Dyslexia among Swedish prison inmates in relation to neuropsychology and personality.

Several investigations have reported high frequencies of reading and writing disabilities in criminal populations. The aims of the present study were to assess the frequency of dyslexia among Swedish prison inmates and to relate dyslexia to other indices of neuropsychological functions. Sixty-three prison inmates with Swedish as their native language, age 19 to 57 years, were examined by interviews, tests of academic achievement, and neuropsychological assessment. Twenty-six (41%) were diagnosed as dyslexic. As expected, the dyslexic group performed more poorly on verbal tests as compared to the normal readers among the prison inmates, but they also performed more poorly on tests measuring nonverbal abilities. The dyslexic group had higher frequencies of paranoid and avoidant personality disorders compared to the nondyslexics. They also reported higher levels of anxiety and suspicion and a lower degree of socialization. Previous studies report low IQ to be associated with criminal propensity, supporting the interpretation that a double handicap (dyslexia and low IQ) increases the risk of entering a criminal career and remaining in it.