Apparent higher brain weight in suicide victims: possible reasons

In 2000 we tested previously reported findings by Salib and Tadros that brain weight of fatal self-harm victims is higher than of those who died of natural causes. Our results were based on data from 15 suicides and 15 deaths of other causes. Data included matching variables of age, sex, time between death and postmortem examination, and temperature of the surrounding environment. The exploratory variables were brain weight and method of death. No significant difference was found between the brain weights of suicides and others. On the other hand, some differences were obtained for different suicide methods, which also differed in the temperature of the environment, this being lower for the group of suicides that occurred outdoors (around or below 0 degrees C). Once we excluded all the outdoor cases and controls, a significantly higher brain weight was obtained for suicide cases. These and previous results are intriguing and require explanation. Respirator brain syndrome as described by Moseley, Molinari, and Walker in 1976 may provide only a partial explanation. Another possible suggestion is that higher brain weight in suicide victims may be related to previously demonstrated increased amygdala blood flow and subsequent amygdala enlargement due to the increased processing of emotional information.