According to a study, patients with mental disorders have lower fertility rates than their siblings, reports Medical Xpress.
The study conducted by Robert A. Power, from King's College London, and colleagues mainly looked at the fertility rate of patients diagnosed with schizophrenia, autism, bipolar disorder, depression, anorexia nervosa, or substance abuse against their siblings who remain unaffected and the common people to evaluate the "level of selection on causal genetic variants," said the report in Medical Xpress.
The data used for the study was found from the Swedish Multi-Generation Register and the Swedish Hospital Discharge Register. The individuals' data included 2.3 million from 1950 to 1970 birth group. Among the group, it was found that the patients who were affected had significantly fewer children as their fertility rate ranged from 0.23 to 0.93, when compared with the other women with depression.
During the study, when compared the fertility rate with patients' siblings there was a significant difference in their fertility rate. Sisters of patients with schizophrenia and bipolar disorder were significantly increased in fertility. The infertility rate is higher among men than in women, according to the study analysis. It further showed that brothers of patients with schizophrenia and autism had significantly lower fertility rate. Commonly all siblings of the patients with depression and substance use showed an increased rate of fertility, according to Medical Xpress.
"Our results suggest that strong selection exists against schizophrenia, autism, and anorexia nervosa and that these variants may be maintained by new mutations or an as-yet unknown mechanism," the authors wrote, according to Medical Xpress. "Vulnerability to depression, and perhaps substance abuse, may be preserved by balancing selection, suggesting the involvement of common genetic variants in ways that depend on other genes and on environment."
The study is published online in the January issue of JAMA Psychiatry.
