Does cannabis really influence first episode psychosis outcome negatively?

Listen to the Author discussing their work: 

"Objectives: Different studies have concluded that cannabis use disorders (CUD) influenced negatively outcomes in first-episode psychosis (FEP). However, it is rarely mentioned if those cannabis users were also misusing other substances.. Our study examined the specific impact of different SUDs (alcohol, cannabis, psychostimulants) on symptoms, social functioning and service utilization of youth with FEP.
Methods: a prospective longitudinal of 2 years follow-up of 176 FEP between 18 to 30 years old, admitted to early psychosis programs in Montreal.
Results: Half of CUD present polysubstance use disorder. All substances (drugs and alcohol) are associated with lower functioning (GAF) but drugs have a greater negative impact on most measures at 2-year. Psychostimulants and poly-SUD are associated with bad symptomatic and functional outcome early in the course of illness (from the 1st year of treatment), persisting over time and higher service utilization (hospitalization). Persistent CUD is the only group that deteriorates from Year 1 to Year 2 (symptoms and functioning). However, psychostimulants abusers have a bad outcome from the first year.
Conclusions: The negative impact that has been attributed to CUD in previous studies could partly be attributed to methodological flaws (including polysubstance abusers in the cannabis users group). However, our study confirms CUD negative impact on outcome in youth with FEP. Attention should be given to cannabis misusers since their condition seems to worsen over time and to psychostimulant misusers since they have poorer outcome early during follow-up and a high utilization of hospitalization and emergency services."

Poster First Author: 
Clairélaine Ouellet-Plamondon
Conference Presented At: 
IAYMH 2015
Poster Date: 
October, 2015
Subject Area Tag: