Seasonal swings in violent suicide.

Investigators have long noted that, at least in some populations, suicide rates peak in spring and summer, dropping off during fall and winter. A new study indicates that this pattern stems mainly irom steep jumps in violent suicides that occur in April and May in adults younger than 65 and in August for those of older ages.

Previous evidence suggests that chemical messengers involved in psychological reactions to various types of stress - such as unemployment, depression, alcoholism, and loneliness - exhibit regular dips and rises during the year, asserts a research team led by psychiatrist Michael Maes of University Hospital of Cleveland. Disturbances in these seasonal shifts may influence violent suicide, they theorize.

Maes and his co-workers reviewed officially mandated physician reports of all deaths by suicide and homicide in Beigium between Jan. 1, 1979, and Dec. 31,1987. A total of 19,943 suicides and 1,462 homicides occurred in this nine-year period. A majority of those who killed themselves used violent means, such as guns, hanging, or jumping off a high place. The remainder used nonviolent methods, often a drug overdose or carbon monoxide inhalation.

The weekly number of violent suicides peaked in April and May for adults younger than 65 and in August for older adults. At all ages, both violent and nonviolent suicides occurred more oftenamongmenthanamon women.olderadultsdisplayeda greater tendency to kill themselves in violent ways.

No seasonal pattern emerged for homicides. This suggests that murder and violent suicide stem from different biological and psychological triggers, the researchers contend in the Septembet AMERICAN JOURNAL OF PSYCHIATRY.

The difficulty of obtaining handguns in Belgium may discourage some citizens from attempting violent suicide, they note (SN: 8/15/92, p.102). And physician reports probably underestimate the total number of suicides. Still, the seasonal swings in violent suicides appear genuine, the scientists argue.