as specific symptomology (e.g. depression), suggesting that cannabis may contribute to symptom exacerbation in schizophrenia [116–118]. Interestingly, however, a recent trial by McGuire and colleagues suggests the potential of administering 1000 mg of cannabidiol (CBD) daily for 6 weeks alongside current antipsychotics for reducing positive symptoms as rated by the PANSS, as well as for improving self-reported and clinician-reported functional outcomes in schizophrenia compared to placebo [102]. Moreover, a study by Leweke and colleagues compared the efficacy of CBD to a potent antipsychotic, amisulpride, in acute schizophrenia, describing similar efficacy in clinical symptomatic improvement as well as superior side effects, such as increased anandamide serum levels that were significantly associated with clinical improvements [93]. In a trial similar to McGuire et al.’s, conducted by Boggs and colleagues, 600 mg of CBD was administered daily for 6 weeks and, despite being well tolerated, was not associated with any improvement with symptoms using the PANSS, or with cognition compared to placebo in stable, treated patients with schizophrenia [9]. A systematic review of the therapeutic potential of CBD and higher CBD cannabis preparations for psychosis and schizophrenia describes a promising future with effective and tolerable results thus far [76]. Moreover, published on the
