Novel psychoactive substances (NPS) as a risk factor for psychosis: a systematic review of the literature

Novel psychoactive substances (NPS) are increasingly used by young individuals for their psychoactive effects and have been frequently associated with the emergence of psychotic symptoms and schizophrenia spectrum disorders. However, it remains unclear whether NPS use directly increases the risk of psychosis onset or whether individuals with a predisposition to psychosis are more likely to engage in NPS use. This systematic review aims to explore the relationship between NPS consumption and the risk of developing psychotic symptoms. Out of 4477 identified studies, 95 met the inclusion criteria. Findings indicate that synthetic cannabinoids are the most frequently implicated substances, showing a strong association with acute psychosis and, in some cases, with persistent or relapsing psychotic disorders. The presence of Schneiderian First Rank Symptoms in some cases highlights a phenomenological overlap with schizophrenia, suggesting a possible risk of transition.. Synthetic cathinones, phenethylamines, and other NPS classes were also linked to a broad range of psychotic manifestations, including disturbances in thought content and perceptual abnormalities. Although many episodes appeared transient, a notable proportion evolved into persistent psychotic states, supporting the hypothesis that NPS may either unmask latent vulnerabilities or directly contribute to the development of chronic psychotic disorders. These results underline the critical importance of systematically assessing NPS use in individuals presenting with first episode psychosis and call for increased clinical and public health awareness regarding the psychiatric risks associated with these substances.