17.1 a Randomized Controlled Trial of Cannabidiol in Schizophrenia

Abstract

BackgroundBoth preclinical and human research suggest that cannabidiol (CBD) has antipsychotic properties. This study assessed the safety and effectiveness of CBD in patients with schizophrenia.MethodsPatients with schizophrenia (n=88) were randomized to receive CBD (1000 mg/day) or placebo alongside their existing antipsychotic medication for 6 weeks. Participants were assessed before and after treatment using the PANSS, BACS, GAF scales, and the CGI Improvement and Severity scales.ResultsCompared those given placebo, patients treated with CBD had lower levels of positive psychotic symptoms (PANSS; p=0.02), and were more likely to have been rated by clinicians as improved (CGI-I; p=0.02) and as not severely unwell (CGI-S; p=0.04). Patients who received CBD also showed trends for greater improvements in cognitive performance (BACS; p=0.07) and in overall functioning (GAF; p=0.08). There was no difference in the frequency of CBD of adverse events between CBD and placebo.DiscussionThese data suggest that CBD has beneficial effects in patients with schizophrenia and is not associated with significant adverse effects.

Cannabidiol: A budding industry!

“…In the second, more recent randomised controlled trial (n = 36), there was no difference in patient scores for symptoms of schizophrenia or cognitive function for those receiving 600 mg/day of CBD for 6 weeks, compared with placebo (Boggs et al 2018b). In contrast, in the third study, patients (n = 88) given a higher dose (1000 mg/ day) of CBD for a 6-week period exhibited improved scores for psychotic symptoms, relative to the placebo group, and were more likely to be rated by physicians as showing an overall improvement in their condition and having a decreased severity of illness (McGuire et al 2018). Although inconsistent, the results from these early phase trials indicate that CBD may be useful as an adjunctive therapy in the treatment of schizophrenia.…”

“…; McGuire et al . ). In the first study (randomised, double‐blinded), patients ( n = 39) received 200 mg/day of CBD or an active control (amisulpride, an antipsychotic medication) once a day for an initial 1‐week period, after which the doses of CBD were increased in individuals (if tolerated) up to four times per day (800 mg/day), followed by maintenance of the attained dosage for a further 3 weeks (Leweke et al .…”

“…In contrast, in the third study, patients ( n = 88) given a higher dose (1000 mg/day) of CBD for a 6‐week period exhibited improved scores for psychotic symptoms, relative to the placebo group, and were more likely to be rated by physicians as showing an overall improvement in their condition and having a decreased severity of illness (McGuire et al . ). Although inconsistent, the results from these early phase trials indicate that CBD may be useful as an adjunctive therapy in the treatment of schizophrenia.…”

“…Schizophrenia is a severe long-term mental health condition characterised by a range of symptoms, including delusions, hallucinations, blunted emotions and social withdrawal (NHS 2016). Three randomised controlled trials have evaluated the effects of chronic doses of oral CBD on symptoms of schizophrenia (Leweke et al 2012;Boggs et al 2018b;McGuire et al 2018). In the first study (randomised, double-blinded), patients (n = 39) received 200 mg/day of CBD or an active control (amisulpride, an antipsychotic medication) once a day for an initial 1-week period, after which the doses of CBD were increased in individuals (if tolerated) up to four times per day (800 mg/day), followed by maintenance of the attained dosage for a further 3 weeks (Leweke et al 2012).…”

Improving Current Treatments for Schizophrenia

“…The selective CB1 receptor antagonist, rimonabant (approved in the EU for weight loss) failed to show improvements in global cognitive function in [Boggs et al, ]. However, a study of an oily solution containing cannabidiol—GWP42003 as adjunctive therapy for schizophrenia reported that 500 mg bid for 5 weeks reduced positive symptoms of psychosis in patients stabilized on antipsychotic therapy [McGuire et al, ]. Additional Phase II studies using cannabinoids are recruiting patients with acute psychosis.…”