S99. CANNABIS USE, PSYCHOTIC-LIKE EXPERIENCES AND ABERRANT SALIENCE IN A SAMPLE OF BELGIAN STUDENTS

Abstract Background Cannabis is the most popular illicit drug in the western world and its use seems to be strongly associated with an increased risk of developing schizophrenia and other psychotic disorders. Its use can induce transient psychotic symptoms in healthy individuals and increase rate of subclinical psychotic symptoms in the general population. Subclinical psychotic experiences (also called Psychotic Like Experiences: PLEs), such as magical thinking, paranoid ideation or hallucinations, could be considered as a phenotype qualitatively similar to the symptomatology of psychotic disorders but quantitatively less severe in terms of intensity, frequency and impairment. They are fairly common in the general population and usually transitory and self-limiting but they could become abnormally persistent and evolve to a full-blown psychotic disorder, especially if combined with certain environmental risk factors, such as trauma, urbanicity, cannabis use. PLEs may be considered as an early marker of a latent psychosis vulnerability and the frequently good outcome of subclinical psychosis can be turned in negative outcomes by the association with environmental risk factors, such as cannabis use. We focus our attention on aberrant salience, a peculiar psychotic experience, frequently reported during the prodromal phase that precede the onset of full-blown psychotic illness. Aberrant salience is the unusual or incorrect assignment of salience or significance to innocuous stimuli; it has been hypothesized to be an important mechanism in the development of psychosis. Methods Undergraduate students of ULB (Universitè Libre de Bruxelles) and INSAS (Institut national supérieur des arts du spectacle) of Brussels (Belgium) were invited to participate to the study. A self-report questionnaire, investigating socio-demographic characteristics, and cannabis use was administered, evaluating lifetime and current cannabis use. Aberrant Salience Inventory (ASI) is a 29 item Yes–No questionnaire developed to evaluate aberrant salience. French version of Community Assessment of Psychic Experiences (CAPE), was used to evaluate dimensions of psychosis and PLEs. CAPE is a 42-item, self-report questionnaire, developed to measure the lifetime prevalence of PLEs in the general population. The questionnaire assesses three symptom dimensions (positive, depressive and negative symptoms). All statistical analysis was carried out with Statistical Package for Social Sciences, Version 20.0. We evaluated individual correlations between years of cannabis use and days of cannabis use in the last month with the tools scores. We also explored correlation of ASI score with different CAPE scores and different types of PLEs. Correlations were carried out by using the nonparametric Spearman correlation test. Results The final sample was of 257 participants. 46,3% of subjects reported a lifetime cannabis use and 35.0% reported a current cannabis use (last 30 days). Compared with non-users, cannabis users showed significant higher ASI scores and also higher positive and negative dimensions CAPE scores. No significant association was found between cannabis consumption and the depressive dimension of CAPE. Years of cannabis use and frequency of use in the last 30 days showed a small positive correlation with ASI score; also, weaker positive correlations with CAPE positive and negative dimensions scores were observed. Discussion To some extent, our results support the evidences that cannabis use is associated with an increased rate of psychotic experiences in individuals without clinical form of psychosis. Future prospective longitudinal studies are required to better investigate the meaning of the association between cannabis use and PLEs.

no established social anxiety treatments.Social anxiety is associated with decreased quality of life (Hansson, 2006), low self-esteem (Gumley et al., 2005), and increased psychopathology (Vrbova et al., 2017).Lysaker and Hammersley (2006) found that people with delusions and impairment in flexibility had the highest levels of social anxiety compared to those with fewer symptoms.Additionally, Lysaker et al. (2010) found that people with both high paranoia and theory of mind had higher social anxiety compared to those with lower levels of either paranoia or theory of mind.Taken together, this research suggests that symptoms may increase social anxiety, but other factors may inhibit their impact.The current study aims to add to this literature by exploring how different levels of hallucinations and self-esteem support affect social anxiety in SCZ.Methods: Outpatients with SCZ (N=50) participated in the current study.Participants were 76% male with a mean age of 42.50.Participants were African-American (n=27; 54%), Caucasian (n=11; 22%), multi-racial (n=5; 10%), Asian (n=4, 8%), or Hispanic (n=3; 6%).Social fear, social avoidance, and overall social anxiety was measured with the Liebowitz Social Anxiety Scale (LSAS;Liebowitz, 1987).Self-esteem support (SeS) was measured with a subscale taken from the Interpersonal Support Evaluation List (ISEL;Cohen & Hoberman, 1983).SeS is the appraisal of the self compared with others and other's opinions of the self.Hallucinations (HA) were scored with the observer-rated Scale for Assessment of Positive Symptoms (SAPS;Andreasen, 1983).Participants were classified as having hallucinations if their SAPS global hallucinations were rated moderate to severe.This was chosen a priori as it reflects a level of clear hallucinations that may bother the person to some extent, as defined within the SAPS.Participants were classified as having either high or low SeS based on a mean split of the distribution of scores.Once participants were classified, we planned to compare groups on levels of social anxiety.This method was modified from previous research reporting similar groupings of symptoms and their relationship to social anxiety (Lysaker & Hammersley, 2006).Results: Four groups resulted after including the dichotomized variables with the following proportions: low SeS/no HA (n=6; 12.5%), low SeS/HA (n=11, 22.9%), high SeS/no HA (n=13; 27.1%), and high SeS/HA (n=18, 37.5%).A one-way ANOVA was conducted to analyze the differences between groups.Post-Hoc analyses revealed the following differences.The HA/low SeS group had higher social anxiety than in the no HA/high SeS group (p=.030) and no HA/low SeS group (p=.039).The HA/low SeS group had higher social fear (p=.017) and social avoidance (p=.013) than in the no HA/high SeS group.There was a trending difference revealing that participants in the HA/low SeS group had higher social avoidance than in the HA/high SeS group (p=.056).There was a trending difference revealing that the HA/low SeS group had greater overall social anxiety than those in the HA/high SeS group (p=.064).Discussion: These results present preliminary findings on social anxiety in people with different levels of HA and SeS.We found that people with low SeS and HA had significantly higher levels of social anxiety, social fear, and social avoidance than participants with only one of neither of these symptoms.These results will be discussed further to highlight implications to treatment and comorbidities in SCZ.

