Table 4.

Published clinical trials and case series evaluating the effects of cannabidiol in schizophrenic patients.

Design	Primary efficacy endpoint	Outcome	Reference
Single case report, open-label, treatment-resistant schizophrenia, up to 1500 mg/day CBD over 4 weeks	Psychotic symptoms (BPRS; IOSPI)	Improvement in a treatment-resistant patient	Zuardi et al., 1995
Open-label, case series (three patients), treatment-resistant schizophrenia, up to 1280 mg/day CBD over 30 days	Psychotic symptoms (BPRS)	One patient showed mild improvement in positive and negative symptoms	Zuardi et al., 2006
Double-blind, active controlled acute trial, single CBD (300 or 600 mg) or placebo administration	Stroop Color Word Test (SCWT)	No beneficial effects of single CBD administration on cognitive performance of schizophrenic patients	Hallak et al., 2010
Double-blind, active-controlled RCT with 42 acute schizophrenic patients, 600–800 mg/day over 4 weeks	Psychotic symptoms (PANSS/BPRS)	Significant clinical improvement compared to baseline on days 14 and 28 for CBD and amisulpride. Superior side-effect profile for CBD compared to amisulpride	Leweke et al., 2012

BPRS, Brief Psychiatric Rating Scale; CBD, cannabidiol; IOSPI, Interactive Observation Scale for Psychiatric Inpatients; PANSS, Positive and Negative Syndrome Scale; RCT, randomized clinical trial.