Whilst intake of THC has been associated with transient cognitive deficits, mixed results for the intake of stimulants have been reported with both better and worse cognitive performance in non-affective psychosis. It is likely that the effect of both cannabis and stimulants use on cognition in patients with non-affective psychosis is timerelated. Possibly,current illicit drug use, like cannabis, influence cognition more negatively, while previous drug use is a marker of a different pathway to psychosis