Table 3 Human clinical and animal model studies demonstrating the potential of CBD in neurological/neuropsychiatric disorders
Disorder | Study design | Oral dosage (mg/kg) | Outcomes | Author & year of publication |
|---|---|---|---|---|
Inflammation/Pain | Randomized controlled trial of topical CBD for the treatment of thumb basal joint arthritis | 6.2Â mg/mL | Notable improvements in thumb basal joint arthritis-related pain | (Heineman et al. 2022) |
Double-blind randomized crossover trial of 24 patients with pain associated with a neurological diagnosis | 2.5 – 120 | Pain reduction | (Hunter et al. 2018) | |
Double-blind, randomized, placebo-controlled single-patient cross-over trials to determine if CBD can relieve neurogenic symptoms | 50 – 150 | Significant decrease in pain | (Wade et al. 2003) | |
Open-label study of 12 participants with severe somatoform and dysautonomia syndrome following human papillomavirus vaccination | 150 | Improved vitality and physical component scores | (Cuñetti et al. 2018) | |
Examination of the efficacy of transdermal CBD for reduction of inflammation and pain in Sprague–Dawley rats | 0.6 – 62.3 | Reduced inflammation and pain-related behaviours | (Hammell et al. 2016) | |
Post-traumatic stress disorder (PTSD) | An open-label trial was conducted on 11 patients with PTSD | 22 – 28 oral capsules or 1.5 spray | Reduced PTSD symptoms in 10 patients | (Elms et al. 2019) |
The effect of CBD on PTSD-like behaviours in mice was investigated in adult male C57BL/6Â J mice | 10 | CBD produced anti-PTSD-like actions, attenuated trauma-related fear memory and anxiety-like behaviour | (Han et al. 2022) | |
Schizophrenia | A double-blind study of patients with schizophrenia treated with CBD and amisulpride | 200 | Reduced symptoms with less weight gain and minimal increase in prolactin | (Leweke et al. 2012) |
A double-blind study of patients with schizophrenia treated with CBD in conjunction with the psychotic treatment | 1000 | Decreased psychotic symptoms | (McGuire et al. 2018) | |
Administration of CBD during peri-adolescence stage to determine its ability to prevent schizophrenia-like behavioural activities in an animal model of schizophrenia (Wistar rats and spontaneously hypertensive rat-SHR) | 0.5 – 10 | CBD prevented SHR’s hyperlocomotor activity and cognitive schizophrenia symptoms | (Peres et al. 2018) | |
Substance Abuse and withdrawal | Double-blind placebo-controlled study in which Epidiolex was administered to abstinent heroin users | 400/800 | Reduced cue-induced heroin craving and anxiety | (Hurd et al. 2019) |
Double-blind placebo-controlled study: inhaler containing CBD was administered to cigarette smokers | 0.4 | Reduction in the number of cigarettes consumed after 7Â days | (Morgan et al. 2013) | |
A double-blind crossover study in which 30 cigarette-smoking participants were given oral CBD capsules | 800 | Reduced pleasantness of cigarettes | (Hurd et al. 2019) | |
An open-label study including 8 cannabis users | 600 – 1200 | Cannabis abstinence was observed in 4 out of 8 patients | (Pokorski et al. 2017) | |
Insomnia | Large retrospective case series: CBD was applied clinically as an adjunctive treatment to 25 adult patients | 25 – 75 | Sleep scores improved within the first month of administration | (Shannon et al. 2019) |
Case report: CBD oil was singularly administered to a 10-year-old female patient | 25 | Symptoms of insomnia were suppressed during administration | (Shannon and Opila-Lehman 2016) | |
Case report: administration of CBD oil adjunctively to a 20-year-old patient with insomnia for a duration of six months | 200 – 800 | Increased duration of sleep | (Berger et al. 2020) | |
CBD was administered to male Wistar rats to determine its effects on sleep | 10 µg | CBD administered during lights-on period caused a decrease in rapid eye movement sleep and an increase in wakefulness. No sleep changes were observed in the dark period | (Murillo-RodrÃguez et al. 2006) | |
Anxiety | Randomized, crossover, double-blind, placebo-controlled study: CBD was administered to 10 patients with social anxiety disorder | 400 | Suppressed anxiety in patients | (Crippa et al. 2011) |
Double-blind placebo-controlled study: CBD was tested for anxiolytic properties in 40 participants | 300 | Attenuated anxiety | (Zuardi et al. 1993) | |
Randomized double-blind placebo-controlled trial: To investigate the anxiolytic effects of CBD in 60 participants | 100, 300 and 900 | Reduced anxiety in patients treated with 300Â mg CBD but the reverse was the case with 100Â mg and 900Â mg | (Linares et al. 2018) | |
A large case series: CBD administered to 72 patients with anxiety concerns | 27 – 75 | Anxiety scores decreased from the first month through the course of treatment in 57 patients | (Shannon et al. 2019) | |
The behavioural effects of CBD were investigated in male Fmr1 KO mice | 5 or 20 | Reduced anxiety-like behaviour in mice | (Zieba et al. 2019) | |
Seizures/Epilepsy | Open-label interventional trial: CBD was administered to 214 patients (1–30 years) with severe, intractable, childhood-onset, treatment-resistant epilepsy Double-blind, placebo-controlled trial: CBD administered to 120 children and young adults with Dravet syndrome | 2 – 50 20 | Reduction in the frequency of seizures. Reduction in the frequency of convulsive seizures | |
