The non-intoxicating cannabinoid studied for epilepsy, anxiety, and inflammation, with a pharmacology distinct from THC.
Synthesized from 25 studies in the library · AI-generated, grounded in the abstracts below
Found by searching the library for CBD, cannabidiol, epidiolex, then ranked by relevance.
Research indicates that CBD may reduce anxiety and mitigate some THC-induced effects, such as paranoia and memory impairment, but findings are inconsistent, with some studies showing no benefit or even exacerbation of impairment. Evidence for CBD's therapeutic efficacy in psychiatric conditions is limited, with modest short-term benefits but insufficient support for long-term use. The main caveats include small sample sizes, heterogeneous dosing, and the need for more rigorous, long-term studies.
Direction is which way each study's own result points, not our rating of the study.
| Study | Design | Sample size | Direction | Finding |
|---|---|---|---|---|
| Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment 2012 | randomized controlled trial | 48 | Supports | Pre-treatment with 600 mg oral CBD reduced THC-elicited paranoia and the odds of clinically significant positive psychotic symptoms, and mitigated THC-induced memory impairment. |
| Distinct Effects of Δ9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing 2009 | double-blind, randomized, placebo-controlled crossover trial | 15 | Supports | CBD reduced arousal and dampened limbic brain activation during emotional processing, correlating with its anxiolytic trend. |
| Cannabidiol, a Cannabis sativa constituent, as an antipsychotic drug 2006 | review | Supports | Argues that CBD shows anxiolytic and antipsychotic-like properties and may be a safe alternative treatment for schizophrenia. | |
| Inverted U-Shaped Dose-Response Curve of the Anxiolytic Effect of Cannabidiol during Public Speaking in Real Life 2017 | randomized controlled trial | 60 | Mixed | CBD 300 mg, but not 100 mg or 900 mg, significantly reduced anxiety scores compared to placebo in the post-speech phase, showing an inverted U-shaped dose-response curve. |
| Acute Effects of a Single, Oral dose of d9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) Administration in Healthy Volunteers 2012 | randomized controlled trial | 16 | No effect | CBD showed no differences from placebo on any symptomatic or physiological variable. |
| Modulation of Mediotemporal and Ventrostriatal Function in Humans by Δ9-Tetrahydrocannabinol 2009 | randomized controlled trial | 15 | No effect | Cannabidiol had no significant effects on psychotic symptoms, anxiety, intoxication, sedation, or brain activation during verbal learning. |
| The neuropsychopharmacology of cannabis: A review of human imaging studies 2018 | review | Mixed | Argues that cannabis and THC acutely affect neurocognitive systems, and that CBD may offset some of these acute effects, but heavy adolescent use is linked to increased risk of addiction and psychosis. | |
| Neuroimaging in cannabis use: a systematic review of the literature 2009 | systematic review | Unclear | Functional neuroimaging suggests modulation of global and prefrontal metabolism during rest and after THC/marijuana administration, but evidence for major structural brain changes from cannabis is minimal. | |
| Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition 2019 | randomized, double-blind, within-subjects crossover | 14 | Opposes | Cannabis containing equivalent concentrations of CBD and THC appears no less impairing than THC-dominant cannabis, and CBD may exacerbate THC-induced impairment in some circumstances. |
| Acute and chronic effects of cannabinoids on effort-related decision-making and reward learning: an evaluation of the cannabis ‘amotivational’ hypotheses 2016 | randomized controlled trial | 17 | Mixed | THC-only cannabis acutely reduced high-effort choices, while cannabis dependence was linked to impaired reward learning but not motivation; CBD did not significantly alter these effects. |
| Tolerance and cross-tolerance to neurocognitive effects of THC and alcohol in heavy cannabis users 2010 | double-blind, placebo-controlled, three-way study | 21 | No effect | THC generally did not affect task performance in heavy cannabis users, and CBD was not studied; alcohol potentiated THC effects on divided attention. |
| Modulation of effective connectivity during emotional processing by Δ9-tetrahydrocannabinol and cannabidiol 2009 | randomized controlled trial | 15 | Supports | CBD, but not THC, disrupted forward connectivity between the amygdala and anterior cingulate cortex during the neural response to fearful faces. |
| Neurophysiological and subjective profile of marijuana with varying concentrations of cannabinoids 2005 | randomized controlled trial | 23 | No effect | Varying concentrations of CBD did not change subjective, behavioral, or neurophysiological responses to smoked marijuana. |
