“Cannabidiol (CBD) has been used as a pharmacological treatment for psychiatric disorders in many studies, but few of good quality at the moment. Our objective was to assess the effect of CBD in mono/add-on therapy on symptom severity in psychiatric disorders. We performed a systematic review of clinical trials and randomized controlled trials that used CBD as treatment for psychiatric disorders. PRISMA criteria have been used for methodological purposes. Two assessors individually examined the results based on title and abstract, and decided which papers warranted full read. We included studies in English that measured disease severity as primary outcome. Out of 226 studies returned from the search, 9 warranted full read. There were 4 studies using CBD in schizophrenia, 3 studies of substance use disorder and 2 studies of social anxiety. CBD has a good safety profile even in higher doses, but results are inconclusive regarding improvements in disease severity.”