Cannabis use prior to first onset psychosis predicts spared neurocognition at 10-year follow-up

Schizophr Res. 2005 Jun 1;75(1):135-7. doi: 10.1016/j.schres.2004.10.006.


A priori cannabis use was recorded at index admission for 112 participants in the Manchester first-episode psychosis cohort. 69 of the 100 surviving (mainly schizophrenia) patients were followed up 10-12 years later and assessed on a battery of clinical, behavioural and neurocognitive measures. Individuals who had not used cannabis before the first episode of illness were generally indistinguishable from cannabis users at follow-up, except that the latter group evidenced a marked 'sparing' of neurocognitive functions. These findings are briefly discussed in relation to other casual factors in psychosis.

MeSH terms

  • Case-Control Studies
  • Cognition*
  • Comorbidity
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Marijuana Abuse / epidemiology*
  • Schizophrenia / epidemiology*
  • Schizophrenic Psychology*