Cannabis Potency Research

Adolescent cannabis use and psychological distress from 2013 to 2023: A population-based study in Ontario, Canada.

McDonald, André J · 2026

Distress rose from 10.7% to 27.4% while cannabis use declined from 23.1% to 17.6%.

Changes in clinical features and severity in patients presenting to European emergency departments with acute cannabis toxicity over the 10-year period from 2013 to 2022.

Miró, Òscar · 2026

Among 3,839 ED presentations for lone cannabis toxicity (2013-2022), the most common symptoms were anxiety (35%), agitation (22%), decreased alertness (21%), and vomiting (20%).

Youth Initiation of Cannabis Vaping Is Associated With State Cannabis Policy and E-Cigarette Use.

Vuolo, Mike · 2026

Youth in recreational cannabis states had 1.449 times the odds of initiating cannabis vaping compared to states where cannabis was illicit.

Accuracy of labeled THC potency across flower and concentrate cannabis products.

Giordano, Gregory · 2025

Labeling accuracy depended dramatically on product type: 96% of concentrates were within 15% of labeled THC versus only 56.7% of flower products.

The Individual and Interactive Effects of Alpha-Pinene and Delta-9-Tetrahydrocannabinol in Healthy Adults.

Kumar, Lakshmi · 2025

Alpha-pinene alone (15mg) had no effects vs.

High-Concentration Delta-9-Tetrahydrocannabinol Cannabis Products and Mental Health Outcomes : A Systematic Review.

Rittiphairoj, Thanitsara · 2025

In non-therapeutic studies, high-concentration THC showed unfavorable associations with psychosis/schizophrenia (70% of studies) and cannabis use disorder (75%).

Cannabidiol Increases Psychotropic Effects and Plasma Concentrations of Δ9-Tetrahydrocannabinol Without Improving Its Analgesic Properties.

Gorbenko, Andriy A · 2024

Co-administration of 450 mg CBD with 9 mg THC increased "Feeling High" by 60.5%, more than doubled THC blood levels (AUC ratio 2.18), and increased the active metabolite 11-OH-THC levels (AUC ratio 1.89).

Age-dependent association of cannabis use with risk of psychotic disorder.

McDonald, André J · 2024

Among 11,363 Ontario youth, cannabis use was associated with 11.2-fold increased psychosis risk during adolescence (12-19) but only non-significant 1.3-fold during young adulthood (20-33).

The contribution of cannabis use to the increased psychosis risk among minority ethnic groups in Europe.

Selten, J P · 2024

The odds ratio for psychotic disorder among non-Western minorities was 1.80, and adjusting for cannabis use frequency barely changed it (1.81).

Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis.

D'Souza, Deepak Cyril · 2022

Converging evidence supports that cannabis increases psychosis risk across a spectrum from transient states to chronic psychosis.

Task-independent acute effects of delta-9-tetrahydrocannabinol on human brain function and its relationship with cannabinoid receptor gene expression: A neuroimaging meta-regression analysis.

Gunasekera, Brandon · 2022

THC had neuromodulatory effects across a core network of brain regions central to many cognitive tasks and processes.

Cannabidiol (CBD) product contamination: Quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC) concentrations found in commercially available CBD products.

Johnson, Erin · 2022

THC was detected above the quantification limit in 52 of 80 unregulated CBD products (65%).

Label accuracy of unregulated cannabidiol (CBD) products: measured concentration vs. label claim.

Johnson, Erin · 2022

Of 80 products, 37 (46%) contained CBD concentrations more than 10% different from label claims.

A Comprehensive Review of Cannabis Potency in the United States in the Last Decade.

ElSohly, Mahmoud A · 2021

This third installment from the University of Mississippi's Potency Monitoring Program extended the dataset through 2019, adding 14,234 samples to the two previous reports (RTHC-00039 covering 1995-2014 and RTHC-00049 covering 2008-2017). THC continued its upward trajectory, reaching 14.88% in 2018 before a slight dip to 13.88% in 2019.

Annual incidence of cannabis-induced psychosis, other substance-induced psychoses and dually diagnosed schizophrenia and cannabis use disorder in Denmark from 1994 to 2016.

Hjorthøj, Carsten · 2021

Cannabis-induced psychosis incidence more than doubled from 2.8 per 100,000 in 2006 to 6.1 per 100,000 in 2016.

Blood and Oral Fluid Cannabinoid Profiles of Frequent and Occasional Cannabis Smokers.

Hoffman, Melissa A · 2021

Frequent users had higher residual blood THC and were more likely to test positive before even smoking.

Daily use of high-potency cannabis is associated with more positive symptoms in first-episode psychosis patients: the EU-GEI case-control study.

