Although some studies have suggested inverse relationships between psychopathy and intelligence , including with regards to verbal IQ , Hare and Neumann state that a large literature demonstrates at most only a weak association between psychopathy and IQ , noting that the early pioneer Cleckley included good intelligence in his checklist due to selection bias ( since many of his patients were `` well educated and from middle-class or upper-class backgrounds '' ) and that `` there is no obvious theoretical reason why the disorder described by Cleckley or other clinicians should be related to intelligence ; some psychopaths are bright , others less so '' .
Some studies suggest a connection between psychopathy and IQ. ,