Disorders of mood could be the price some people pay for high intelligence, research finds.
Psychologists have found that higher childhood IQ is linked to features of bipolar disorder in young adulthood.
The research adds fuel to the debate over the connection between intelligence, creativity and mental health issues.
For the research 1,881 people were followed from age 8 until they were 22 or 23-years-old.
Their IQ was measured along with any characteristics of mood disorders.
The results showed that having ten more IQ points at age 8 was linked to being in the top ten per cent for having manic personality traits in their early twenties.
Professor Daniel Smith, one of the study’s authors said:
“A possible link between bipolar disorder and intelligence and creativity has been discussed for many years and many studies have suggested a link.
In this large study, we found that better performance on IQ tests at age eight predicted bipolar features in young adulthood.
We are not saying that high childhood IQ is a clear-cut risk factor for bipolar disorder but rather that there is likely to be a shared biology between intelligence and bipolar disorder which needs to be understood more fully.
Many other factors – including family history of mental illness, childhood adversity, stressful life events and drug misuse – are known to increase an individual’s risk of developing bipolar disorder.
Our finding has implications for understanding of how liability to bipolar disorder may have been selected through generations.
One possibility is that serious disorders of mood such as bipolar disorder are the price that human beings have had to pay for more adaptive traits such as intelligence, creativity and verbal proficiency.
This work will inform future genetic studies at the interface of intelligence, creativity and bipolar disorder, and will help with efforts to improve approaches to the earlier detection of bipolar disorder in adolescents and young adults.”
The study was published in the British Journal of Psychiatry (Smith et al., 2015).