Children of older fathers more likely to have bipolar disorder

Older age among fathers may be associated with an increased risk for bipolar disorder in their offspring, according to a report in the September issue of Archives of General Psychiatry.

Bipolar disorder is a common, severe mood disorder involving episodes of mania and depression, according to background information in the article. Other than a family history of psychotic disorders, few risk factors for the condition have been identified. Older paternal age has previously been associated with a higher risk of complex neurodevelopmental disorders, including schizophrenia and autism.

Emma M. Frans, M.Med.Sc., of the Karolinska Institutet, Stockholm, Sweden, and colleagues identified 13,428 patients in Swedish registers with a diagnosis of bipolar disorder. For each one, they randomly selected from the registers five controls who were the same sex and born the same year but did not have bipolar disorder.

When comparing the two groups, the older an individual's father, the more likely he or she was to have bipolar disorder. After adjusting for the age of the mother, participants with fathers older than 29 years had an increased risk. "After controlling for parity [number of children], maternal age, socioeconomic status and family history of psychotic disorders, the offspring of men 55 years and older were 1.37 times more likely to be diagnosed as having bipolar disorder than the offspring of men aged 20 to 24 years," the authors write.

The offspring of older mothers also had an increased risk, but it was less pronounced than the paternal effect, the authors note. For early-onset bipolar disorder (diagnosed before age 20), the effect of the father's age was much stronger and there was no association with the mother's age.

"Personality of older fathers has been suggested to explain the association between mental disorders and advancing paternal age," the authors write. "However, the mental disorders associated with increasing paternal age are under considerable genetic influence." Therefore, there may be a genetic link between advancing age of the father and bipolar and other disorders in offspring.

"As men age, successive germ cell replications occur, and de novo [new, not passed from parent to offspring] mutations accumulate monotonously as a result of DNA copy errors," the authors continue. "Women are born with their full supply of eggs that have gone through only 23 replications, a number that does not change as they age. Therefore, DNA copy errors should not increase in number with maternal age. Consistent with this notion, we found smaller effects of increased maternal age on the risk of bipolar disorder in the offspring."

Source: JAMA and Archives Journals

Related stories:

Psychiatric disorders common among college-age individuals; few seek treatment
Psychiatric disorders appear to be common among 18- to 24-year-olds, with overall rates similar among those attending or not attending college, according to a report in the December issue of Archives of General Psychiatry. Almost half of college-aged individuals meet criteria for substance abuse, personality disorders or another mental health condition during a one-year period, but only one-fourth of those seek treatment.
Risky decision-making essential to entrepreneurialism
Whether someone will become the next Richard Branson, Steve Jobs or Henry Ford may be down to whether they make risky decisions, scientists at the University of Cambridge have concluded.
Study provides insight on a common heart rhythm disorder
University of Iowa researchers and colleagues in France have identified a gene variant that causes a potentially fatal human heart rhythm disorder called sinus node disease. Also known as "sick sinus syndrome," the disease affects approximately one in 600 heart patients older than 65 and is responsible for 50 percent or more of the permanent pacemaker placements in the United States.
Family therapy helps relieve depression symptoms in bipolar teens
Family-focused therapy, when combined with medication, appears effective in stabilizing symptoms of depression among teens with bipolar disorder, according to a report in the September issue of Archives of General Psychiatry.
Sex differences seen in response to common antidepressant
Women with depression may be much more likely than men to get relief from a commonly used, inexpensive antidepressant drug, a new national study finds. But many members of both sexes may find that it helps ease their depression symptoms.
Scientists learn how food affects the brain
In addition to helping protect us from heart disease and cancer, a balanced diet and regular exercise can also protect the brain and ward off mental disorders.
Protein on 'speed' linked to ADHD
A genetic change in the dopamine transporter – one of the brain's dopamine-handling proteins – makes it behave as if amphetamine is present and "run backward," Vanderbilt University Medical Center investigators report this week in The Journal of Neuroscience.
Report confirms increased risk of smoking, substance abuse in bipolar adolescents
A study from the Massachusetts General Hospital (MGH) supports previous reports that adolescents with bipolar disorder are at increased risk for smoking and substance abuse. The article appearing in the June Drug and Alcohol Dependence – describing the largest such investigation to date and the first to include a control group – also indicates that bipolar-associated risk is independent of the risk conferred by other disorders affecting study participants.

News discussion:

Medicine & Health news