Author: Yangguang Ou
Institution: Florida State University
Date: September 2008
A recent Swedish study has shown that children with older fathers are more likely to contract bipolar disorder than those of younger fathers. This study brought the scientific community's attention to the connection between mental disorders and paternal age.
Bipolar disorder is a mental deficiency marked by severe mood swings between episodes of mania and depression. Before this study, no other risk factors had been associated with bipolar disorder other than family history.
The study compared the paternal age of approximately 13, 500 patients with bipolar disorder to those of approximately 67,000 people without the condition. According to Emma M. Frans and colleagues of the Karolinska Institute in Stockholm, Sweden, many factors were controlled during the study, including the number of children, maternal age, socioeconomic status, and family history of psychotic disorders. The results show that children born to fathers who are more than 55 years old are 1.37 times more likely to get bipolar disorders than those born to fathers in their twenties. Maternal ages were also examined during the study but proved to be insignificant compared to the statistics from the paternal studies.
"[The] personalities of older fathers has been suggested to explain the association between mental disorders and advancing paternal age. However, the mental disorders associated with increasing paternal age are under considerable genetic influence," wrote the authors of the research in the journal archives of General Psychiatry.
According to Frans and her colleagues, DNA copy errors can accumulate during the repetitive and continuous replication of the paternal germ cell line. Women, on the other hand, are born with their full supply of eggs and thus never replicate their genes more than 23 times, effectively decreasing the influence of maternal aging on genetic mutation frequencies.
Written by: Yangguang Ou
Edited by: Hoi See Tsao
Published by: Hoi See Tsao