According to new research, children whose parents are particularly old or young are more likely to carry a risk of bipolar disorder.
Research that was presented at the ECNP Congress in Vienna has suggested that the risk of bipolar disorder is greater in children who were born to a mother or father younger than 20 years old, a mother older than 35, or a father older than 45 years old. The researchers have described this as a ‘U-Shaped Curve’ that shows an increased risk for older and younger parents.
The findings have been published in the journal European Neuropsychopharmacology.
What is Bipolar?
People who suffer from bipolar disorder quickly swing from moods of elation to moods of extreme depression. Bipolar is one of the most common mental illnesses and affects an estimated 2% of people. The condition carries a high risk of suicide and premature death. Bipolar is also known to have high heritability; if one parent has had bipolar, their child is 15%-30% more likely to suffer from the condition themselves.
“Parental age is a factor which affects many conditions, such as fertility and some neuropsychiatric disorders. What we have found is slightly unusual because both younger and older parents carry an increased risk of having a child with bipolar disorder. The increased risk is moderate, but real,” said study leader Dr Giovanna Fico, of the University of Barcelona.
“We can speculate that younger parents may be affected by environmental factors, such as socio-economic problems, lack of support, but also stress or immunological factors, and that older parents may have genetic factors coming into play, but the truth is we don’t really know”.
The research group was made up of academics from Spain, Italy, Australia, and the Netherlands. These researchers carried out a systematic review of studies from several countries which examined the relationship between bipolar and age.
The researchers observed that older men had 29% higher odds of having a child with bipolar disorder than men who had children between 25 and 29 years old. They also found that older women had 20% higher odds than mothers aged 25 to 29 years old.
The likely hood of younger parents having children with bipolar disorder also increased with a 23% higher chance for mothers under 20 and 29% for fathers under 20. All the analysis was corrected for biasing factors such as familial history for bipolar disorders and the age of the other parent.
Environmental factors are likely to contribute the risk of bipolar disorder
“Again, we must stress that this risk is moderate, and it must be kept in perspective. However, for those already at risk, age is another factor that should be taken into consideration, and so it may be that doctors need to counsel both younger and older couples if they have a risk of bipolar disorder. We also see this U-shaped curve in some other conditions, such as autism and some cardiovascular diseases,” explained Dr Fico.
The research team also outlined their intentions to produce further research on the risk of bipolar in children. The new research will focus on several environmental factors which might be related to the risk of bipolar disorder.
“We would like to explore how the exposure to pollution, climate changes, and urbanisation might affect the risk of some psychiatric disorders, and we want to try to understand if these factors help or worsen the course of the disorder,” concluded Dr Fico.