A time series analysis of suicide in Northen Ireland and the USA for 1960 to 1984 revealed different correlates. Whereas divorce rates predicted national suicide rates in the USA, birth and marriage rates predicted suicide rates in Northern Ireland.
The major sociological theory proposed for understanding variations in national suicide rates was that of Durkheim. Durkheim proposed that two broad social characteristics were in large part responsible for the appearance of suicidal behaviour: social integration, the degree to which the people in a society were interconnected through social relationships, and social regulation, the degree to which the emotions and desires of people in the society were controlled and channeled by the social norms and customs.
Durkheim argued that suicide would be common when social integration was very strong (altruistic suicide) or very weak (egoistic suicide) and when social regulation was very strong (fatalistic suicide) or very weak (anomic suicide). Later theorists have argued that Durkheim placed more emphasis than was warranted on very strong social integration and regulation. Johnson argued, for example, that suicide would be more common when social integration and regulation were weak.