Research: Increased risk of bipolar disorder for children of very young or very old parents

Children born to parents who are either very young or very old face an increased risk of developing bipolar disorder (formerly manic-depressive disorder) later in life, a new international scientific study shows. The risk is higher for children born to a mother or father under 20 years of age, and for those whose mother was over 35 or father over 45 at birth.

Researchers from four countries (Spain, Italy, the Netherlands, Australia), led by Dr Giovanna Fico of the University of Barcelona, who made the announcement at the European College of Neuropsychopharmacology conference in Vienna (15-18 October) and published in the journal European Neuropsychopharmacology, conducted a systematic review and meta-analysis of all published research on bipolar disorder in relation to age. In total, data on approximately 13.43 million individuals were analysed, of which 217,089 were diagnosed with bipolar disorder.

It was found that in general, older men (over 45 years old) are more likely (29%) to have a child with such a mental condition than fathers aged 25-29 years, while older mothers are 20% more likely to have a child with bipolar disorder than women aged 25-29 years. For very young parents up to 20 years of age, the risk of having a child with bipolar disorder is increased by 23% for mothers and 29% for fathers respectively.

«Parental age is a factor that affects many things, including fertility and some neuropsychiatric disorders. What we found is slightly unusual because both younger and older parents have an increased risk of having a child with bipolar disorder. The increased risk is moderate, but it's real. We can speculate that for younger parents environmental factors such as socio-economic problems, lack of support, stress or immunological factors play a role, while for older parents genetic factors may be involved, but the truth is that we don't really know,» said Dr Fico.

Bipolar disorder is characterised by intense mood swings, from great euphoria to depression. It is quite common and affects, to a greater or lesser extent, about 2% of the population. The disease, among other things, increases the risk of suicide and premature death from other causes. It is considered highly hereditary and if one parent has bipolar disorder, then there is a 15% to 30% chance of passing it on to their children. Young people with the disease, when in a manic phase, have more risky behaviour in sexual matters and more.