The association between cannabis and psychosis makes crucial the intervention on cannabis use disorder at first episodes of psychosis (FEP), especially among young population. In this group of patients, the harmful potential of cannabis is more evident by its influence on neurodevelopment. However, the nature of the association cannabis-psychosis is not clearly described. It seems to represent a mediating factor for an increased risk of psychosis in healthy and high-risk populations, determining an earlier age of onset and worsening long term outcome.

To assess the impact of cannabis in terms of functional and clinical prognosis in patients recruited after a FEP.

PAFIP is an early intervention program for early stages of psychosis. One hundred and sixty-three were included, followed-up at regular intervals of six months for three years with administration of clinical and functional scales (BPRS, SAPS, SANS, CDRS, GAF and Drake). Patients were divided into three groups: (1) those non-users neither before the onset nor during follow-up (nn) PEP, (2) consumers before the FEP and during follow-up (ss) and (3) consumers before the FEP that gave up consumption during follow-up (sn).

No statistically significant differences were observed in terms of functionality at three-year follow-up endpoint but a trend to a better-preserved functionality in the sn group. The sn group presented lower scores in scales for positive symptoms with respect to the comparison groups.

The interruption in cannabis use may have a beneficial effect on short-term clinical prognosis and functionality on long term.

The authors have not supplied their declaration of competing interest.