Is there an increase of reproductive rates in schizophrenics? I. Critical review of the literature.

It is well-known that the fertility of schizophrenic patients, particularly males, is below the population average. The main measures of fertility (reproductivity) are marriage rate, marital fertility, and rate of reproduction. A review of the literature reveals the rate of reproduction of schizophrenic patients to be 30% to 80% of the general population, the reduction being mainly due to reduced probability of marriage. At least one investigation presented evidence for an increase in marriage rate and rate of reproduction in schizophrenic patients relative to the general population in recent time. If this increase were to be confirmed it would undoubtedly have practical as well as theoretical implications. The hypothesis of a compensatory higher fertility of healthy relatives of schizophrenics based on a physiological advantage is empirically unproven. Additionally, the concept of a balanced polymorphism in schizophrenia rests on a superficial analogy with Mendelian traits.