This cross-sectional study aims to determine lifetime prevalence of psychiatric disorders (including substance use disorders, -SUD and other non substance use disorders, -Non-SUD) among 289 young (1830 years) regular cannabis users, during the last year, in non-clinical settings in Barcelona. The Spanish version of the Psychiatric Interview for Substance and Mental Disorders (PRISM) was administered. Only 28% of the participants did not present any psychiatric disorder; while 65% had some SUD, the most common related to cannabis use (62%). Nearly 27% presented a non-SUD disorder. A younger age of initiation on alcohol use was associated with the presence of some SUD. Having consumed a greater number of "joints" in the last month was associated with the presence of both psychiatric disorders (SUD and non-SUD). While three quarters of subjects with non-SUD disorders had received some kind of treatment, only 28% of those with any SUD had received treatment. Given the low perception for need of treatment, there is a need for prevention strategies and to be able to offer therapies specifically tailored targeting young cannabis users.