Quattrone, Diego · 2021

In patients, daily high-potency cannabis use was associated with the highest positive symptom scores (B=0.35, 95% CI 0.14-0.56) in a dose-response pattern.

Vitamin E Acetate in Bronchoalveolar-Lavage Fluid Associated with EVALI.

Blount, Benjamin C · 2020

Vitamin E acetate was detected in bronchoalveolar lavage fluid from 48 of 51 EVALI patients (94%) across 16 states but was absent in all 99 healthy comparators.

The influence of risk factors on the onset and outcome of psychosis: What we learned from the GAP study.

Murray, R M · 2020

In 410 first-episode psychosis patients and 370 controls in South London, approximately 25% of new psychosis cases were attributable to high-potency cannabis use.

Predictors of marijuana vaping onset and escalation among young adults.

Pokhrel, Pallav · 2020

Among 2,327 young adults followed for one year, dual cigarette/e-cigarette use at baseline was the strongest predictor of marijuana vaping initiation among non-marijuana users.

Pharmacodynamic dose effects of oral cannabis ingestion in healthy adults who infrequently use cannabis.

Schlienz, Nicolas J · 2020

In a placebo-controlled study with 17 infrequent cannabis users, 10 mg THC produced discriminable subjective effects and elevated heart rate but did not impair cognition.

Pharmacokinetics of Cannabis Brownies: A Controlled Examination of Δ9-Tetrahydrocannabinol and Metabolites in Blood and Oral Fluid of Healthy Adult Males and Females.

Spindle, Tory R · 2020

After consuming cannabis brownies (0, 10, 25, or 50 mg THC), blood THC and 11-OH-THC peaked at 1.5-2 hours and returned to baseline within 8 hours.

A randomised controlled trial of vaporised Δ9-tetrahydrocannabinol and cannabidiol alone and in combination in frequent and infrequent cannabis users: acute intoxication effects.

Solowij, Nadia · 2019

CBD alone (400 mg) showed some intoxicating properties vs.

Variation in cannabis potency and prices in a newly legal market: evidence from 30 million cannabis sales in Washington state.

Smart, Rosanna · 2017

Analyzing Washington State's cannabis traceability data from July 2014 to September 2016 (over 44 million purchases), the study revealed several market trends. Traditional cannabis flower still dominated at 66.6% of spending, but extracts for inhalation (concentrates) grew by 145.8% in market share, reaching 21.2% of sales.

Pharmacokinetic Profile of Oral Cannabis in Humans: Blood and Oral Fluid Disposition and Relation to Pharmacodynamic Outcomes.

Vandrey, Ryan · 2017

Six healthy adults per dose received cannabis brownies containing 10, 25, or 50 mg THC, with specimens collected for 9 days. Blood THC concentrations were remarkably low: mean peak levels were only 1, 3.5, and 3.3 ng/mL for the three doses, far lower than levels seen after smoking.

Free and Glucuronide Whole Blood Cannabinoids' Pharmacokinetics after Controlled Smoked, Vaporized, and Oral Cannabis Administration in Frequent and Occasional Cannabis Users: Identification of Recent Cannabis Intake.

Newmeyer, Matthew N · 2016

Researchers gave the same dose of cannabis to both frequent and occasional users through three routes: smoking, vaporizing, and eating.

Potency trends of delta9-THC and other cannabinoids in confiscated marijuana from 1980-1997.

ElSohly, M A · 2000

Researchers analyzed 35,312 cannabis preparations confiscated in the United States between 1980 and 1997, categorizing them as marijuana, sinsemilla, hashish, hash oil, Thai sticks, or ditchweed. More than 82% of confiscated samples were marijuana in every year.

Cannabis use measurement: Identifying the optimal metric for broad research applications.

Skrzynski, Carillon J · 2026

The Cannabis Quantity and Frequency Scale (CQFS) total times/day metric was a better predictor of the long-term THC metabolite (THC-COOH, R-squared 0.30 vs 0.27) while the Timeline Follow Back (TLFB) days/month metric was better at predicting acute blood THC levels (R-squared 0.24 vs 0.21)..

Outsmarting generic legislation: 4 years into the cat-and-mouse game of the synthetic cannabinoid receptor agonist market since the Chinese ban in 2021.

Deventer, Marie H · 2025

Ban-evading strategies included: alternative core structures (oxoindolins, oxopyridone, benzoate), linker replacement (acetamide instead of carboxamide), positional switching on conventional cores, adding or removing substituents (bromination, tail-less compounds), and a do-it-yourself synthesis approach where users convert legal tail-less precursors into banned potent SCRAs..

High potency cannabis flower use is associated with heavier consumption and risk for cannabis use disorder among young adults in California, United States.