S99. CANNABIS USE, PSYCHOTIC-LIKE EXPERIENCES AND ABERRANT SALIENCE IN A SAMPLE OF BELGIAN STUDENTS
Francesco Bernardini* ,1 , Chiara Gobbicchi 2 , Luigi Attademo 3 , Severin Puchalski 1 , Patrizia Moretti 2 , Alfonso Tortorella 2 , Gwenole Loas 4 1 Free University of Brussels; 2 Università degli Studi di Perugia; 3 ASP Basilicata; 4 Erasme Hospital Background: Cannabis is the most popular illicit drug in the western world and its use seems to be strongly associated with an increased risk of developing schizophrenia and other psychotic disorders.Its use can induce transient psychotic symptoms in healthy individuals and increase rate of subclinical psychotic symptoms in the general population.Subclinical psychotic experiences (also called Psychotic Like Experiences: PLEs), such as magical thinking, paranoid ideation or hallucinations, could be considered as a phenotype qualitatively similar to the symptomatology of psychotic disorders but quantitatively less severe in terms of intensity, frequency and impairment.They are fairly common in the general population and usually transitory and self-limiting but they could become abnormally persistent and evolve to a full-blown psychotic disorder, especially if combined with certain environmental risk factors, such as trauma, urbanicity, cannabis use.PLEs may be considered as an early marker of a latent psychosis vulnerability and the frequently good outcome of subclinical psychosis can Poster Session III be turned in negative outcomes by the association with environmental risk factors, such as cannabis use.We focus our attention on aberrant salience, a peculiar psychotic experience, frequently reported during the prodromal phase that precede the onset of full-blown psychotic illness.Aberrant salience is the unusual or incorrect assignment of salience or significance to innocuous stimuli; it has been hypothesized to be an important mechanism in the development of psychosis.Methods: Undergraduate students of ULB (Universitè Libre de Bruxelles) and INSAS (Institut national supérieur des arts du spectacle) of Brussels (Belgium) were invited to participate to the study.A self-report questionnaire, investigating socio-demographic characteristics, and cannabis use was administered, evaluating lifetime and current cannabis use.Aberrant Salience Inventory (ASI) is a 29 item Yes-No questionnaire developed to evaluate aberrant salience.French version of Community Assessment of Psychic Experiences (CAPE), was used to evaluate dimensions of psychosis and PLEs.CAPE is a 42-item, self-report questionnaire, developed to measure the lifetime prevalence of PLEs in the general population.The questionnaire assesses three symptom dimensions (positive, depressive and negative symptoms).All statistical analysis was carried out with Statistical Package for Social Sciences, Version 20.0.We evaluated individual correlations between years of cannabis use and days of cannabis use in the last month with the tools scores.We also explored correlation of ASI score with different CAPE scores and different types of PLEs.Correlations were carried out by using the nonparametric Spearman correlation test.

Results:
The final sample was of 257 participants.46,3% of subjects reported a lifetime cannabis use and 35.0% reported a current cannabis use (last 30 days).Compared with non-users, cannabis users showed significant higher ASI scores and also higher positive and negative dimensions CAPE scores.No significant association was found between cannabis consumption and the depressive dimension of CAPE.Years of cannabis use and frequency of use in the last 30 days showed a small positive correlation with ASI score; also, weaker positive correlations with CAPE positive and negative dimensions scores were observed.Discussion: To some extent, our results support the evidences that cannabis use is associated with an increased rate of psychotic experiences in individuals without clinical form of psychosis.Future prospective longitudinal studies are required to better investigate the meaning of the association between cannabis use and PLEs.

