Paternal age older than 25 years and maternal age older than 22 years were shown to be associated with schizophrenia in offspring, and higher paternal age was shown to be associated with other mental disorders, according to the results of recent research published in the International Journal of Psychiatry in Clinical Practice.
In this case-control study, 231 participants with schizophrenia, 56 participants with other severe mental disorders, and 204 healthy control participants were enrolled from Greece. The paternal and maternal ages of the participants were compared between cases and controls. Paternal age groups were assessed in 5-year intervals with cutoffs of 20, 25, 30, 35, and 40 years. Maternal age group cutoffs were 20, 22, 26 (mean maternal age for Greek population 30-50 years ago), and 35 years.
Compared with healthy control participants, participants with schizophrenia had higher paternal age (32.55 vs 29.42 years; P <.001) and maternal age (27.66 vs 25.46 years; P <.001). When parental ages were compared between participants with schizophrenia and participants with other severe mental disorders, no difference was reported (P >.05).
Patients with schizophrenia had almost 3-fold increased odds of having paternal age older than 25 years (odds ratio [OR], 2.96). Similarly, other mental disorders were associated with increased odds of paternal age older than 25 years (OR, 2.85).
Patients with schizophrenia had higher odds of both paternal age older than 25 years and maternal age older than 22 years (OR, 1.88), as well as paternal age older than 30 years and maternal age older than 26 years (OR, 2.23).
The study authors concluded that the study results support “the suggestion that advanced paternal age constitutes a risk factor (in a non-dose-dependent and gender-independent way) for the development of schizophrenia but also for other mental disorders. In contrast, advanced maternal age characterises schizophrenia specifically.”
Fountoulakis KN, Gonda X, Siamouli M, Panagiotidis P, Moutou K, Nimatoudis I, et al. Paternal and maternal age as risk factors for schizophrenia: a case-control study [published online October 25. 2017]. Int J Psychiatry Clin Pract. doi: 10.1080/13651501.2017.1391292