Previous studies have linked increasing paternal age with schizophrenia and autism, but not bipolar disorder, formerly known as manic depression. Children born to fathers ages 30 to 34 were 11 percent more likely to be diagnosed as adults with the condition than those born to men 20 to 24. The diagnosis was 37 percent more likely in offspring of fathers 55 and older, the examination of Swedish health records found.
Lead researchers Emma M. Frans, a scientist at the Karolinska Institutet in Stockholm, identified 13,428 patients in Swedish registers with a diagnosis of bipolar disorder for the study.
After controlling for other factors like age of the individual's mother, number of siblings and family history of mental health problems, they found that older an individual's father, the more likely he or she was to have bipolar disorder. People with bipolar disorder can undergo swings in their mood between elation and depression. Patients may take excessive risks and even try to kill themselves.
The research, published in this month's Archives of General Psychiatry, suggests the risk may, in part, be explained by ageing sperm. There are chances of DNA errors when sperm cells replicate increases as men age, researchers said.
