DESKcohort is a project led by Universitat de Vic – Universitat Central de Catalunya with the support of General Subdirectorate of drug addiction of the Public Health Agency of Catalonia and the Education Department. Catalan Public Health Agency, the Universitat Oberta de Catalunya, the Center of Epidemiological studies on sexually transmitted infections and AIDS in Catalonia, and Manresa’s city council also collaborate in this project.