Patterns of cannabis use in first-episode psychosis

There is ample evidence that patients with psychosis are more likely to<br/>use illicit substances than the general population, with cannabis being the most<br/>popular. Research has also shown that cannabis use is associated with poor<br/>prognostic outcomes in patients with an established psychotic disorder. It is<br/>important to understand the reasons patients with psychosis endorse for their<br/>cannabis use and findings so far point towards an ‘alleviation of dysphoria’ model<br/>rather than the ‘self-medication’ hypothesis. It is not known how the level of<br/>motivation to change cannabis use can affect patients’ actual use. Lack of<br/>validated readiness to change questionnaires for use with psychotic populations<br/>makes it essential to develop and validate such measures.<br/>The aim of this thesis was to evaluate the reasons for cannabis use and its<br/>effects on psychotic outcomes in a patient cohort with first-episode psychosis.<br/>The association between cannabis use and other illicit drug use was also<br/>investigated. Readiness to change was evaluated as a predictor of cannabis use<br/>outcomes using two questionnaires.<br/>The main finding was that cannabis use was not associated with psychotic<br/>outcomes but was related to other illicit drug use. With regards to reasons,<br/>patients chose enhancement and social motives as most important for their<br/>cannabis use providing support for the ‘alleviation of dysphoria’ model.<br/>Preliminary analysis showed no clear pattern of association between readiness to<br/>change and cannabis use outcome. Utility of two readiness to change measures<br/>for use with patients with psychosis was not validated.<br/>These findings add to the small evidence base that cannabis use is not<br/>associated with prognostic outcomes in psychosis. No evidence for the self medication hypothesis was observed. Readiness to change was not associated<br/>with cannabis use outcomes signifying the need for using validated measures to<br/>assess motivation in psychotic populations.

Name dc:type.qualificationname

Doctor of Philosophy

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

King's College London

Year dc:date.issued

2013

Author dc:creator

• Kolliakou, Anna

Advisor dc:contributor.advisor

• Ismail, Khalida

Language dc:language

eng

Identifier

oai:kclpure.kcl.ac.uk:studenttheses/9d70beb1-9b58-4143-9bc6-87065b64866b

OAI identifier oai:identifier

oai:kclpure.kcl.ac.uk:studenttheses/9d70beb1-9b58-4143-9bc6-87065b64866b