The degree to which an individual deviates in intelligence from their family is a more accurate predictor of schizophrenia development than the individual’s intelligence alone, according to a new study conducted by researchers at Virginia Commonwealth University and Lund University in Sweden.
The study confronts the conventional wisdom that low intelligence alone is a sufficient risk factor for schizophrenia development, going further to say that the risk for schizophrenia development is more accurately indexed by the degree to which an individual diverges from their family’s average intelligence level.
“Merely not doing well in school is not predictive,” said first author Kenneth S. Kendler, M.D., professor of psychiatry and human and molecular genetics in the Department of Psychiatry, VCU School of Medicine. “It is all in the deviation from the family expectation. If you have poor cognitive performance, but you come from a family where that is normal, then you do not have an increased risk of illness.”
Relatedly, someone could be a high academic achiever compared to the average student, but if they came from a family of intellectually superior people and were falling short of their family’s average intelligence then they would have a substantially increased risk for developing schizophrenia.