Effects of cannabidiol as an adjunctive therapy in patients with a first episode of psychosis: a prospective randomized controlled clinical trial

Abstract

BACKROUND: People suffering from psychosis exhibit a wide variety of symptoms, such as hallucinations or delusions, which lead to feel fear, distress and isolation. In our environment the annual incidence of FEP is about 31.6/100,000 in population aged ≥ 15 years. Also, it causes damage to family members and friends, who feel powerless in this situation and may have to carry the emotional and physical burden of care. In recent years there has been controversy in the role of two of the main components of cannabis sativa plant in psychotic disorders: THC and CBD. Several studies done last years have been proved that CBD can have antipsychotic properties based on the capacity to directly inhibit the reuptake of anandamide and also reduce endocannabinoids degradation by blocking fatty acid amide hydrolase function. The result of this is an increasing level of anandamide that it is studied that can alleviate psychotic symptoms. OBJECTIVE: The main objective of this study is to determine the efficacy of the CBD using them as an adjunctive therapy in standard antipsychotic treatment with Risperidone in patients who are diagnosed with a first episode of psychosis, compared to those patients who only receive the standard treatment. Secondary objectives will be assessing the neuroprotective effects of CBD treatment in the cognitive impairments associated with FEP and also, the treatment tolerance and side effects of each group. STUDY DESIGN: The study will be a prospective, double-blind, randomized and controlled 6- week clinical trial. It study will be carried out in the Xarxa de Salut Mental i addicions (XSMA) in the Girona region. INTERVENTIONS AND METHODS: Subjects of the study will be those patients over 18 years old newly diagnosed with a first episode of psychosis considering the diagnosis criteria of DSM-V. Candidate patients will be selected as they are admitted to the Unitat d’Hospitalització d’Aguts (UHA) of Parc Hospitalari Marti i Julià (PHMIJ). They will randomly divide in two groups: group 1 (n = 87), patients will be treated with a low dose of an antipsychotic atypical (Risperidone) plus concomitant cannabidiol (CBD); in group 2 (n = 87), patients will receive the same antipsychotic plus concomitant placebo treatment instead of cannabidiol. Psychotic symptoms will be assessed using the Positive and Negative Syndrome Scale (PANSS) at baseline and biweekly. In addition, the cognitive performance will be evaluated by the MATRICS Consensus Cognitive Battery (MCCB) at baseline and at end of 6 weeks of treatment