Trial reportTranslational psychiatry2018
Individual and combined effects of acute delta-9-tetrahydrocannabinol and cannabidiol on psychotomimetic symptoms and memory function.
Trial report in Translational psychiatry, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 65 papers, 7 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
65 citing papers in PubMed, 7 syntheses or guidelines pooled it, 138 citations in OpenAlex.
- Evidence-based consensus guidelines for the pharmacological management of substance dependence: Recommendations from the British Association for Psychopharmacology.Journal of psychopharmacology (Oxford, England) · 2026Guideline
- Does acute cannabidiol (CBD) use impair performance? A meta-analysis and comparison with placebo and delta-9-tetrahydrocannabinol (THC).Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2024Pooled it
- The Effectiveness and Safety of Cannabidiol in Non-seizure-related Indications: A Systematic Review of Published Randomized Clinical Trials.Pharmaceutical medicine · 2022Pooled it
- The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review.Frontiers in psychiatry · 2021Pooled it
- Oral Administration of Cannabis and Δ-9-tetrahydrocannabinol (THC) Preparations: A Systematic Review.Medicina (Kaunas, Lithuania) · 2020Pooled it
- Association of Ketamine With Psychiatric Symptoms and Implications for Its Therapeutic Use and for Understanding Schizophrenia: A Systematic Review and Meta-analysis.JAMA network open · 2020Pooled it
- Psychiatric symptoms caused by cannabis constituents: a systematic review and meta-analysis.The lancet. Psychiatry · 2020Pooled it
- Does cannabidiol reduce the adverse effects of cannabis in schizophrenia? A randomised, double-blind, cross-over trial.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2025Trial
- Acute effects of cannabigerol on anxiety, stress, and mood: a double-blind, placebo-controlled, crossover, field trial.Scientific reports · 2024Trial
- The acute effects of cannabis with and without cannabidiol in adults and adolescents: A randomised, double-blind, placebo-controlled, crossover experiment.Addiction (Abingdon, England) · 2023Trial
- Does cannabidiol make cannabis safer? A randomised, double-blind, cross-over trial of cannabis with four different CBD:THC ratios.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2023Trial
- Assessment of Orally Administered Δ9-Tetrahydrocannabinol When Coadministered With Cannabidiol on Δ9-Tetrahydrocannabinol Pharmacokinetics and Pharmacodynamics in Healthy Adults: A Randomized Clinical Trial.JAMA network open · 2023Trial
- Effect of four-week cannabidiol treatment on cognitive function: secondary outcomes from a randomised clinical trial for the treatment of cannabis use disorder.Psychopharmacology · 2023Trial
- A Randomized, Triple-Blind, Comparator-Controlled Parallel Study Investigating the Pharmacokinetics of Cannabidiol and Tetrahydrocannabinol in a Novel Delivery System, Solutech, in Association with Cannabis Use History.Cannabis and cannabinoid research · 2022Trial
- Acute effects of cannabinoids on symptoms of obsessive-compulsive disorder: A human laboratory study.Depression and anxiety · 2020Trial
- A randomised controlled trial of vaporised ΔEuropean archives of psychiatry and clinical neuroscience · 2019Trial
- Longitudinal neurocognitive trajectories in a large cohort of youth who use cannabis: combining self-report and toxicology.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2026Article
- Memory impairment and chronic high-dose Δ9-THC/cannabis exposure: a narrative review of molecular mechanisms underlying neurotoxic effects.Psychopharmacology · 2026Review
- Assessing the influence of CYP2C9 and CYP2C19 genotypes on the metabolism of CBD-cannabis after controlled single and repetitive consumption.International journal of legal medicine · 2026Article
- Cannabidiol dose modulates behavioral response to acute and repeated administration of Δ9-Tetrahydrocannabinol by strain and sex.bioRxiv : the preprint server for biology · 2026Article
5 more citing papers are in PubMed but not listed here.
Corrections and comments
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Authors and funding
6 authors at 2 institutions in 1 country.
Funding
Abstract
The main active ingredient in cannabis, delta-9-tetrahydrocannabinol (THC), can acutely induce psychotic symptoms and impair episodic and working memory. Another major constituent, cannabidiol (CBD), may attenuate these effects. This study aimed to determine the effects of THC and CBD, both alone and in combination on psychotic symptoms and memory function. A randomised, double-blind crossover design compared the effects of (i) placebo, (ii) THC 8 mg, (iii) CBD 16 mg and (iv) THC 8 mg + CBD 16 mg administered by inhalation through a vaporiser. Using an experimental medicine approach to predict treatment sensitivity, we selected 48 cannabis users from the community on the basis of (1) schizotypal personality questionnaire scores (low, high) and (2) frequency of cannabis use (light, heavy). The Brief Psychiatric Rating Scale (BPRS), Psychotomimetic States Inventory (PSI), immediate and delayed prose recall (episodic memory), 1- and 2-back (working memory) were assessed on each day. Results indicated that THC increased overall scores on the PSI, negative symptoms on BPRS, and robustly impaired episodic and working memory. Co-administration of CBD did not attenuate these effects. CBD alone reduced PSI scores in light users only. At a ratio of 2:1, CBD does not attenuate the acute psychotic and memory impairing effects of vaporised THC. Frequent cannabis users may show a blunted anti- psychotic response to CBD, which is of concern due to the high rates of cannabis use disorders in patients with schizophrenia.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.