Cannabis use is associated with schizotypy and attentional disinhibition

While most neurochemical research into the pathogenesis of schizophrenia (SZ) has focused on the dopaminergic, glutamatergic, and serotonergic systems, the exact nature and cause of this disorder have proven intractable. Given the recent discovery and elucidation of the endogenous cannabinioid system, a re-examination of the cannabis-induced exacerbation hypothesis of SZ is warranted. The purpose of the present study was to assess whether current cannabis users exhibit personality correlates and neurocognitive deficits similar to those observed in SZ patients. 15 current cannabis users, 15 drug-free controls, and 10 past cannabis users were assessed on tasks which assess attentional inhibition, spatial working memory, olfactory identification, and schizotypal personality. Current cannabis users demonstrated deficits in attentional inhibition, decreased reaction time, and significantly higher scores on the schizotypal personality questionnaire (SPQ) compared with the non-using and past cannabis using groups. No group differences were found on the working memory or olfactory identification tasks. These results suggest that cannabis use can mimic attentional deficits seen in acute schizophrenia and is associated with schizotypal personality, thus setting the stage for a possible cannabinoid model of SZ.