Does psychosis affect motivation for use of cannabis? Jennifer L Seddon 1,2 , Alex Copello 1 & Max Birchwood 2 ,

1. Does psychosis affect motivation for use of cannabis? Jennifer L Seddon1,2, Alex Copello1 & Max Birchwood2, 1Addiction Research Group,2Psychosis Research Group; The University of Birmingham, UK. Discussion: In line with previous findings (Green, Kavanagh & Young, 2004, 2007) there was a significant difference in the patterns of cannabis consumption between those with and without psychosis, with cannabis used at much lower rates for those with co-existing FEP. Despite this there was no significant difference in the level of cannabis associated problems between the two groups. These findings are in line with the super sensitivity model and likely reflect the increased sensitivity and negative effects of cannabis for people with psychosis (Mueser, Drake & Wallach, 1998). The results suggest that the motives for use of cannabis are similar between cannabis users with and without co-existing psychosis. It is interesting to note that relief of psychotic symptoms was rarely endorsed as a reason for use of cannabis, suggesting that self medication may not account for the aetiology. Similarly there was no significant difference in cannabis expectancy between cannabis users with and without psychosis, although participants with FEP and no history of cannabis use expected significantly more negative effects of cannabis. This suggests it is the expectation of increased negative effects rather than diminished positive effects that inhibits use of cannabis for this group. Results: Participants: Cannabis users with FEP (N=11), cannabis users without FEP (N=13) , non-cannabis users with FEP (N=14). All participant groups were matched in terms of age and gender, and all participants were new clients entering treatment. • Background: • There is a high prevalence of cannabis use in first-episode psychosis, with cannabis associated with increased adverse outcomes for this population (Linszen et al, 1994; Caspari, 1999, Hides et al, 2006). Moreover the early stage of psychosis is regarded as a critical period which may influence the long term course of illness (Birchwood, McGorry & Jackson, 1997; Wyatt, 1991), therefore the use of cannabis in first episode psychosis (FEP) may have significant detrimental effects for long term outcome. The motivational mechanisms that drive use of cannabis for this population are therefore an important target for research. • Furthermore little is known about how motivation for cannabis compares between those with and without co-existing psychosis. It has been proposed that the use of substances in psychosis is driven by the need for self medication (Khantzian, 1997) or the alleviation of dysphoria (Mueser, Drake & Wallach, 1998). However very little research has directly compared the two populations and so the potential meditational effect of psychosis in the use of cannabis remains unclear. • Aim: • To compare the cannabis use behaviour of people with and without co-existing psychosis. • To examine if cannabis users with and without psychosis state different motivations for, and expectancy of, cannabis. There was a significant difference in the level of dependence [t(22)= -2.84; P<0.05] as well as the frequency [t(22)= 3.06; P<0.00], quantity [t(21)= -2.32; P<0.05] and amount spent on cannabis [t(22)= -4.21; P<0.000], with cannabis users with FEP using at significantly lower levels. Despite this there were no significant differences between the groups in the level of associated problems [t(22)= -.319; NS]. Fig 1: Cannabis use indices There was a significant difference in the reasons for use of cannabis, with enhancement, coping and social motives the most salient reasons accounting for use of cannabis for all participants. However there was no significant difference between the two groups in terms of motivation for cannabis. Conclusion: Results suggest that the motivational factors associated with use of cannabis are similar for cannabis users with and without co-existing psychosis, and psychosis related reasons do not appear to be salient motivators of cannabis use for people with FEP. Given the lack of differences in motivation for cannabis it is likely that the same interventions are suitable for use with both populations. However the question remains as to why there is increased prevalence of cannabis use in individuals with psychosis. • Method: • Participants- Participants were recruited upon entry to the early intervention service, Birmingham & Solihull NHS Foundation Trust and drug agencies from the West Midlands. Three participant groups were recruited; • cannabis users with FEP • people with FEP and no history of cannabis • cannabis users without FEP • Measures- All participants using cannabis completed the Severity of Dependence Scale (SDS; Gossop et al, 1995), the Kavanagh Drug Check (Kavanagh et al, 1998) and the drug motivation questionnaire (DMQ; Spencer, Castle & Michie, 2002). All three participant groups completed the marijuana effect expectancy questionnaire (MEEQ; Aarons et al, 2001). Fig 2: Motives for Cannabis There was a significant difference in cannabis expectancy with relaxation, craving & physical effects the most significant cannabis expectancies for all participants. 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Fig 3: Cannabis Use Expectancy Email: JLS860@bham.ac.uk Phone: +44 (0)121 414 7209 www.psychology.bham.ac.uk/research/groups/dsa/addiction.shtml Acknowledgements: Study funded by The University of Birmingham and Birmingham, Solihull Mental Health NHS Foundation Trust.