| Cannabis, a cause for anxiety? A critical appraisal of the anxiogenic and anxiolytic properties 2020 | systematic review | Supports | Acute doses of CBD were found to reduce anxiety both in animals and humans, without having an anxiogenic effect at higher doses. | |
| Performance of schizophrenic patients in the Stroop Color Word Test and electrodermal responsiveness after acute administration of cannabidiol (CBD) 2010 | randomized controlled trial | 28 | Opposes | Single acute doses of CBD did not improve Stroop test performance in schizophrenic patients, and 600 mg was associated with worse performance compared to placebo or 300 mg. |
| Cannabis and Mental Health: A Systematic Review and Meta-analysis of the Neuropsychiatric Effects, Therapeutic Potentials, and Policy Implications of THC and CBD 2026 | systematic review and meta-analysis | 14 | Mixed | CBD demonstrated potential antipsychotic, anxiolytic, and neuroprotective effects, but evidence for cannabis-based products in treating psychiatric disorders was limited, with modest short-term benefits but insufficient support for long-term efficacy. |
| Acute behavioural effects of low-dose cannabidiol: A randomised crossover trial in healthy volunteers. 2026 | randomized controlled trial (crossover) | 70 | Supports | A 200 mg dose of synthetic CBD produced a 12.8% higher peak pleasant drug effect score than placebo, while lower doses (20, 50, 100 mg) showed no significant effect. |
| Prophylactic efficacy of cannabidiol and sodium nitroprusside in a ketamine model of schizophrenia: sex-dependent effects on positive-like and cognitive impairments 2026 | animal study | Supports | The combination of CBD and sodium nitroprusside reduced hyperlocomotion and prevented novel object recognition deficits in both sexes in a ketamine rodent model of schizophrenia, with superior prophylactic effects in females. | |
| Psychedelic-Assisted Psychotherapy for the Treatment of PTSD: A Systematic Review and Meta-Analysis 2026 | systematic review and meta-analysis | 358 | No effect | A single CBD trial showed no clear benefit for PTSD symptom reduction. |
| Effects of THC, CBD, and Their Combination on EEG Dynamics in Rats. 2026 | experimental study | Mixed | Acute THC and THC+CBD, but less so CBD alone, increase low-frequency EEG power and alter functional connectivity in CB1 receptor-rich brain regions of freely moving rats. | |
| Effect of cannabinol, tetrahydrocannabivarin and cannabidiol on voluntary alcohol consumption. 2026 | preclinical experimental study | Mixed | CBD had a minor effect on alcohol consumption but reduced positive emotional states, while CBN and THCV reduced alcohol intake and preference with mild sedation and no distress. | |
| Cannabidiol Mitigates Ketamine-Induced Hyperlocomotion Via Allosteric Potentiation of Ventral Tegmental Glycine Receptor α1 Signaling. 2026 | experimental study | Supports | Cannabidiol blocks ketamine-induced hyperlocomotion by reversing glycine receptor dysfunction in the ventral tegmental area, with the GlyRα1 S296 residue being a key site for this interaction. | |
| Acute cannabidiol (CBD), tetrahydrocannabinol (THC) and their mixture (THC:CBD) exert differential effects on brain activity and blood flow in rats: A translational neuroimaging study. 2026 | randomized controlled trial | Mixed | CBD decreases brain functional connectivity without affecting blood flow, while THC increases connectivity and blood flow, and CBD moderates THC's effects when combined. | |
| Is Cannabidiol (CBD) a Non-Psychoactive Phytocannabinoid? 2026 | opinion piece | Supports | Argues that CBD should not be classified as a non-psychoactive phytocannabinoid, based on its demonstrated clinical effects in treating various psychiatric and neurological conditions. | |
| A Systematic Review of Therapeutic Potential of Illicit Drugs: A Narrative Overview of How Cannabinoids and Psychedelics Can be Used in Medicine 2025 | integrative literature review | Unclear | Argues that there is a lack of research on cannabis' medicinal use regarding treatments and diseases, its standardization, routes of administration, and doses. |
Pre-treatment with 600 mg oral CBD reduced THC-elicited paranoia and the odds of clinically significant positive psychotic symptoms, and mitigated THC-induced memory impairment.
randomized controlled trial Sample size: 48
CBD reduced arousal and dampened limbic brain activation during emotional processing, correlating with its anxiolytic trend.
double-blind, randomized, placebo-controlled crossover trial Sample size: 15
Argues that CBD shows anxiolytic and antipsychotic-like properties and may be a safe alternative treatment for schizophrenia.
review
CBD 300 mg, but not 100 mg or 900 mg, significantly reduced anxiety scores compared to placebo in the post-speech phase, showing an inverted U-shaped dose-response curve.
