course of the disease, or to premature or inadequately managed return to work. doi:10.1016/j.schres.2007.12.152 86 – THE INTERACTION BETWEEN CANNABIS USE AND SOCIAL EXCLUSION IN FIRST EPISODE PSYCHOSIS M. Di Forti 1 , C. Morgan 1 , M. Russo 1 , V. Mondelli 1 , A. Butt 1 , J. Tse 1 , M. Aas 1 , R. Handely 1 , L. Gittens 1 , A. Seddigh 1 , C. Pariante 1 , P. Dazzan 1 , R. Murray 1 . 1 Institute of Psychiatry, Division of Psychological Medicine, United Kingdom Presenting Author details: m.diforti@iop.kcl.ac.uk De Crespigny Park, Sw19 1HN London, United Kingdom, Tel.: +44 207 8485352. Background: Cannabis use is associated with a risk of subsequently developing psychosis; individual susceptibility depends on age of onset of cannabis use and on genotype (Arseneault et al., 2004; Henquet et al., 2005; Caspi et al., 2005). Being unemployed, living alone, having no education and being single are also associated with increased risk of psychosis (Morgan et al., 2006). We predicted that cannabis use and these markers of social exclusion would interact to further increase the risk of psychosis. Methods: Case–Control Design: We collected socio-demographic, clinical and cannabis use (age at first use, frequency, length of use) information from a sample of 320 first-episode psychosis patients and 180 matched healthy volunteers. All the subjects were recruited as part of the Genetic and Psychosis (GAP) study which included patients who presented to the South London and Maudsley Trust. Results: There was no significant difference in the life-time prevalence of cannabis use or age at first use between cases and controls (p = 0.07). However, cases were more likely to be regular users (p = 0.05), to be current users (p = 0.04), to use high potency preparations of cannabis (p = 0.002) and to have smoked cannabis for longer (p = 0.01). We then compared social exclusion between 100 first episode cases and 100 controls. Cases were much more likely to report two or more markers of social exclusion than cases (OR = 13). Cannabis use and having two or more markers of social exclusion were statistically significantly associated with being a case (OR = 20). Conclusions: Cannabis use and being socially excluded interact in increasing risk of onset of psychosis. Acknowledgement: South London and Maudsley, NHS trust; Lambeth Early Onset Unit (LEO). doi:10.1016/j.schres.2007.12.153 87 – PREVALENCE OF SUBSTANCE USE IN FIRST-EPISODE PSYCHOSIS IN ENGLAND: FINDINGS FROM THE AESOP STUDY K. Donoghue 1 , J. Hart 2 , R. Mazzocini 3 , G. Doody 1 , C. Morgan 1 , R. Murray 1 . 1 Division of Psychiatry, University of Nottingham, Nottingham, England 2 Institute of Psychiatry, King College London, London, England 3 Department of Medicine and Public Health, University of Verona, Verona, Italy Presenting Author details: mcxkd3@nottingham.ac.uk Division of Psychiatry, Duncan Maclillan House, Porchester Road., NG3 6AA Nottingham, United Kingdom, Tel.: +44 7751217249. Background: Substance misuse in patients with first-episode psycho- sis is highly prevalent with epidemiological studies having indicated rates of up to 44%. However, considerable variance between countries has been reported and there has been little research into the correlates of substance misuse and psychosis in first-episode patients in England. Methods: All those (n = 568) aged 16–64 presenting to secondary services in defined catchments areas in South East London, Nottingham and Bristol were identified over a 2-year period (9 months in Bristol). Evidence for substance use in the year before the first- episode of psychosis was obtained from the PPHS, SCAN and clinical case notes for South East London and Nottingham. Results: A substance use rating was available for 469/511 of participants with evidence of substance use being present for 45%. Consistent with previous reports, more substance use was significantly associated with male gender and younger age. Logistic regression indicated that Black-African ethnicity was associated with a decrease in the likelihood of substance use compared to White-British (OR = 0.448, df =1, p = 0.010, 95% CI 0.243–0.827). A diagnosis of depressive-psychosis compared to a diagnosis of non-affective psychosis was also associated with decreased likelihood of substance use (OR = 0.367, df =1, p = 0.001, 95% CI 0.201–0.669). Conclusions: High rates of substance use in first-episode psychosis patients were further confirmed by this study. Those most at risk of substance use were identified as being young males. Ethnicity and diagnosis also had an effect on the likelihood of substance use. doi:10.1016/j.schres.2007.12.154 88 – CRANIOFACIAL DYSMORPHOLOGY AND CORTICAL THICKNESS IN SCHIZOPHRENIA B.D. Kelly 1,2 , G. Lawyer 3 , T.F. McNeil 4,5 , K.M. Henriksson 4 , A. Lane 2 , R. Nesvåg 6 , I. Agartz 3,5,6 . 1 University College Dublin, Mater Misericordiae University Hospital, Ireland 2 Stanley Research Unit, Hospitaller Order of St John of God, Ireland 3 Institute of Psychiatry, University of Oslo, Norway 4 Department of Psychiatric Epidemiology, University Hospital, Lund University, Sweden 5 Department of Clinical Neuroscience, Human Brain Informatics (HUBIN), Karolinska Institutet and Hospital, Sweden 6 Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway Presenting Author details: brendankelly35@gmail.com Mater Misericordiae University Hospital, 63 Eccles St, 7 Dublin, Ireland, Tel.: +353 1 8034474; fax: +353 1 8309323. 69 ABSTRACTS / Schizophrenia Research 98 (2008) 3–199