Prospective multi-centre open-label study on 55 adults and children (1–30 years) with Dravet syndrome | 5 – 50 | Monthly convulsive seizure decreased by 59.1% at week 48 | (Devinsky et al. 2018) | |
A prospective open-label study of 40 patients (1–17 years) with drug-resistant epilepsy | 5 – 25 | Significant improvement was reported in 12 patients while others developed either serious complications or withdrew from the study | (Chen et al. 2018) | |
A prospective multi-centre open-label study involving 607 participants (average of 13 years) with drug-resistant epilepsy | 2 – 50 | Reduction in the frequency of convulsive seizures | (Szaflarski et al. 2018) | |
Retrospective study of 210 patients with epilepsy | 2.9 – 5.8 | Reduced frequency of convulsive seizures | (Porcari et al. 2018) | |
The anti-seizure effect of CBD was investigated in mice and rat model of pilocarpine-induced status epilepticus | 10 | CBD attenuated maximum seizure severity | (Patra et al. 2019) | |
The effect of cannabidiol on seizure was investigated in a mouse model of Dravet syndrome | 100 – 200 | Reduced seizures and autistic-like social deficits | (Kaplan et al. 2017) | |
Parkinson’s disease (PD) | Case report: The effects of CBD in patients receiving treatments for PD and psychosis was examined | 75 – 300 | Quality of life was improved, especially in the group given 300 mg/kg oral CBD | (Chagas et al. 2014) |
The consequences of chronic CBD treatment were examined on neurodegenerative and neuroinflammatory processes, and motor deficits in a classic toxic model of PD | 10 | Reduction of nigrostriatal degeneration, improvement of motor performance, and damping of the neuroinflammatory response | (Giuliano et al. 2021) | |
A case series involving four PD patients with rapid eye movement sleep behaviour disorder (RBD) | 150 – 300 | Significant reduction in the frequency of RBD | (Rieder 2020) | |
Double-blind placebo-controlled clinical trial of the efficacy and safety of CBD for RBD in PD | 75 – 300 | Substantial improvement in sleep satisfaction | (de Almeida et al. 2021) | |
Effects of chronic CBD treatment was evaluated on PD-associated neurodegenerative and neuroinflammatory processes | 10 | CBD enhanced the endogenous neuroprotective response of ciliary neurotrophic factor | (Giuliano 2021) | |
The effect of CBD on PD in a transgenic mouse model was investigated | Â | CBD protected the substantia nigra and significantly improved motor deficits of PD model | (Zhao et al. 2022) | |
Huntington’s disease | Double-blind, randomized cross-over design: a controlled clinical trial of CBD in Huntington’s disease | 10 | No significant effect nor toxic effects were observed | (Consroe et al. 1991) |
The neuroprotective effects of cannabinoids including CBD was examined in male Sprague–Dawley rats | 5 | CBD prevented 3NP-induced striatal damage (relevant for Huntington’s disease) | (Sagredo et al. 2007) | |
Depression/Mood disorder | An observational study to assess the effect of CBD users with anxiety and/or depression | 0.8 | Reduction in self-reported depression as well as improved quality of life was reported | (Martin et al. 2021) |
The antidepressant-like effects of CBD were examined in male Swiss mice | 3 – 100 | At 30 mg/kg, CBD reduced immobility time in forced swimming test conducted | (Zanelati et al. 2010) | |
The anti-depressant effect of CBD was investigated in rat model of depression (Wistar-Kyoto rat) | 15 – 45 | CBD caused an increased locomotion showing improvement in low motivation of the rats to explore | (Shoval et al. 2016) | |
Cognitive impairment | Randomised double-blind, parallel- group and placebo-controlled clinical trial to determine the effect of CBD on cognitive function | 400 and 800 | CBD had no significant cognitive effect | (Lees et al. 2023) |
Randomised, double-blind, placebo-controlled trial to evaluate the efficacy of CBD on cognitive deficits | 800 | No significant evidence | (Rizkallah et al. 2022) | |
Randomised, double-blind, placebo-controlled trial to determine the effect of CBD on cognitive impairment and THC-elicited psychosis | 600 | CBD preserved hippocampal-dependent memory and decreased THC-elicited psychotic symptoms | (Englund et al. 2013) | |
The memory-rescuing effects of cannabidiol was examined in memory-impaired male Wistar rats | 5 or 10 | Memory recovery and improved recognition memory | (Fagherazzi et al. 2012) | |
The potential of CBD in the prevention of hippocampal neurodegeneration and cognitive deficits caused by brain ischemia in male Swiss albino mice was investigated | 3, 10 and 30 | CBD prevented neuronal death caused by ischemia | (Schiavon et al. 2014) | |
Dementia/Alzheimer’s disease | Double-blind placebo-controlled clinical trial to determine the efficacy of CBD in the treatment of early-stage dementia when administered daily over a period of 12 weeks | 200 – 300 | Improved quality of life, prognoses, and treatment outcomes | (Bartschi et al. 2023) |
A Placebo controlled randomized double-blind clinical trial to study the effects of CBD oil on behavioural disturbances in patients suffering from dementia | 295 | Improvements in patients, reduction in sleep disturbances, reduced agitation, and aggression | (Hermush et al. 2022) | |
The effects of long-term administration of CBD on learning and anxiety was examined in female Alzheimer’s disease mouse model | 20 | Spatial learning enhancing effect was caused by CBD | (Chesworth et al. 2022) |