S100. EFFECTS OF CANNABIS USE ON BODY MASS, FASTING GLUCOSE AND LIPIDS DURING THE FIRST 12 MONTHS OF TREATMENT IN SCHIZOPHRENIA SPECTRUM DISORDERS
Frederika Scheffler* ,1 , Sanja Kilian 1 , Bonga Chiliza 1 , Laila Asmal 1 , Lebogang Phahladira 1 , Stefan du Plessis 1 , Martin Kidd 1 , Robin Murray 2 , Marta Di Forti 2 , Soraya Seedat 1 , Robin Emsley 1 1 Stellenbosch University; 4 Institute of Psychiatry, King's College, London Background: Acute cannabis use stimulates appetite, while general population studies suggest that chronic use is associated with reduced risk of obesity and other cardiometabolic risk factors.Methods: In this study, we investigated changes in body mass index (BMI), fasting blood glucose and lipids, and rates of metabolic syndrome risk factors in cannabis users vs. non-users in 109 minimally treated patients with first-episode schizophrenia, schizophreniform or schizo-affective disorder who were treated according to a standardized treatment regime with depot antipsychotic medication over 12 months.Participants underwent repeated urine toxicology tests for cannabis and those testing positive at any time during the study (n=40), were compared with those who tested negative at all time points (n=69).Results: There was a significant group*time interaction effect (p=0.002) with the cannabis negative group showing a greater increase in BMI than the cannabis positive group, after adjusting for age, sex, methamphetamine use and modal dose of antipsychotic.There were no group*time interaction effects for fasting blood glucose or lipids.Post hoc tests indicated significant increases in fasting blood glucose and triglycerides and a decrease in high-density lipoprotein cholesterol for the cannabis negative group, with no significant changes in the cannabis positive group.Rates of metabolic syndrome did not differ significantly between groups.However, more cannabis negative patients had elevated waist-circumference at endpoint (p=0.003).Discussion: Although other indirect effects such as dietary neglect and smoking may be contributory and could explain our findings, it may be that chronic cannabis use directly suppresses appetite, thereby preventing weight gain in users.

S101. CLINICAL FACTORS ASSOCIATED WITH CANNABIS USE IN A CHILEAN SAMPLE OF FIRST EPISODE PSYCHOSIS PATIENTS
Barbara Iruretagoyena* ,1 , Nicolas Crossley 1 , Alfonso Gonzalez-Valderrama 2 , Cristian Mena 2 , Carmen Castañeda 2 , Camila Diaz 2 , Juan Undurraga 2 1 Universidad Católica de Chile; 2 J. Horwitz Psychiatric Institute Background: Cannabis has been associated with higher risk to develop psychosis and worse long-term outcomes.Cannabis use in 2016 is estimated to be 11.3% in Chile in 2016 (SENDA 2016).As in many other countries, cannabis use has steadily increased during last 20 years, across all socioeconomic groups, but especially in men and in the group aged 12 to 25 years old.At the same time, 5.7% subjects declared using high potency cannabis.We here examined the frequency of cannabis use in patients with a first episode psychosis in Chile.We also sought to identify etiologic factors associated with cannabis use, as well as its impact on clinical and functional status.Methods: We performed a cross-sectional study on patients from an outpatient Early Intervention in Psychosis unit in Chile.Data included sociodemographic characteristics, cannabis and other substance use, and standardized clinical and functional status.FAST (Functional Assessment Short Test), SS-DSM5 (Symptom Severity Scale of the DSM5 for Schizophrenia), CUPIT (Cannabis use Problem Identification Scale) and MG (Morinsky Green Adherence Questionnaire) were applied to the participants.Results: We included 80 patients, of which 23.8% used cannabis during the previous year.47.3% of cannabis users had used cannabis with high THC concentration.63.2% of consumers had a moderate-high score in the CUPIT scale, indicating a high prevalence of risk consumption and use disorder.Regarding variables related with cannabis use, correlation analysis showed a significant relationship with alcohol use (p<0.001),drug use (p<0.001) and duration of untreated psychosis (p=0.039,all corrected for multiple analysis.).Multivariate regression analyses including these variables along with gender and age, only showed relation with drug use (p=0.031,.Regarding cannabis use and clinical and functional outcomes, correlation analysis showed association with adherence problems as reported by physician (p= 0.026) and the Morinsky Green Adherence Questionnaire (p= 0.031).Results showed an  for adherence problems and OR 0.2 (0.05-0.75) for Morinsky Green Adherence Questionnaire reporting good adherence.There was no effect in treatment resistance, FAST score, SS-DSM5 global, cognitive or negative score.Discussion: The percentage of cannabis use in this first episode psychosis sample is high, with a large subgroup using high potency THC cannabis.Cannabis use was associated to other drug use and to treatment adherence problems reported by physician and patient.This shows the importance of substance use treatment in first episode programs.