randomized controlled trial Sample size: 60
CBD showed no differences from placebo on any symptomatic or physiological variable.
randomized controlled trial Sample size: 16
Cannabidiol had no significant effects on psychotic symptoms, anxiety, intoxication, sedation, or brain activation during verbal learning.
randomized controlled trial Sample size: 15
Argues that cannabis and THC acutely affect neurocognitive systems, and that CBD may offset some of these acute effects, but heavy adolescent use is linked to increased risk of addiction and psychosis.
review
Functional neuroimaging suggests modulation of global and prefrontal metabolism during rest and after THC/marijuana administration, but evidence for major structural brain changes from cannabis is minimal.
systematic review
Cannabis containing equivalent concentrations of CBD and THC appears no less impairing than THC-dominant cannabis, and CBD may exacerbate THC-induced impairment in some circumstances.
randomized, double-blind, within-subjects crossover Sample size: 14
THC-only cannabis acutely reduced high-effort choices, while cannabis dependence was linked to impaired reward learning but not motivation; CBD did not significantly alter these effects.
randomized controlled trial Sample size: 17
THC generally did not affect task performance in heavy cannabis users, and CBD was not studied; alcohol potentiated THC effects on divided attention.
double-blind, placebo-controlled, three-way study Sample size: 21
CBD, but not THC, disrupted forward connectivity between the amygdala and anterior cingulate cortex during the neural response to fearful faces.
randomized controlled trial Sample size: 15
Varying concentrations of CBD did not change subjective, behavioral, or neurophysiological responses to smoked marijuana.
randomized controlled trial Sample size: 23
Acute doses of CBD were found to reduce anxiety both in animals and humans, without having an anxiogenic effect at higher doses.
systematic review
Single acute doses of CBD did not improve Stroop test performance in schizophrenic patients, and 600 mg was associated with worse performance compared to placebo or 300 mg.
randomized controlled trial Sample size: 28
CBD demonstrated potential antipsychotic, anxiolytic, and neuroprotective effects, but evidence for cannabis-based products in treating psychiatric disorders was limited, with modest short-term benefits but insufficient support for long-term efficacy.
systematic review and meta-analysis Sample size: 14
A 200 mg dose of synthetic CBD produced a 12.8% higher peak pleasant drug effect score than placebo, while lower doses (20, 50, 100 mg) showed no significant effect.
randomized controlled trial (crossover) Sample size: 70
The combination of CBD and sodium nitroprusside reduced hyperlocomotion and prevented novel object recognition deficits in both sexes in a ketamine rodent model of schizophrenia, with superior prophylactic effects in females.
animal study
A single CBD trial showed no clear benefit for PTSD symptom reduction.
systematic review and meta-analysis Sample size: 358
Acute THC and THC+CBD, but less so CBD alone, increase low-frequency EEG power and alter functional connectivity in CB1 receptor-rich brain regions of freely moving rats.
experimental study
CBD had a minor effect on alcohol consumption but reduced positive emotional states, while CBN and THCV reduced alcohol intake and preference with mild sedation and no distress.
preclinical experimental study
Cannabidiol blocks ketamine-induced hyperlocomotion by reversing glycine receptor dysfunction in the ventral tegmental area, with the GlyRα1 S296 residue being a key site for this interaction.
experimental study
CBD decreases brain functional connectivity without affecting blood flow, while THC increases connectivity and blood flow, and CBD moderates THC's effects when combined.
randomized controlled trial
Argues that CBD should not be classified as a non-psychoactive phytocannabinoid, based on its demonstrated clinical effects in treating various psychiatric and neurological conditions.
opinion piece
Argues that there is a lack of research on cannabis' medicinal use regarding treatments and diseases, its standardization, routes of administration, and doses.
integrative literature review
This synthesis reads the 15 most-cited and 10 most recent studies whose primary subject is CBD, up to 25 in all. The most-cited set anchors the established evidence, and the recent set surfaces work that is too new to have gathered citations yet.
A study qualifies only when CBD or a known alias appears in its title or keywords, so broad reviews that mention it only in passing are left out. Each study is read from its abstract, strongest evidence first, and the summary reports the direction of the results along with any conflicts and gaps.
199 articles · 48 from the last two years · 29,644 participants across 94 studies reporting sample size
J Psychopharmacol August 5, 2026
CB1 receptor-enriched functional connectivity analysis revealed target-specific modulation by cannabidiol in early psychosis.