Dunbar, Michael S · 2025

Each one-point increase in perceived THC potency was associated with 3.33 more use days per month, 0.13 more grams consumed per day, and 1.21 higher CUDIT-R (cannabis use disorder) scores.

The Pharmacokinetics and Pharmacodynamics of a Hemp-Derived "Full-Spectrum" Oral Cannabinoid Product with a 1:1 Ratio of Cannabidiol to Cannabidiolic Acid and Delta-9-Tetrahydrocannabinol to Delta-9-Tetrahydrocannabinolic Acid: A Double-Blind, Placebo-Controlled, Within-Subjects Human Laboratory Study.

Elder, Harrison J · 2025

CBDA and THCA achieved 19-25 times higher peak blood concentrations and reached peak levels up to twice as fast compared to CBD and THC.

Investigation of the toxic dose of ingested delta-8 tetrahydrocannabinol among young children.

Garay, Ryan S · 2025

Among 232 cases of young children who ingested delta-8 THC, those who consumed doses in the top quartile (above 17 mg/kg) had 3.4 times greater odds of severe toxicity and 5 times greater odds of prolonged toxicity.

Cannabis consumption patterns, adverse events, and cannabis risk beliefs: A latent profile analysis in WA State.

Garrett, Sharon B · 2025

Six user profiles ranged from weekly flower-only users to daily concentrate users.

A content analysis of cannabis edible product characteristics, packaging features, and online promotions.

Han, Bing · 2025

Among 2,282 cannabis edible products from US online dispensaries, over half were gummies and 80%+ contained at least 100 mg total THC.

Impact of Delta-8-THC warning labels on perceived intoxication, harm, and susceptibility among adolescents.

Harlow, Alyssa F · 2025

Among 3,647 Southern California adolescents, those shown delta-8-THC products with larger warning labels (vs.

Individual application patterns of Cannabis-based Medicines in Germany - Descriptive evaluation of a patient survey and discussion from a forensic perspective.

Hundertmark, Marica · 2025

Among 1,030 German medical cannabis patients, 89.9% used cannabis flowers.

Minor Cannabinoid Profile of Unregulated Cannabidiol Products.

Johnson, Erin · 2025

Among 80 over-the-counter CBD products, the most frequently detected minor cannabinoids were CBDV (100%), CBG (77%), CBC (72%), CBN (67%), CBL (67%), and CBDA (51%).

Legalization of Smokable Medical Cannabis and Changes in the Dispensed Amount of Δ-9 Tetrahydrocannabinol Per Patient.

Jugl, Sebastian · 2025

Legalizing smokable medical cannabis in Florida (SB182, March 2019) was associated with a 42.18% increase in mean weekly dispensed THC per patient (138.45 mg increase, 95% CI: 102.69-174.20) assuming 20% THC concentration.

High-Potency Cannabis Use and Health: A Systematic Review of Observational and Experimental Studies.

Lake, Stephanie · 2025

Of 42 eligible studies, most addressed mental health, problematic cannabis use, and other substance use.

Growing practices and the use of potentially harmful chemical additives from a web survey of mainly small-scale cannabis growers in 18 countries.

Lenton, Simon · 2025

In the 2020-21 survey, 26% of cannabis growers reported using chemicals.

Age Differences in Cannabis Consumption Patterns and in Associations Between Delta-9-Tetrahydrocannabinol Intake and Cannabis Use Disorders Among Adults with Daily Use.

Livne, Ofir · 2025

Over 70% of daily users across all ages used cannabis for both medical and recreational reasons.

Cannabis in the wild: Analysis of street cannabis and cannabinoid composition in Australia.

Lorenzetti, Valentina · 2025

One gram of Australian street cannabis contained an average of 34.8 mg THC (about 7 standard THC units) and 12% total THC with only 0.3% total CBD.

Cannabis Use Characteristics and Reasons for Product Choices Among Patients Accessing Treatment for Substance Use Disorders: A Mixed-Methods Study.

Matheson, Justin · 2025

89% of current cannabis users smoked dried flower for non-medical purposes.

Stimulant and medicinal cannabis prescribing in patients referred to an early psychosis service in Queensland: A brief report.

McArdle, Peter · 2025

Before referral, 3.2% of patients were prescribed medicinal cannabis; after psychosis, this rose to 6.8%.

Cannabis products and trends in a cohort of young adults: The VapeScan longitudinal study.

McGraw, Katlyn E · 2025

At Visit 2, 58.9% of participants reported cannabis use.

Association of Endothelial Dysfunction With Chronic Marijuana Smoking and THC-Edible Use.

Mohammadi, Leila · 2025

Among 55 participants, cannabis smokers had FMD of 6.0% and THC-edible users had 4.6%, both significantly lower than non-users at 10.4%.

