There is a recent article in The Telegraph linking high childhood IQ to bipolar disorder in young adulthood. The finding is based on a massive study of 1,881 people, and replicates an earlier study showing that among 700,000 Swedish teenagers, those with high grades had nearly four times the risk of adult bipolar disorder as those with average grades, and their increased risk persisted even when controlling for the education and socioeconomic background of their parents. The link was highest for subjects emphasizing verbal and musical abilities, and weaker for math and science.
Daniel Smith, who led the more recent study, is quoted as saying:
There is something about the genetics underlying the disorder that are advantageous.
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 new research may explain a lot. For example, if intelligence can be defined as the cognitive ability to adapt: to take whatever situation you’re in and turn it around to your advantage, I’ve always wondered how some ridiculously brilliant people can achieve so little wealth an power. But if high IQ folks are more likely to be burdened with a huge emotional problem like bipolar disorder to adapt to, their lack of conventional success is easier to understand.
It’s also evidence for something I would call organic giftedness. One has often heard the term organic retardation to describe people with Downs Syndrome and other genetic mutations that are not part of the normal polygenetic variation in IQ, and thus create a surplus of people with IQs below 50; far more than the normal curve (which is based on biologically normal people) would predict.
Organic retardates are contrasted with familial retardates who can have equally low IQ, but their low IQs are related to normal genetic variation, not any kind of disorder, and thus they physically and behaviorally blend into society; some are even called six hour retardates, because their problems are confined to do the abstract reasoning of school, but they can be perfectly functional when school lets out.
Perhaps a similar organic vs familial dichotomy might apply among the gifted. We might have the organic gifted, whose high IQ is caused by some harmful genetic mutation, and thus are afflicted with burdens like bipolar disorder, and the familial gifted, whose high IQ is just caused by biologically normal polygenetic variation.
This might also explain the popular idea that there is an optimum IQ, usually thought to be anywhere from 125-150, where those above IQ 150 are disproportionately likely to be failures. Indeed a member of Prometheus told me that up to half of all people he knew with IQs above 150 grew up to be what society would consider losers, working in very low status jobs or living off welfare, but those with IQs of 130-140 were almost always successful.
Of course I’ve never seen any scientific evidence to prove this theory, but very few studies have the sample size, or the incredibly high ceiling tests, to meaningfully study folks with adult IQs above 150. The Promethean felt not even the older much harder SAT, which has a ceiling of IQ 170, was actually measuring IQ above 140 because the questions weren’t hard enough.
Most people who believe in the optimum IQ theory (and I’m extremely skeptical of non-linear IQ theories), explain it in terms of high IQ causing social isolation and values and priorities that conflict with what society defines as success. However a more interesting possibility is that IQs above 150 are so rare on the normal curve, that many people who are that brilliant are actually genetic mutants, and it’s the side-effect of their genetic mutations (i.e. bipolar disorder and who knows what else) that is causing their problems, and not the high IQ itself.
The mutation theory would also explain the fact that far more people score above IQ 150 than the normal curve would predict, especially on the older chronological age ratio IQs that were not forced to fit a bell curve the way modern deviation IQs largely are.
On the other hand, I know of no physical abnormality linked to high IQ the way unique physical characteristics in Down syndrome and Williams syndrome are linked to low IQ. I know of no chromosomal abnormalities linked to high IQ the was trisomy 21, Fragile X syndrome, and Turner syndrome are linked to cognitive impairments. As commenter Swank is always saying, intelligence is extremely complex, so genetic mutations are more likely to harm it than improve it.
However while massive genetic abnormalities like having an extra chromosome seem to dramatically lower IQ and create a very different physical appearance, it seems there might be many weaker mutations, that enhance IQ to some degree, and do damage to sensitive traits like personality, yet leave the body and face largely unscathed. Indeed we’ve had people on this blog who claim to have incredibly high test scores, yet don’t seem all that mentally stable. 🙂