A sex difference in the seasonal variation of suicide rate: a single cycle for men, two cycles for women.

The marked seasonal fluctuation in suicide rates observed by Durkheim appears to be diminishing, and in some cases, to have vanished. In this study, suicide data in Britain from 1958 to 1974 were studied by auto-correlational methods. A cyclical variation was found for both men and women. Men showed a single twelve monthly cycle whereas women showed two cycles. No explanation for this difference is immediately apparent.