Cannabis concentrate vaping chemistry.

Munger, Kaelas R · 2025

Vaping cannabis concentrates (50%+ cannabinoid products) produces harmful aerosol toxicants including isoprene, 3-methylcrotonaldehyde, and other volatile compounds.

The rising tide of drug-induced psychosis.

Murray, Robin M · 2025

Drug-induced psychosis from methamphetamine and cannabis has become more common over three decades.

Naturalistic investigation of cannabis strains varying in THC and CBD ratios and verbal recognition memory.

Paulich, Katie N · 2025

The idea that CBD might counteract THC's cognitive effects has been a popular hypothesis in cannabis research—and a selling point for balanced THC:CBD products.

Cannabis use and psychotic-like experiences: A systematic review of biological vulnerability, potency effects, and clinical trajectories.

Ricci, Valerio · 2025

Across 38 studies, four major risk factor categories emerged for psychotic-like experiences (PLEs) in non-clinical populations: biological vulnerabilities (metabolic profiles, genetics, neurobiology), substance use patterns (especially high-potency cannabis), socio-demographic factors (digital media, ethnic density, gender), and downstream consequences (suicidal behavior, cognitive impairment).

Product Characteristics, Warnings, and Marketing Appeals Conveyed on Delta-8 THC Product Packaging in the US and Canada.

Robichaud, Meagan O · 2025

Analysis of 140 delta-8 THC products from the US and Canada found that only 32.9% displayed any health warning, and warnings appeared on the front of packaging just 11.7% of the time.

The roles of cannabis potency and gender in cannabis dependence and anxiety in recent cannabis users with trauma exposure histories.

Snooks, T · 2025

Cannabis potency measured as relative THC proportion (THC%/[THC%+CBD%]) was significantly correlated with cannabis dependence (p=0.002) and anxiety (p=0.020).

A 10-year trend in cannabis potency (2013-2022) in different geographical regions of the United States of America.

ElSohly, Mahmoud A · 2024

This is the definitive U.S.

High-Potency Prenatal Cannabis Exposure and Birth Outcome Measures.

Kleinhans, Natalia M · 2024

Among 37 cannabis-exposed and 35 control newborns in otherwise low-risk pregnancies, cannabis-exposed newborns weighed less (38th vs 52nd percentile, p = 0.04) and were shorter (40th vs 55th percentile, p = 0.03).

Potency trends of cannabis in Jamaica during the period of 2014 to 2020.

Lindsay, Carole M · 2024

Median total THC increased significantly from 1.1% in 2014 to 10.2% in 2020 (p < 0.05).

Can the THC concentration predict the number of patients with cannabis-related diagnoses?

Manthey, Jakob · 2024

Using health insurance data from 2009-2021 and THC data from law enforcement, each one percentage point increase in median THC concentration predicted a higher proportion of cannabis users receiving an F12 diagnosis.

Cannabis-Derived Product Types, Flavors, and Compound Types From an E-Commerce Website.

Nali, Matthew C · 2024

Among 501,012 consumable product listings, multisystem routes of administration were most common (41%), followed by respiratory (37%) and digestive (20%).

Prevalence of ∆8-tetrahydrocannabinol carboxylic acid in workplace drug testing.

Vikingsson, Svante · 2023

Delta-8 THC has gone from obscure cannabinoid to widespread consumer product almost overnight, and this study shows it's already creating a significant presence in workplace drug testing.

The effects of acute Cannabis smoke or Δ9-THC injections on the trial-unique, nonmatching-to-location and five-choice serial reaction time tasks in male Long-Evans rats.

Barnard, Ilne L · 2022

High-THC cannabis smoke and THC injections impaired working memory on the TUNL task but had no effect on attention, impulsivity, or perseveration on the 5-CSRTT.

Effects of High-Potency Cannabis on Psychomotor Performance in Frequent Cannabis Users.

Karoly, Hollis C · 2022

Peak psychomotor impairment occurred immediately after cannabis use, with significant recovery by one hour post-use.

Characterization of Cannabis Products Purchased for Medical Use in New York State.

Kritikos, Alexandra F · 2022

This study examined medical cannabis product purchases in New York State from dispensaries operated by a single integrated manufacturer, characterizing what products patients actually selected in a tightly regulated market..

Edible marijuana products and potential risks for pediatric populations.

Lin, Allison · 2022

Edible marijuana products are indistinguishable from normal foods, lack the smell associated with smoked cannabis, have delayed onset that predisposes to overconsumption, and feature packaging intentionally similar to mainstream food brands, increasing accidental ingestion risk..

Fourth Generation of Synthetic Cannabinoid Receptor Agonists: A Review on the Latest Insights.

