Significantly Elevated Suicide Risk

Mortality studies of psychiatric populations have demonstrated excess mortality for most diagnostic subgroups. Amongst the causes of premature death, suicides play a prominent role. Indeed, as many as 15% of unipolars, 10% of bipolars and 8% of schizophrenics commit suicide, in both inpatients and outpatients, and in virtually all countries around the world. These percentages vary by approximately ±5% across studies, but are remarkably stable over the past decades, thus suggesting that the broad administration of antidepressants and has not substantially influenced suicide rates in psychiatric populations. The extent to which prophylactic lithium treatment reduces the mortality of manic-depressive patients is still the object of investigation, although preliminary results are encouraging. Much emphasis has been laid by researchers on the identification of factors predicting suicide risk in psychiatric patients, as well as on the development of potent therapeutic interventions. Despite intensive efforts, however, effective prediction and intervention strategies have remained elusive. In particular, the lack of robust associations between death rates and any of the patients' characteristics investigated to date suggests that completed suicide might represent an etiologic entity which is largely independent of psychiatric diagnoses. Consequently, the overlap observed, for example, between suicide and affective disorders should be interpreted in terms of "comorbidity", rather than in terms of causal relationships.

Constant Over a Life Time

The results of our investigation into the distribution of suicide risk as a function of age clearly speak in favor of this hypothesis:
⇒ We found the risk of committing suicide to be constant over a lifetime and virtually the same for depressive, schizoaffective, schizophrenic and, with certain restrictions, for borderline patients as well.

Biological Predisposition?

The respective factor showing up across studies could be related to common biological features such as deficiencies in certain transmitter systems. Clearly elevated aggression scores in the premorbid personality of persons who later committed suicide point in the same direction. Our finding that suicide groups show a linear risk function over age points to a serious methodological problem: Since standard approaches to measuring efficacy of anti-suicidal interventions are based on a comparison with the general population, the nonlinearity of the respective risk function with several distinct maxima can be expected to bias results, particularly, if the risk periods under comparison are short. We think that the methodological framework underlying research in this field deserves improvement.