The first phase following the diagnosis of a first psychotic episode (FEP), is crucial to determine clinical and functional long-term outcome. Cannabis exerts a mediating action on the debut of the disease and determines a poor prognosis.

The description of a specific population profile of increased vulnerability to maintain cannabis use after a FEP could help to identify this high risk subtype of patients and speed up the implementation of specific interventions.

One hundred and seventy-eight patients were recruited from PAFIP (early intervention program on FEP), obtaining detailed socio-demographic assessment. They were followed-up for a year during which cannabis consumption was assessed by Drake scale every three months. We divided the sample into two groups:

– those patients who neither smoked cannabis before the FEP nor during follow-up period (nn);

– consumers group: cannabis users before the FEP who kept on smoking during the follow-up period (ss) and those who smoked before the FEP and gave up consumption during follow-up (sn).

Statistically significant differences between groups were observed. The consumers group (ss + sn) had an earlier age of onset, most were male, unemployed, single, prone to loneliness and they were concomitant users of alcohol and tobacco.

The use of cannabis has a detrimental effect on the outcome of schizophrenia. A specific and early intervention could contribute to prognostic improvements. Identifying cannabis consumption subtypes could be useful for this purpose.

The authors have not supplied their declaration of competing interest.