Malaca, Sara · 2022

Fourth-generation synthetic cannabinoid receptor agonists have increased CB1 receptor affinity and efficacy compared to previous generations, leading to more potent psychoactive effects and increased adverse reactions including psychosis, hallucinations, self-harm, tachycardia, and deaths..

Adulteration of low-delta-9-tetrahydrocannabinol products with synthetic cannabinoids: Results from drug checking services.

Monti, Manuela Carla · 2022

Of 94 samples, 50% contained up to three different synthetic cannabinoids, with MDMB-4en-PINACA most common.

Potency and Therapeutic THC and CBD Ratios: U.S. Cannabis Markets Overshoot.

Pennypacker, Sarah D · 2022

The ratio of THC to CBD in cannabis products matters enormously for therapeutic outcomes.

Urinary Excretion Profile of Cannabinoid Analytes Following Acute Administration of Oral and Vaporized Cannabis in Infrequent Cannabis Users.

Sholler, Dennis J · 2022

Using federal workplace drug-testing criteria (50 ng/mL screening, 15 ng/mL confirmation), urine specimens tested positive for THC-COOH in 97.6% of oral cannabis sessions versus 59.5% of vaporized sessions at active THC doses..

The phytochemical diversity of commercial Cannabis in the United States.

Smith, Christiana J · 2022

Distinct chemical phenotypes (chemotypes) were reliably present across commercial cannabis samples, but commercial labels (strain names, indica/sativa designations) did not consistently align with the observed chemical diversity, though certain labels showed biased associations with specific chemotypes..

Toxicological aspects of cannabinoid, pesticide and metal levels detected in light Cannabis inflorescences grown in Italy.

Amendola, G · 2021

Among 31 light cannabis inflorescence samples, THC was always below 0.5% and CBD ranged from 0.3-8.64%.

Mechanisms of cannabis impairment: Implications for modeling driving performance.

Burt, Thomas S · 2021

Nearly all driving impairment studies used inhaled cannabis at approximately 6% THC, far below the 20%+ THC flower and 60%+ THC concentrates now sold commercially.

Price and product variation in Washington's recreational cannabis market.

Davenport, Steven · 2021

This study analyzed the largest legal cannabis dataset available at the time: over 110 million retail transactions in Washington State from July 2014 to October 2017.

Communicating THC levels and 'dose' to consumers: Implications for product labelling and packaging of cannabis products in regulated markets.

Hammond, David · 2021

The review identified that consumers struggle with numeric THC information (mg vs.

The next generation of synthetic cannabinoids: Detection, activity, and potential toxicity of pent-4en and but-3en analogues including MDMB-4en-PINACA.

Krotulski, Alex J · 2021

MDMB-4en-PINACA had a potency of 2.47 nM (compared to JWH-018 at 25.3 nM, making it about 10 times more potent) with 239% efficacy.

The 'entourage effect' or 'hodge-podge hashish': the questionable rebranding, marketing, and expectations of cannabis polypharmacy.

Cogan, Peter S · 2020

The entourage effect concept, first proposed as a hypothesis in 1998, has been promoted as an established therapeutic principle despite lacking robust evidence.

Acute Effects of Cannabis Concentrate on Motor Control and Speed: Smartphone-Based Mobile Assessment.

Hitchcock, Leah N · 2020

Arm speed slowed immediately and remained impaired at 1 hour post-use.

"Residual blood THC levels in frequent cannabis users after over four hours of abstinence: A systematic review.".

Peng, Yuan Wei · 2020

Across 6 independent studies, frequent cannabis users showed blood THC above 2 ng/mL (or plasma THC above 3 ng/mL) after six days of abstinence in 5 studies.

Cannabinoid1 (CB-1) receptor antagonists: a molecular approach to treating acute cannabinoid overdose.

Skolnick, Phil · 2020

Cannabis legalization has dramatically increased ED visits and hospitalizations for acute cannabis overdose, with edibles and synthetic cannabinoids responsible for disproportionate share.

Cannabinoid toxicity in pediatrics.

Blohm, Eike · 2019

Young children hospitalized for cannabis toxicity are increasingly exposed to high-concentration products (edibles, resins, vaping fluid) containing extremely high cannabinoid levels, leading to sedation, respiratory depression, and other adverse effects.

New trends in cannabis potency in USA and Europe during the last decade (2008-2017).

Chandra, Suman · 2019

Picking up where ElSohly's earlier analysis left off, this study tracked another decade of cannabis potency data from the University of Mississippi's monitoring program.

The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study

Di Forti, Marta · 2019

This multicentre study across 11 sites in Europe and Brazil compared 901 people experiencing first-episode psychosis with 1,237 population controls.

Increasing potency and price of cannabis in Europe, 2006-16.