Archives of Psychiatry and Mental Health July 29, 2026 Diamond Onyekachi Okoroezi
Aim: This systematic review and meta-analysis examined the neuropsychiatric effects of cannabis, focusing on the contrasting roles of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). It evaluated their associations with psychiatric outcomes, assessed the therapeutic potential of cannabis-based products (CBPs), and identified evidence gaps relevant to clinical practice and mental health...
Journal of Psychopharmacology July 15, 2026 Lucy A Chester, François-Olivier Hebert, Pamela Lachance-Touchette et al.
BACKGROUND Cannabidiol (CBD) is widely consumed in low-dose products. However, evidence for its psychotropic effects at non-clinical doses is sparse and inconsistent. AIMS To characterise the acute behavioural effects of low-dose synthetic CBD in healthy volunteers. We hypothesised that 200 mg of CBD would produce a greater peak pleasant drug effect than a placebo. METHODS In a triple-blind,...
Brazilian Journal of Psychiatry June 16, 2026 Daniel B.a. Prado, Matheus T. Rossignoli, Rafael N. Ruggiero et al.
Objective: Current treatments for schizophrenia (SZ) are often not effective for all symptoms, with sex-dependent effects poorly understood. Cannabidiol (CBD) and sodium nitroprusside (SNP) have emerged as potential prophylactic options. We evaluated their efficacy in preventing positive, negative, and cognitive deficits in a ketamine (KET) rodent model of SZ in both sexes. Methods: Wistar rats...
Physiological research May 12, 2026 Marcel Bochin, Čestmír Vejmola, Vlastimil Koudelka et al.
Cannabinoids modulate brain network activity, yet the spatial organization and temporal evolution of their electrophysiological effects remain insufficiently characterized in animal models. Here, we investigated how acute oral administration of ?9-tetrahydrocannabinol (THC; 10 mg/kg), cannabidiol (CBD; 10 mg/kg), and their combination influences resting-state EEG dynamics in freely moving rats....
Alcohol and alcoholism (Oxford, Oxfordshire) March 17, 2026 Ieva Poceviciute, Martynas Arbaciauskas, Rokas Buisas et al.
Previous studies have demonstrated that the endocannabinoid system plays a significant role in the development of alcohol use disorder (AUD), and CB1 receptor antagonists/inverse agonists show promise as a novel AUD pharmacotherapy. However, these compounds failed in clinical trials due to the severe psychiatric side effects. Non-psychoactive phytocannabinoids may have a better safety profile...
Biological Psychiatry March 16, 2026 Xianglian Wang, Jing Xia, Heyi Luo et al.
Ketamine produces rapid antidepressant and antidepressant-like effects in both humans and animal models. However, its therapeutic benefits are tempered by psychoactive side effects, such as hyperlocomotion associated with enhanced dopaminergic activity in the ventral tegmental area (VTA). We tested the therapeutic effect of cannabidiol (CBD) on locomotor activity after systemic (30 mg/kg) or...
Journal of psychopharmacology (Oxford, England) March 1, 2026 Eilidh Macnicol, Michelle Kokkinou, Maria Elisa Serrano Navacerrada et al. 2 citations
Cannabis constituents, including Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), show distinct pharmacological profiles with therapeutic relevance for neurological and psychiatric conditions. THC exerts euphoric effects primarily via CB1 receptor activation, while CBD displays non-euphoric properties affecting various pathways. This study evaluated the effects of THC, CBD, and their...
Psychoactives February 3, 2026 Eliana Rodrigues
Interest in psychoactive substances, including psychedelics, is rapidly expanding in medical, academic, and other popular fields. Despite the classifications established within the psychopharmacological scientific community, certain plants, animals, and fungi, as well as the substances obtained from them, have been misclassified by both the media and academic circles. This opinion piece aims to...
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology November 1, 2025 Justin C Strickland, Hayleigh E Tilton, Noah M Patton et al.
Cannabis products premixed with caffeine are increasingly present in the United States marketplace. Despite emergence of this product class, no human laboratory data have directly evaluated the isolated impact of caffeine on Δ9-tetrahydrocannabinol (Δ9-THC) effects as well as additional impacts of other common co-administered cannabinoids. This double-blind, randomized, placebo-controlled,...
Not yet recruiting Phase 2/3 105 participants Johns Hopkins University
Not yet recruiting Phase 1/2 280 participants Leslie Lundahl
Recruiting Phase 1/2 120 participants Universidade do Sul de Santa Catarina
Enrolling by invitation 384 participants Santa Catarina Federal University
Recruiting Phase 1/2 500 participants Wayne State University