M25. CLINICAL CORRELATES OF SUBSTANCE USE IN HEALTHY ADOLESCENTS: ASSOCIATIONS WITH PSYCHOTIC EXPERIENCES AND COGNITIVE BIASES

BACKGROUND: Substance use (tobacco, cannabis and alcohol consumption) is associated with the risk of developing a psychotic disorder as well as the risk of presenting psychotic experiences. We aimed to study the associations between substance use and psychotic-like experiences in a sample of healthy adolescents aged between 14 and 15 years. We also aimed to study potential relationships with bullying and cognitive biases. METHODS: A sample of 207 adolescents born in 2004 and studying in high schools from Sabadell. After excluding 33 participants who were receiving mental health care, a final sample of 174 adolescents (102 girls; 72 boys, mean ± standard deviation age: 14.4 ± 0.5 years) was included in the analyses. Before participating in the study, all participants and their parents signed a full written consent. The study was approved by the local Ethics Committee. All participants completed on-line questionnaires to explore psychotic-like experiences (15-item Community Assessment of Psychic Experiences – Positive Scale [CAPE-P15]), cognitive biases (Cognitive Biases Questionnaire for Psychosis [CBQp], with some items adapted for adolescents) and bullying (Adolescent Peer Relations Instrument [APRI]). Substance use was registered for tobacco, cannabis and alcohol consumption (sporadic or continuous). Statistical analysis were conducted with SPSS v 23.0 (IBM, USA). Substance use was recoded in dichotomic variables (use vs no use). All psychometric scales by these two groups were compared with non-parametric tests (U Mann Whitney). A p value <0.05 was considered to be significant. RESULTS: Of all 174 participants, 24 (13.8%) reported tobacco consumption, 49 (28.2%) alcohol consumption and 5 (2.9%) cannabis consumption. Differences in psychometric scales were tested for tobacco and alcohol use. Tobacco use was associated with more cognitive biases (total CBQp score [p=0.036] and dichotomic thinking [p=0.018]) but not with psychotic-like experiences or bullying. Alcohol use was associated with more cognitive biases (total CBQp score [p= 0.033] and jumping to conclusions [p= 0.025]) and more psychotic-like experiences (total CAPE-P15 score [p=0.008] and paranoid ideation subscore [p= 0.002]). Alcohol consumption was not associated with reported bullying. DISCUSSION: Our findings suggest that alcohol use in healthy adolescents aged between 14 and 15 years old is associated with psychotic-like experiences, and that this association could also involve cognitive biases (a ‘jumping to conclusions’ thinking style). Tobacco use was also associated with cognitive biases, although no effect was found on psychotic-like experiences. Bullying did not appear to have a relationship with substance use. Some limitations of our study include the cross-sectional design (no causal relationship might be inferred) and the low proportion of cannabis use. Future longitudinal studies also including a wider range of adolescent ages are needed to overcome our limitations. Our study underscores the need to monitor the potential psychopathological risks of alcohol consumption on adolescents.