Freeman, Tom P · 2019

Using data from 28 EU member states plus Norway and Turkey, researchers tracked three variables for both cannabis resin and herbal cannabis: potency (% THC), price (euros per gram), and value (milligrams of THC per euro). Cannabis resin showed the most dramatic changes.

E-cigarette Use, or Vaping, Practices and Characteristics Among Persons with Associated Lung Injury - Utah, April-October 2019.

Lewis, Nathaniel · 2019

92% of interviewed patients reported using THC-containing products, 66% used nicotine products, and 60% used both.

Correlation of Breath and Blood Δ9-Tetrahydrocannabinol Concentrations and Release Kinetics Following Controlled Administration of Smoked Cannabis.

Lynch, Kara L · 2019

THC breath concentrations peaked at 15 minutes post-smoking (median 17.8 pg/L) and declined to <5% of peak in all participants by 3 hours.

Genetic tools weed out misconceptions of strain reliability in Cannabis sativa: implications for a budding industry.

Schwabe, Anna L · 2019

Using 10 microsatellite markers, researchers found two genetic groups, but these did not correspond to sativa/indica/hybrid labels.

The impacts of potency, warning messages, and price on preferences for Cannabis flower products.

Shi, Yuyan · 2019

Both users and non-users preferred higher CBD and lower prices.

A new ESI-LC/MS approach for comprehensive metabolic profiling of phytocannabinoids in Cannabis.

Berman, Paula · 2018

Researchers developed a new analytical method to profile 94 individual phytocannabinoids across 10 different subclasses in 36 of the most commonly prescribed medical cannabis strains in Israel.

Initiation of vaporizing cannabis: Individual and social network predictors in a longitudinal study of young adults.

Cassidy, Rachel N · 2018

Researchers tracked 1,313 first-year college students using social network methods to understand the emerging trend of vaping cannabis.

Validity of oral fluid test for Delta-9-tetrahydrocannabinol in drivers using the 2013 National Roadside Survey Data.

Jin, Huiyan · 2018

Researchers compared oral fluid and blood THC test results from 4,596 drivers stopped during the 2013 National Roadside Survey. Overall, 8.9% tested positive for THC in oral fluid and 9.4% in blood. Using blood testing as the reference standard, oral fluid testing showed 79.4% sensitivity (correctly identifying positive cases) and 98.3% specificity (correctly identifying negative cases). However, oral fluid THC concentration was a poor predictor of actual blood THC levels.

Growing practices and the use of potentially harmful chemical additives among a sample of small-scale cannabis growers in three countries.

Lenton, Simon · 2018

Researchers surveyed 1,722 current and recent small-scale recreational cannabis growers across three countries about their growing practices. Overall, 44% reported using any chemical fertilizers, supplements, or insecticides. Logistic regression found that hydroponic growing was the only significant predictor of chemical use.

Prevalence and Sociodemographic Correlates of Adolescent Use and Polyuse of Combustible, Vaporized, and Edible Cannabis Products.

Peters, Erica N · 2018

Researchers surveyed 3,177 tenth-grade students (mean age 16.1, 54% girls) from 10 Los Angeles high schools. Ever-use prevalence: combustible (smoking) 31.3%, edible 21.3%, vaporized 10.5%.

Cannabinoid Hyperemesis Syndrome: Pathophysiology and Treatment in the Emergency Department.

Richards, John R · 2018

CHS may result from the endocannabinoid system being overwhelmed by chronic cannabis use, with acute episodes triggered by stress or fasting.

Cannabinoid hyperemesis syndrome: Review of the literature and of cases reported to the French addictovigilance network.

Schreck, Benoît · 2018

CHS mainly affects young male subjects who have smoked cannabis daily for several years.

Changes in cannabis potency over the last 2 decades (1995-2014): Analysis of current data in the United States

ElSohly, Mahmoud A. · 2016

Researchers analyzed 38,681 cannabis samples seized by the DEA over twenty years.

Nonsmoker Exposure to Secondhand Cannabis Smoke. III. Oral Fluid and Blood Drug Concentrations and Corresponding Subjective Effects.

Cone, Edward J · 2015

Six non-smokers sat alternately with six cannabis smokers in a sealed chamber for one hour across three sessions.

Non-smoker exposure to secondhand cannabis smoke. I. Urine screening and confirmation results.

Cone, Edward J · 2015

Six non-smokers were exposed to secondhand cannabis smoke in a sealed chamber with six smokers for one hour across three sessions.

Non-smoker exposure to secondhand cannabis smoke II: Effect of room ventilation on the physiological, subjective, and behavioral/cognitive effects.

