Table 1.
Summary of the studies described in the manuscript
| Article | Study design | Diagnosis | Sample (M/F) | Age (years old) | CBD dosage/formulation | CBD timing | Augmentation | Scales, test and measurements | Main results |
|---|---|---|---|---|---|---|---|---|---|
| Zuardi et al. (1995) | Case report | Treatment-resistant SKZ | 1 (0/1) | 19 | 1500 mg/day of gelatin capsules (with powder CBD dissolved in corn oil) | 4 weeks | Diazepam co-medication allowed | BPRS IOSPI UKU |
Significant reduction of all items of BPRS score No side effects |
| Zuardi et al. (2006) | Case report | Treatment-resistant SKZ | 3 (3/0) | 23 23 22 |
CBD in two daily doses, from 40 mg/day until 1280 mg/day | 29 days | / | BPRS PANSS-N CGI UKU SAS BARS |
Mild or no symptoms improvements No side effects |
| Zuardi et al. (2009) | Open-label pilot study | Parkinson disease with psychotic symptoms | 6 (4/2) | 58.8 ± 14.9 | 150 mg/day up to 400 mg/day of gelatin capsules (with powder CBD dissolved in corn oil) | 4 weeks | Median of 1050 mg/day of L-dopa | BPRS PPQ UPDRS CGI MMSE FAB |
Significant reduction psychotic symptoms. No side effects |
| Hallak et al. (2010) | Double-blinded, placebo-controlled study | SKZ | 28 (18/10) | More than 18 | 300 mg CBD, 600 mg CBD or placebo in gelatin capsules | One single dose | / | BPRS PANSS SCWT |
Single acute administration of CBD did not improve SCWT performances. Possible sedative effect with 600 mg dose |
| Leweke et al. (2012) | Double-blinded, randomised, parallel-group, controlled clinical trial of CBD v. amisulpride | SKZ or schizophreniform psychosis | 20 (15/5) CBD group + 19 (17/2) amisulpride group | 18–50 | 200 mg/day up to 800 mg/day CBD or amisulpride | 4 weeks | Lorazepam co-medication allowed | BPRS PANSS EPS CGI SAS |
Significant clinical improvement in both groups. Anandamide and FAAH substrates levels higher in CBD group. Fewer side effects in the CBD group |
| Leweke (2013) | Double-blind, randomised, placebo-controlled, cross-over clinical trial pf CBD v. | First-episode paranoid SKZ | 29 | NIA | 600 mg/day CBD | 14 days | NIA | NIA | CBD improved psychotic symptoms compared with baseline |
| McGuire et al. (2018) | Double-blind, randomised, placebo-controlled, parallel-group trial | SKZ or a related psychotic disorder | 43 (28/15) CBD group + 45 (23/22) placebo group | 18–65 | 1000 mg/day CBD (10 mL of a 100 mg/mL oral solution) or placebo in two doses | 6 weeks | Antipsychotic medication | PANSS SANS CGI GAF BACS SAS |
Significant reduction of positive symptoms, better cognitive performance and overall functioning in CBD group No significant side-effects. No correlations between CBD plasma levels and scale scores |
| Boggs et al. (2018) | Double-blind, randomised, placebo-controlled, parallel group trial | SKZ | 18 (12/6) CBD group + 18 (13/5) Placebo group | 18–65 | 600 mg/day oral CBD | 6 weeks | Antipsychotic medication | MCCB PANSS |
No improvement in cognitive scores and no reduction of psychotic symptoms |
| Crippa et al. (2011) | Double-blind, randomised, placebo-controlled, repeated measures, within-subjects cross-over trial | Treatment-naïve generalised social anxiety disorder | 10 (10/0) | 20–33 | 400 mg CBD of gelatin capsules (with powder CBD dissolved in corn oil) | One single dose | / | VAMS SPECT |
Significant reduction of subjective anxiety in CBD group Functional activity changes in limbic and paralimbic cerebral regions in CBD group No side effects |
| Bergamaschi et al. (2011) | Double-blind, randomised, placebo-controlled, clinical trial | Treatment-naïve generalised social anxiety disorder | 12 (6/6) CBD group 12 (6/6) place group 12 (6/6) HC |
600 mg CBD in gelatin capsules (with powder CBD dissolved in corn oil) | One single dose | / | VAMS SSPS BSS |
Significant reduction of anxiety symptoms, cognitive impairment and speech performance discomfort in CBD group | |
| Zuardi et al. (2010) | Case report | Bipolar disorder type I, manic episode with psychotic features | 2 (0/2) | 25 17 |
600 mg CBD (up to 1200 mg/day) | 25 days | Olanzapine during the first 2 weeks | BPRS YMRSUKU |
No significant symptoms improvements with CBD. No side effects |
| Crippa et al. (2013) | Case report | Cannabis dependence and cannabis withdrawal syndrome | 1 (0/1) | 19 | 300 up to 600 mg on in gelatin capsules (with powder CBD dissolved in corn oil) | 10 days | / | WDSM WSC BAI BDI |
Reduction of withdrawal, anxiety and dissociative symptoms No significant effect on long-term cannabis dependence |
| Shannon and Opila-Lehman (2015) | Case report | Cannabis dependence, bipolar disorder | 1 (1/0) | 27 | 18 up to 24 mg CBD oil | Prolonged over time | / | PSQI HAM-A |
CBD was effective in quitting cannabis abuse, in reducing anxiety symptoms and improving quality of life |
| Morgan et al. (2013) | Double-blind, randomised, placebo-controlled clinical trial | Tobacco use disorder | 18 (12/6) CBD group 12 (6/6) placebo group |
18–35 | CBD (400 µg dose for each depress of the solution aerosol in the inhaler) via a pressurised metered dose inhaler | 1 week | / | STAI BDI BIS |
Significant reduction of cigarettes smoked in CBD group. No significant effects on craving. No side effects |
BACS, Brief Assessment of Cognition in Schizophrenia; BAI, Beck Anxiety Inventory; BARS, Barnes Akathisia Rating Scale; BDI, Beck Depression Inventory; BIS, Behaviour Impulsivity Scale; BPRS, Brief Psychiatric Rating Scale; BSS, Bodily Symptoms Scale; CBD, cannabidiol; CGI, Global Clinical Impression Scale; EPS, Extrapyramidal Symptoms Rating Scale; FAAH, fatty acid amide hydrolase; FAB, Frontal Assessment Battery; GAF, Global Assessment of Functioning; Hamilton Anxiety Rating Scale; HC, healthy controls; IOPSI, Interactive Observation Scale for Psychiatric Inpatients; MCCB, Matrix Consensus Cognitive Battery; MMSE, Mini-Mental Status Examination; MWSC, Marijuana Withdrawal Symptom Checklist; NIA, no information available; PANSS-N, Negative Subscale of Positive and Negative Syndrome Scale; PPQ, Parkinson Psychosis Questionnaire; PSQI, Pittsburgh Sleep Quality Index; SANS, Scale for Assessment of Negative Symptoms; SAS, Social Anxiety Scale; SAS, Simpson-Angus Scale for Parkinson; SCWT, Stroop Color-Word Test; SKZ, schizophrenia; SPECT, single-photon emission computer tomography; SPSS, Self-Statements during Public Speaking Scale; STAI, Spielberger Trait Anxiety Inventory; UKU, UKU Side Effect Rating Scale; UPDRS, Unified Parkinson's Disease Rating Scale; VAMS, Visual Analogue Mood Scale; WDS, Withdrawal Discomfort Score; YMRS, Young Mania Rating Scale.