A high Intelligence Quotient (IQ) might protect people with a predisposition to developing schizophrenia from acquiring the disorder, a new study shows.

The study, led by the Virginia Commonwealth University and Lund University in Sweden, also says that siblings with a lower IQ have a higher risk of developing schizophrenia.

The research contradicts the popular notion that links schizophrenia to brilliance. Not having the IQ that is predicted based on a person's genes, family background and environmental factors such as upbringing makes a person more likely to acquire schizophrenia, if he or she has a tendency for it in the first place.

People with schizophrenia vary widely in their IQs, and intelligence is just one component of the risk factors associated with schizophrenia, the researchers said. The IQs of more than 1.2 million Swedish males born between 1951 and 1975 were assessed, and schizophrenia-related hospitalisations were tracked for 24 years until 2010.

Environmental factors can also reduce IQ, or intelligence, in people. These factors include childhood trauma, early drug use, poor environmental factors etc. Having a high IQ, meanwhile, does not completely reduce the risk of schizophrenia either. In fact there are well known cases of brilliant people who suffer from the illness, including the case of John Nash, the famous mathematician and thinker on whose life the film A Beautiful Mind has been made.

Until now, schizophrenia has, in fact, been associated with brilliance more than dullness of mind. The study shows that there seems to be no reason to suggest that extremely brilliant people have a propensity to suffer from the disease. Schizophrenia affects about one per cent of the world's population. It is a relatively rare mental disorder and is characterised by hallucinations, delusions, paranoia, cognitive impairment, social withdrawal, self-neglect and lack of motivation and initiative.

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