Herrmann, Evan S · 2015

Non-cannabis-using individuals were exposed to secondhand smoke from six people smoking 11.3% THC cannabis in a sealed chamber for one hour under two conditions: unventilated and ventilated (11 air exchanges per hour). Unventilated exposure produced detectable THC in blood and urine, minor heart rate increases, mild-to-moderate self-reported sedation, and impaired performance on a cognitive task (digit symbol substitution).

Analysis of cannabis seizures in NSW, Australia: cannabis potency and cannabinoid profile.

Swift, Wendy · 2013

Researchers analyzed 206 cannabis samples confiscated from recreational users under the New South Wales Cannabis Cautioning scheme, along with 26 samples from known indoor or outdoor cultivation sites.

Has the intake of THC by cannabis users changed over the last decade? Evidence of increased exposure by analysis of blood THC concentrations in impaired drivers.

Vindenes, Vigdis · 2013

Researchers analyzed THC blood concentrations from 1,747 drivers apprehended in Norway on suspicion of driving under the influence of cannabis between 2000 and 2010.

Monitoring of herbal mixtures potentially containing synthetic cannabinoids as psychoactive compounds.

Dresen, Sebastian · 2010

Researchers analyzed over 140 samples of "herbal incense" products (marketed as legal cannabis alternatives) between June 2008 and September 2009. Initially, products contained CP-47,497-C8 and JWH-018.

Enhancement drugs: are there limits to what we should enhance and why?

Hesse, Morten · 2010

This commentary made two specific harm-reduction proposals: For alcohol: adding dissolved oxygen could reduce accident risk and liver damage. For cannabis: strong evidence indicated that reducing THC content and increasing CBD content could reduce the risk of psychosis and addiction associated with cannabis use. The author argued that public health interventions should focus on reducing concrete harms rather than making moral judgments about which human experiences should or should not be enhanced through substance use. The central proposition was that responsible regulation should not be limited to preventing or reducing use, but should include strategies to reduce the burden of illness associated with substance use..

Cognitive and psychomotor effects in males after smoking a combination of tobacco and cannabis containing up to 69 mg delta-9-tetrahydrocannabinol (THC).

Hunault, Claudine C · 2009

Twenty-four non-daily male cannabis users smoked cannabis cigarettes containing 0, 29.3, 49.1, or 69.4 mg THC in a four-way crossover design. Response time slowed linearly across all cognitive tasks (simple reaction time, visual-spatial attention, sustained attention, divided attention, and short-term memory) as THC dose increased.

Neurophysiological and subjective profile of marijuana with varying concentrations of cannabinoids.

Ilan, A B · 2005

Twenty-three healthy marijuana users (12 men, 11 women) participated in four sessions where they smoked marijuana cigarettes under blinded conditions.

Vaping Δ9-tetrahydrocannabinol (Δ9-THC) in liquid forms: pharmacokinetics, pharmacodynamics, and regulatory implications.

Block, Ashleigh C · 2026

No human PK/PD studies exist for vaped liquid THC despite growing prevalence; analysis suggests these products may be more potent than smoked cannabis but consumer behavior may modulate delivery, creating an unpredictable risk profile..

Semi-synthetic cannabinoids: Recent developments, analytical challenges and strategic responses.

Christie, Rachel · 2026

Since hexahydrocannabinol (HHC) first appeared in Europe in late 2022, the semi-synthetic cannabinoid market has expanded rapidly.

Psychotic Risk Associated With Cannabinoid Use: A Case Report of Ekbom-Like Delusional Infestation.

Pao Trigo, Miguel · 2026

A man with decades of daily cannabis use presented with persistent pruritus, tactile hallucinations, and a fixed belief that parasites infested his skin.

Evaluation of THC-induced neurotoxicity via oxidative stress in undifferentiated SH-SY5Y cells.

Sanz-Pérez, A · 2026

THC at 73.75 and 150 ng/mL significantly reduced cell viability (to 76.5% and 64.6% at 48 hours) and caused morphological changes.

Behavioral pharmacology of novel synthetic indazole, indole, and benzimidazole cannabinoids in rodents.

Shetty, Ritu A · 2026

The DEA identified 11 synthetic cannabinoids of concern, and researchers tested each one in rodent models for two key properties: how strongly they suppressed movement (locomotor depression) and whether rats trained to recognize THC also recognized these compounds (drug discrimination). In locomotor tests, most of the 11 compounds were more potent than THC (which had an ED50 of 3.3 mg/kg).

Fast and reliable in vitro activity-based detection of synthetic cannabinoid receptor agonists in e-liquids.

Timmerman, Axelle · 2026

Researchers applied a cell-based activity screening method (CB1/β-arrestin2 recruitment assay using the NanoBiT principle) to detect synthetic cannabinoid receptor agonists (SCRAs) in e-liquids — the first time this approach was used on a real patient case. When applied to an e-liquid from an intoxicated patient, the assay demonstrated strong cannabinoid activity, confirming the presence of SCRAs.

