3], other reports were not. More recently, two studies found lower death rates in depressives [6] and schizoaffectives [7] treated with ECT, but suicide rates were unchanged. Three additional studies since 1976 have not shown ECT to reduce suicide rates in depressives, either [8-10].

Confounding the effect of somatic treatment on death rates has been the independent trend in general mortality and suicide rates. In the past, both natural and unnatural causes of death were highly excessive [11, 12, 14], but now death from suicides and accidents is primarily responsible for the excess [13, 14]. Death from natural causes in psychiatric patients has been declining, however, most likely due to improvements in the availability and efficacy of general medical care, and deinstitutionalization, and may no longer be excessive [11, 13, 15]. Because natural causes of death may no longer be excessive, any protective effect that ECT may have had in the past in these deaths may now be unimportant. Any effect that ECT might have on preventing suicide could still be critical, however. Also of concern is whether antidepressants, particularly tricyclics, might actually increase death rates, due either to their demonstrated effects on vascular and cardiac conduction at both therapeutic and supratherapeutic dosages [16, 17].

We adjusted for length of follow-up because study subjects were not all followed for the same amount of time. For example, a person followed 10 years would have a greater cumulative risk for mortality than someone followed 1 year. This method is more fully described elsewhere [22].

Expected and observed numbers of deaths were compared using the Freeman-Tukey-corrected chi square. The Freeman-Tukey correction was used because it is more conservative than the regular chi square and many of our expected numbers were so small. Standardized mortality ratios (SMRs) were calculated and represent the ratio of observed to expected mortality. An SMR greater than I means that observed death exceeds expectation. Ninety- five percent confidence limits were calculated for the SMRs using Byar's method [26].

RESULTS

Of 1076 patients, 372 (34.6%) received ECT, 180 (16.7%) received adequate antidepressants, 317 (29.5%) received inadequate antidepressants, and 207 (19.2%) received neither ECT nor antidepressants during the index hospitalization. Using a four-way chi square, there were significant differences among the groups on age, marital status, prior episodes, prior suicide attempts, precipitating factors, delusions, and recovery at discharge. There were no differences in sex or suicidal ideations. Patients receiving ECT were older than the others, were more likely to be married (probably because of their advanced age), tended to have more delusions, and were less likely to have attempted suicide. Patients within the two antidepressant groups were similar except that patients receiving adequate antidepressants were more likely to have had prior episodes of illness. The group of patients receiving neither treatment differed from the other groups. These patients were younger, were less likely to be married, nearly two thirds had reported factors precipitating their depressions, nearly one-half had prior suicide attempts, and few were reported as receiving drug prophylaxis. At hospital discharge, patients receiving ECT were more likely to have recovered than patients in the other treatment groups.

Thirty-six suicides were identified in the record-linkage and comprise 3.3% of the study sample (Table 1). The following percentage of the total sample size for each diagnostic group committed suicide: ECT 3.2, adequate antidepressant 2.8, inadequate antidepressant 3.5, and neither treatment 3.9. There were no significant differences for the unadjusted (crude) suicide rates among the treatment groups (x2=0.944, df=3). Suicides as a percentage of the total deceased were ECT 23.5, adequate antidepressant 33.3, inadequate antidepressant 50.0, and neither treatment 53.3.

Table 2 shows the distribution of the 103 deaths by treatment group and portion of follow-up. Forty (38.8%) deaths occurred during the first 2 years of the follow-up. During this portion of the follow-up, general (all cause) mortality was significantly excessive compared with expectation for the groups receiving ECT and inadequate antidepressants. For the entire follow-up period, the mortality is excessive for the groups receiving ECT or neither treatment. There are no significant differences between SMRs among the four treatment groups, as demonstrated by overlapping confidence intervals.