Opportunity-based suicide rates.

Abstract

Clarke (1984) discussed the possibility of basing crime rates on the number of opportunities for crimes being committed rather than per capita of the population. Crime rates can be expressed relative to the target of crime (for example, the number of burglaries per houselapartment), to the means of commission (for example, auto thefts per car), to routine activities on the part of the criminal (for example, how many houses does the burglar break into per houses encountered), or to situations in which crimes take place (for example, the rate of shoplifting per number of stores entered, both for the average shopper and for the shoplifter). Clarke's idea suggests the possibility that suicide rates might be expressed in similar ways. For example, in 1967, the year before emission controls were introduced for cars, there were 72.9 million cars in the USA, 198.7 million people, and 2049 suicides using car exhaust. This gives a rate of 1.03 suicides per 100,000 people per year or 2.81 suicides per 100,000 cars per year. Using estimates of firearms in America (Moscicki & Boyd, 1983-1985) we can estimate the suicide rate using firearms in the USA in 1979 as 6.87 per 100,000 people per year or as 9.38 per 100,000 guns per year. And using estimates of the number of drug prescriptions for psychotherapeutics issued (Anon, 1985) we can estimate the number of suicides by psychotherapeutics in 1983 as 1.20 per 100,000 people per year or as 2.17 per 100,000 prescriptions per year. Suicide rates based upon opportunities may be psychologically more meaningful in the light of modern theories of suicide that stress the importance of opportunities for committing suicide as a major factor in determining the suicide rate (Clarke & Lester, 1987).