Having a low IQ in early adulthood is linked to a higher risk of suicide - at least in men. Researchers from the Wellcome Trust studied 1.1 million men in Sweden who all took IQ tests when they did their national service. Over the next 24 years at least 18,000 of them had had to go to hospital at least once after trying to kill themselves. Even after allowing for age and socioeconomic status men with lower IQ scores were increasingly likely to have attempted suicide at least once, with the most common method being poisoning. The researchers can only speculate on the reasons for this link but two theories are that people with higher IQs have a greater capacity for problem solving and that they find it easier to talk about their problems with other people.
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