Investigation of factors associated with the achievement of cannabis abstinence amongst a first episode population with a history of problematic cannabis use

Background: Cannabis use amongst those with first episode psychosis (FEP) is prevalent and associated with negative outcomes. However, a move to cannabis abstinence amongst problematic cannabis users from this group is not uncommon. The aim of this thesis was to improve understanding of the factors influencing achievement of cannabis abstinence in FEP assuming the findings would assist in the development of more effective treatments for persistent cannabis users. Methods: Three pieces of research were undertaken to meet the aims of the thesis including: (i) a systematic narrative synthesis of the cannabis abstinence literature; (ii) a qualitative study with a sample of former problematic cannabis users with FEP investigating participant’s views of factors that contributed to their cannabis abstinence and their recommendations for treatment for persistent users and; (iii) a quantitative study of the influence of cannabis using contacts and conflict in social networks on cannabis abstinence. Results: Methodological weaknesses challenged efforts to develop a cohesive synthesis of existing cannabis research. Within the research, health concern is the most frequently endorsed factor underpinning the shift to cannabis abstinence followed by maturational factors incorporating role transitions and changing experiences and expectations of cannabis use. Similar factors were highlighted in the qualitative interviews though fell into chronological order with the initial health crisis of a first episode of psychosis or another keystone life event inducing a re-appraisal of future cannabis use. Thereafter, internal and external factors including aversive treatment experiences and social networks seemingly facilitate the successful achievement and maintenance of cannabis abstinence. Discussion: Opportunities to secure abstinence amongst problematic cannabis users are evident amidst the crisis of a first episode of psychosis. Timely intervention early in the course of psychotic illness with a broad, recovery orientated focus that includes input to social networks may improve the likelihood of sustained abstinence.