Variation in suicide and homicide by latitude and longitude.

Abstract

Lester (1973) reported that homicide rates were higher in the southern states of the USA than in the northern states, while suicide rates were slightly higher in the northern states than the southern states and much higher in the western states than in the eastern states. The present study sought to examine this relationship in various subgroups of the population. Using suicide and homicide rates for 1959-1961 as in earlier papers (Langberg, 1967; Massey, 1967) and the latitude and longitude of the capitals of each of the 48 continental states, the following results were obtained. The homicide rate varied with latitude for the total homicide rate ( r = 0.83, twotailed $ < 0.001), for the males' homicide rate (r = 0.84, p < 0.001), for the females' homicide rate ( r = 0.76, p < 0.001), and for the homicide rates of all age groups from 15 to 84 yr. There was no variation for age groups 0 to 14 yr. Homicide showed no variation with longitude, except that the homicide rate for those aged 75 to 84 yr. was higher in the west than in the east ( 7 = 0.30, p < 0.05). The suicide rate varied with longitude, being higher in the west than in the east for the total suicide rate ( r = 0.47, p < 0.01), for males ( r = 0.44, 9 <' 0.01), for females ( r = 0.43, p < 0.01), and for all age groups from 15 to 84 yr. (reaching statistical significance for all age groups except that for 65 to 74 yr.). The suicide rate was slightly higher in the northern states than in the southern states, but the correlation reached significance only for age groups 65 to 74 yr. ( r = 0.36, p < 0.02) and 75 to 84 yr. ( r = 0.30, p < 0.05). Thus, the variation with latitude and longitude in suicide and homicide rates appears to be a general phenomenon, except for the homicide rates of infants and children which show no such variation Explanations of these geographic variations will be explored in subsequent research.