Background. Gender differences are commonly reported in schizophrenia research, especially with regard to age at onset. Few studies have reported the age- and gender-specific incidence of schizophrenia in people aged up to 71 years, and no studies have reported the cumulative incidence of schizophrenia in people aged up to 71 years.

Method. Two cohorts were established by linking data from the Danish Civil Registration System (DCRS) with data from the Danish Psychiatric Central Register (DPCR), which covers all incident cases of schizophrenia from 15 to 71 years. We estimated the gender- and age-specific incidence rates of schizophrenia for people aged up to 71 years. We also estimated the cumulative incidences.

Results. The incidence rates for males significantly exceeded those for females in the age range from 17 to 40 years. By their 72nd birthday, 1·59% of males and 1·17% of females had developed schizophrenia.

Conclusion. Male sex is a major risk factor for the development of schizophrenia.