Children born to couples married for less than 3 years have an increased risk for schizophrenia, regardless of parental psychiatric disorders and paternal age, according to research results published in Schizophrenia Research.
Previous research has shown an association between short duration of marriage (DoM) and increased offspring risk for schizophrenia and considered preeclampsia to be the explanation. Researchers re-examined the associations between DoM and schizophrenia, accounting for parental psychiatric disorders, parental ages, and fathers’ age at marriage.
Continuous and stratified Cox proportional hazards models estimated relative risk (RR) for schizophrenia in 90,079 offspring from the prospective population-based Jerusalem Perinatal Cohort Schizophrenia Study. Using cross-linkage to Israel’s psychiatric case registry, researchers identified schizophrenia diagnoses in offspring and parental diagnoses of schizophrenia or other psychiatric conditions birth certificate records that provided DoM and paternal age at marriage data.
The RR for schizophrenia decreased for each 5 years of DoM in the full model. Compared with the offspring of parents married for ≥10 years, offspring born to shorter-married couples had the highest RR: <2 years: 1.53 (1.11-1.66); 2-4 years: 1.38 (1.05-1.81); and 5–7 years: 1.11 (0.87-1.42) Researchers eliminated apparent risk related to fathers’ age at marriage after accounting for DoM and paternal age.
The study defined minimal periods of a couple’s sexual cohabitation as the duration of their marriage. “The risk from a short period of parental sexual cohabitation may be a modifiable risk factor for offspring schizophrenia risk. The results highlight a novel significant risk factor for fathers related to their duration of sexual contact with the mother prior to conception, which is associated with preeclampsia, proposed to be the linking mechanism. This common condition could underlie the immune activation that is proposed to underlie a central pathology for the disease,” the researchers concluded.
Malaspina D, Kranz T, Kleinhaus K, et al. Short duration of marriage at conception as an independent risk factor for schizophrenia [published on March 8, 2019]. Schizophr Res. doi: 10.1016/j.schres.2019.03.001