Mental Acuity - Gene Link Asserted...
Research on schizophrenia has taken an unexpected turn for researchers at the Feinstein Institute who found that a gene that plays a role in determining whether someone has this disease also seems to play a role in mental acuity and intelligence. (This in interesting note compared to APOEe4-risk for cognitive impairment in the case of Alzheimer's and Dementia)
The work, conducted at The Feinstein Institute's Zucker Hillside Hospital on Long Island, was originally aimed at studying the association between the gene dysbindin-1, located on chromosome 6, and an increased risk for developing schizophrenia, the debilitating mental illness whose sufferers are plagued by psychotic episodes and asocial behaviors.
"Our primary and first question wasn't to find genes for good cognition," said Anil Malhotra, principal investigator of the study. "It was to figure out what the effect of this risk form of the gene was, and that led us to our findings."
Malhotra and his team administered tests of mental acuity and took DNA samples from 213 schizophrenic patients and 126 healthy volunteers. The results showed that a specific variation of the dysbindin gene was not only associated with an increased risk for schizophrenia, but also with a low performance in general cognition. The researchers say this variation of the gene affects mental ability regardless of whether its carrier develops a mental illness, leading them to believe that the gene, in all its variations, is directly related to general intelligence.
"If having this risk form makes you perform worse, then in the other forms the converse is true—you perform better," Malhotra said.
The study is appearing in the journal Human Molecular Genetics, and found that the variant form of dysbindin-1 that is associated with lower intelligence was present in 7% of the general population and 12% of the schizophrenic population. In addition to an increased risk of schizophrenia, individuals who posses this gene variation can also expect to perform 3% to 5% percent worse on standardized neuropsychological cognition tests, which rate a person's mental skills in reading comprehension, attention, verbal fluency and memory.
According to Katherine Burdick, the study's principal author, these findings support the argument that genes (or the nature half of the nature vs. nurture equation) are significant determinants of intelligence.
Jensen has noted the link between intelligence and raw brainspeed.