INTRODUCTION
Substance misuse persists as a major public health issue worldwide with significant costs for society. For most young people, experimentation with psychoactive substances during adolescence is transient. However, for a group of these can lead to a wide range of social and medical problems that can be maintained during the adult period.

OBJECTIVE
To describe the evolution of the use of substances in the transition from adolescence to adulthood in a group of patients that come from the Adolescent mental Health Center to the Adults mental health Center located in the periphery of Barcelona (Santa Coloma de Gramenet).

METHODS
Cross-sectional descriptive analysis from a total of n = 41 patients  extracted  from the registry of patients that make the transition from Adolescent Mental Health Outpatient Center (CSMIJ) between 2015-2018 to the Adult Mental Health Outpatient Center of Santa Coloma de Gramenet (CSMA Martí i Julià). Included data was completed with electronic medical reports. The descriptive analysis was performed by "IBM SPSS Statistics (Chicago INC)" software.

RESULTS
From a total of 41 patients linked to CSMA from CSMIJ, 22.5% were psychoactive substances users. From the total of users during adolescence, all maintain the use of psychoactive substances during de adulthood except for 1 patient.  From the total of non-users during adolescence, 12.9% become users in the adulthood. Social, economic, family problems, as well as the family substance use disorder (SUD) history, had a different distribution in the different groups.

DISCUSSION
There is a group of patients who make psychoactive substances use that come from Adolescent Mental Health Outpatient Center with a special vulnerability due to more presence of social, economic and familiar risk compared to non-users. Patients who initiate substance use in adulthood have worse social, economic, academic and familiar stability. Likewise prevalence of psychiatric including substance use disorder is higher.
Hence, we should consider developing specific programs to prevent the use of substances in this population and focus on psychosocial care to reduce the impact of these stressors. 
 It should be borne in mind the need for a long prospective study to investigate the initiation and evolution of substance use along life course processes in adolescence and adulthood in order to understand pathways and trajectories of substance use and perform interventions to prevent and reduce harms related to substance misuse.

15 - TRAJECTORIES OF THE USE OF SUBSTANCES IN THE TRANSITION FROM THE ADOLESCENT MENTAL HEALTH CENTER TO THE ADULTS MENTAL HEALTH CENTER; A DESCRIPTIVE STUDY.