IQ, Intelligence, and Mental Illness
There’s been some hypothesizing about the link between bipolar disorder and creativity, but how does IQ and intelligence correlate with mental disorders such as Schizophrenia and Bipolar disorder? The results are mixed, but interesting. Specifically, there is some disagreement between the IQ of an individual and the risk of developing bipolar disorder. However, the level of academic achievement, which might be a measure of creativity as well as intelligence, reveals a contrary position, supporting a possible premorbid link between bipolar disorder and general intelligence.
First, the bare facts. It’s been long thought that creativity is associated with bipolar disorder. The evidence is often anecdotal, but convincing to some degree. Great artists and mathematicians have long been thought to have the disorder, van Gogh, Pollock, Kurt Cobain, DMX, Graham Greene, Edgar Allen Poe, Virginia Woolf, and ground breaking mathematicians Georg Cantor and Emil Post. These artists are along with numerous actors and comedians and politicians (like Lincoln and Churchill). It seems that intelligence and creativity runs along side bipolar disorder.
But what about IQ, a very analytical test of intelligence. First, there must be some distinction between IQ tests. There are several methods of testing, but here I will focus on two: Raven’s Progressive Matrices (RPM) and National Adult Reading Test (NART). RPM is the test where they have the patterns of tic-tac-toe type images and then ask you which shape should complete the pattern. It is not an IQ test in the normal sense, it is a test of fluid intelligence. Fluid intelligence is the type of intelligence that determines how well one responds to new information without any background knowledge. This is opposed to the NART method, which allows for one’s previous knowledge to influence the results, that is, it allows crystalized intelligence to influence the results. Additionally, NART is not a full blown IQ test, rather it is a solid predictor of IQ. I wish I could have found a solid longitudinal test using something along the lines of the Stanford Binet test, but all the evidence that I could find used NART.
So the results of the NART testing found no correlation between premorbid IQ and developing bipolar disorder within 27 years of the test. However, they did find that lower IQs were associated with non-affective disorders like schizophrenia and psychosis.
However, it does not mean that IQ holds steady after the onset of bipolar disorder. In a PsychoMed article it’s found that there is even a discrepancy between bipolar I and II. In terms of IQ decline, it’s found that persistent depression leads to a higher risk of cognitive abnormalities. So perhaps mania is an offset to this decline.
Finally, there does seem to be a risk factor between general intelligence and the risk of bipolar disorder. In a study on Swedish students aged 16 who were A students, the study found that there was an increase in the likelihood of developing bipolar disorder. And the results were profound. There was a four fold increase in risk of developing bipolar disorder associated with achievement in school. Indicating that general intelligence, including both fluid intelligence and crystalized intelligence does have some correlation with developing bipolar disorder. Specifically, higher scores associated with music and language experienced higher risks. In addition to this, there was a 12 fold increase in the risk of developing bipolar disorder associated with high scores in arithmetic. Specifically, it is found that the risk of developing psychosis is associated with lower IQs as compared to higher IQs. This is a finding in keeping with the NART scores previously mentioned. The final finding of the meta analysis that psych central provided was that this indicates a different causal pathway between schizophrenia, bipolar disorder, and depression.
Posted on October 20, 2011, in Bipolar, Mental Health and tagged bipolar, bipolar disorder, depression, intelligence, IQ, mania, mental health, mental illness, schizophrenia. Bookmark the permalink. 6 Comments.