Bipolar risk rises with father's age

Bipolar risk rises with father's age

Adam Cresswell, Health editor September 02, 2008
CHILDREN of older fathers are more likely to have bipolar disorder - a discovery that could explain the increasing numbers of people diagnosed with the condition.
Compared with the offspring of fathers aged 20 to 24, people whose fathers were aged 55 or over at the time of their birth are 37 per cent more likely to be diagnosed with bipolar disorder.
Children of fathers aged 30-34 had an 11 per cent increased risk of bipolar, while children of fathers aged 40-44 had a 15 per cent increased risk.
Having an older mother also increased the risk, but the effect was far less pronounced.
The research is based on nearly 13,500 Swedish people with bipolar disorder, a severe mood disorder that causes repeated peaks of euphoria and hyperactivity followed by troughs of depression.
The authors of the study, published in the US journal Archives of General Psychiatry, said paternal age was already known to be linked to other developmental disorders such as schizophrenia and autism. They suggested the findings might reflect the increased risk of DNA mutations in sperm cells, which, unlike a woman's eggs, undergo hundreds of replication cycles in which errors can occur.
Australian psychiatrist Gordon Parker, executive director of the Black Dog Institute, said the findings were important, and might explain why diagnoses of bipolar disorder had been rising.
In 1992, according to the Australian Bureau of Statistics, 35 per cent of fathers of children aged 0-14 were under 35. This fell to 26 per cent by 2003. The proportion of fathers aged 45 and over rose from 19 per cent in 1992 to 25 per cent in 2003.
However, Professor Parker said as the existing risk of bipolar disorder was thought to be between 4 and 6 per cent, the effect of the increases remained slight.
"I would hate to see any concern in the community that people shouldn't have babies because they have bipolar disorder in their family," he said.
"If you have bipolar disorder in your family, you are more likely to end up in Who's Who, because high intelligence and creativity is over-represented in families with bipolar disorder."