In this chapter we examine the effect on suicide rates of being deprived of family ties with spouse and children. It has been known at least since the work of Emile Durkheim that unmarried people have a higher suicide rate than married people. It is our objective in the present and subsequent chapters to identify and test the various implications of this effect.

In normal conditions, it has little impact on the total suicide rate because in most societies unmarried people are a small minority; consequently, their higher suicide rate has only a small impact on total suicide rates. To be more specific, let us consider a population A of 100,000 people for which the suicide rate is 15 per 105 and which comprises only married people (for the sake of simplicity we suppose that there are no children). In such a population there are nA = 15 suicides annually. How is this number modified in a population B similar to A in all respects except that it comprises 5% unmarried people? If we assume that the suicide rate of unmarried people is 15 X 2=30, the annual number of suicides will be nB =(15/105) X 0.95 X 105 + (30/105) X 0.05 X 105 =15.75, which represents a relative increase of (nB – nA)/nA = 5%. As might be expected (and will be seen in more detail subsequently) a change of this magnitude is likely to be hidden by the background noise of suicide rates.