To evaluate the influence of cannabis in the long-term follow-up in patients with a first psychotic episode, comparing those who have never used cannabis with (a) those who used cannabis before the first psychotic episode but stopped it during the follow-up, and (b) those who used cannabis both before and after the first psychotic episode.

Patients were followed from the first psychotic admission. They were assessed at 1, 3 and 5 years obtaining information about functional outcome, positive and negative symptoms. At 8th year functional outcome was evaluated. Patients were classified in 3 groups: 40 that never used cannabis (NU), 27 that used cannabis and stopped during follow-up (CUS), and 25 that had continued use during follow-up (CU).

At baseline, there were differences neither in functional outcome nor in negative symptoms. The CUS group improved the functional outcome during the follow-up (p< 0.001), while CU and NU groups did not show any significant results (p= 0.466 and p= 0.370 respectively). CUS group had also a significant decreasing trend in negative symptoms (p= 0.012), whereas for the other two groups no significant results were observed (p= 0.069 and p= 0.226 respectively). All groups improved in positive symptoms during follow-up.

Although cannabis use has deleterious effect, to stop it after the first psychotic episode produces a clearly improvement in the long-term follow-up.