Scientists at the universities of Glasgow, Bristol, Cardiff and Texas looked at data on more than 1,800 participants in Children of the 90s and found that higher childhood IQ could indicate greater risk of bipolar disorder in adulthood.
The researchers examined the data to see if there was an association between participants’ IQ at age eight and lifetime manic features, which were assessed when they were aged 22-23. The children’s verbal IQ (VIQ) and performance IQ (PIQ) were combined to give a full-scale IQ (FIQ) measurement.
The final results – based on 1,881 individuals – showed that those who scored in the top 10 per cent of manic features had a mean childhood IQ almost 10 points higher than those scoring in the lowest 10 per cent of manic features. The association appeared to be strongest for verbal IQ (VIQ).
Professor Daniel Smith, in the Institute of Health & Wellbeing, University of Glasgow, said:
A possible link between bipolar disorder and intelligence and creativity has been discussed for many years and several 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.
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.
Suzanne Hudson, Chief Executive of Bipolar UK, added:
Given the rise in requests for support from parents and families of children to Bipolar UK, research that helps identify young people more at risk of developing bipolar disorder is vitally important.