[Use of psychoactive substances as a treatment for psychosis]

Psychotic disorders are considered chronic mental health issues. Although it has been demonstrated that these disorders can present with a wide range of symptoms, pharmacological treatment is based on the use of typical and atypical antipsychotics, whose main mechanism of action is dopaminergic blockade, limiting their effect to the improvement of positive symptoms, without improving the rest of the symptoms and giving rise to a large number of serious adverse effects. For this reason, new therapeutic targets other than the dopaminergic system are being studied. The main objective of this review is to test whether these psychoactive substances used in clinical practice could provide additional benefits as an adjunctive treatment for people with psychotic disorders.

For this systematic review, a literature search was conducted in the databases PsycINFO, Medline, Psicodoc, PubMed and Google Scholar. Altogether 28 articles were included in the review. One of the main findings is that cannabidiol is more effective for improving positive symptoms and psychopathology; modafinil, for cognitive symptoms, motor and emotional functioning and quality of life; and ketamine, for negative symptoms. In addition, all the substances showed a good tolerability and safety profile, especially in comparison to antipsychotics.

The results obtained open up the possibility of having a guideline for clinicians/health professionals on the use of cannabidiol, modafinil and ketamine as adjunctive treatment for patients with psychotic conditions.