Related Experiment Video
Updated: Sep 10, 2025
Administration of Δ9-Tetrahydrocannabinol (THC) in Adolescent and Adult Mice
Published on: August 1, 2025
High-Concentration Delta-9-Tetrahydrocannabinol Cannabis Products and Mental Health Outcomes : A Systematic Review
Thanitsara Rittiphairoj1, Louis Leslie2, Jean-Pierre Oberste2
1Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (T.R.).
Background:
Rapid changes in the legalized cannabis market have led to the predominance of high-concentration delta-9-tetrahydrocannabinol (THC) cannabis products.
Purpose:
To systematically review associations of high-concentration THC cannabis products with mental health outcomes.
Data Sources:
Ovid MEDLINE through May 2025; EMBASE, Allied and Complementary Medicine Database, Cochrane Library, Database of Abstracts of Reviews of Effects, CINAHL, and Toxicology Literature Online through August 2024.
Study Selection:
Two reviewers independently selected studies with high-concentration THC defined as greater than 5 mg or greater than 10% THC per serving or labeled as "high-potency concentrate," "shatter," or "dab."
Data Extraction:
Outcomes included anxiety, depression, psychosis or schizophrenia, and cannabis use disorder (CUD). Results were categorized by association direction and by study characteristics. Therapeutic studies were defined by use of cannabis to treat medical conditions or symptoms.
Data Synthesis:
Ninety-nine studies (221 097 participants) were included: randomized trials (42%), observational studies (47%), and other interventional study designs (11%); more than 95% had moderate or high risk of bias. In studies not testing for therapeutic effects, high-concentration THC products showed consistent unfavorable associations with psychosis or schizophrenia (70%) and CUD (75%). No therapeutic studies reported favorable results for psychosis or schizophrenia. For anxiety and depression, 53% and 41% of nontherapeutic studies, respectively, reported unfavorable associations, especially among healthy populations. Among therapeutic studies, nearly half found benefits for anxiety (47%) and depression (48%), although some also found unfavorable associations (24% and 30%, respectively).
Limitation:
Moderate and high risk of bias of individual studies and limited evaluation of contemporary products.
Conclusion:
High-concentration THC products are associated with unfavorable mental health outcomes, particularly for psychosis or schizophrenia and CUD. There was some low-quality evidence, inconsistent by population, for therapeutic benefits for anxiety and depression.
Primary Funding Source:
Colorado General Assembly, House Bill 21-1317.
Related Concept Videos
01:24CNS Stimulants: Cocaine, Amphetamines and Cannabinoids
01:27Hallucinogens and Psychedelics
Marijuana, derived from the dried leaves and flowers of the hemp plant, contains...
01:21Chemotherapy-Induced Nausea and Vomiting: Cannabinoids
Two synthetic agonists of THC,...
01:30Stress and Mental Health
Individuals with depression often experience challenges in both their personal and professional...
01:06Altered States of Awareness
The ingestion of substances like stimulants or hallucinogens leads to chemical alterations in the brain...
01:29Stimulants
Cocaine can be administered via snorting, injection, or smoking. It primarily functions by blocking the reuptake of dopamine, resulting in a euphoric high characterized by an intense sensation of happiness and...