A Qualitative Study of How Teens in Washington State Make Sense of Cannabis Edibles Warning Labels and Packaging.

Willoughby, Jessica Fitts · 2026

Teens misinterpreted warning labels on cannabis edibles and felt warnings were hidden or unnoticeable.

Identification of Three Novel Tetrahydrocannabinol Analogs in the European Market.

Dadiotis, Evangelos · 2025

Products marketed under invented cannabinoid names contained novel THC analogs that have never been found in cannabis plants and lack any toxicological data.

Synthetic cannabinoids in Mayotte over a year in time and space: an example of high-frequency evolution of market.

Devault, Damien Alain · 2025

Thirteen different synthetic cannabinoid receptor agonists were identified across 195 samples (187 cigarettes, 8 powders).

Adolescents and cannabis in the 21st century: Current Problems in Pediatric and Adolescent Health Care.

Itriyeva, Khalida · 2025

This comprehensive review covers three decades of adolescent cannabis trends in the United States, and the picture it paints is more complicated than either "legalization is harmless" or "legalization is catastrophic" narratives suggest. Teenage use rates have remained remarkably stable despite legalization.

Characterizing cannabis use among adolescents seeking treatment for their substance use.

Kumar, Prianka · 2025

Most adolescents used multiple cannabis products.

Bridging THC Knowledge Gaps for Safer Roads: A Call for Action.

Li, Peizhi · 2025

This commentary cuts to the heart of a policy problem: states are setting cannabis driving laws without the science to back them up.

Commercial Cannabis Product Testing: Fidelity to Labels and Regulations.

Limbacher, Sarah · 2025

Overall, label values were significantly higher than tested values for flower and edible products (p<0.001), but not for concentrates (p=0.85).

Associations between cannabis risk perceptions and Delta-8 THC use among young adults.

LoParco, C R · 2025

Past-year Delta-9 THC use was associated with 20 times the odds of Delta-8 use.

What Influences Cannabis Purchasing Decisions? Perspectives from Cannabis Retail Employees and Customers in Washington State.

Okey, Sarah A · 2025

Cannabis retail employees rated THC concentration as less important and terpene profiles, production methods, and product appearance as more important compared to non-employee customers.

Emerging Hemp-Derived Semi-Synthetic Cannabinoids, Absent Regulations: Patterns of Use and Adverse Effects Among a Sample of U.S. Cannabis Consumers.

Pabon, Elisa · 2025

Delta-8 THC (21.8%), THCP (24.4%), and Delta-10 THC (14.0%) were the most commonly used semi-synthetic cannabinoids.

Evaluating Delta-8-THC-Induced Psychosis: A Systematic Review.

Ralston, Megan Jayne · 2025

From 201 studies screened, 12 met criteria and 6 case reports involving 9 patients were reviewed.

A Thematic Text Analysis of Cannabis Edibles Brand Names.

Reboussin, Beth A · 2025

Among 1,344 cannabis edible products from 250 brands, five brand name themes emerged: cannabis culture (42%), product characteristics (30%), medicine/health (23%), environment/nature (20%), and identity/culture (14%).

A user-informed perspective of the toxicological data gap in India's cannabis landscape.

Riyaz, Muzafar · 2025

The author argues that clinical cannabis research using purified compounds fails to capture the realities of illicit markets where products like Ganja and Charas have unpredictable potency, pesticide contamination, and adulteration.

A Survey Study of Individuals Using Hexahydrocannabinol Cannabis Products: Use Patterns and Perceived Effects.

Ferretti, Morgan L · 2024

HHC users reported using approximately 10 days in the past month.

Delta-8 tetrahydrocannabinol: a scoping review and commentary

LoParco, Cassidy R. · 2023

Delta-8 THC exists in a remarkable regulatory gray zone.

Trends in Illicit Cannabis Potency based on the Analysis of Law Enforcement Seizures in the Southern Area of Rome.

Vernich, Francesca · 2023

The potency escalation in cannabis isn't just a North American phenomenon.

Analysis of Anti-Cancer and Anti-Inflammatory Properties of 25 High-THC Cannabis Extracts.

Li, Dongping · 2022

Anti-cancer efficacy ranged from 66% to 92% growth inhibition across 25 extracts.

Using ecological momentary assessment and a portable device to quantify standard tetrahydrocannabinol units for cannabis flower smoking.

Trull, Timothy J · 2022

One of the biggest problems in cannabis research is that 'a joint' can contain wildly different amounts of THC depending on the flower's potency and how much is used.

The failings of per se limits to detect cannabis-induced driving impairment: Results from a simulated driving study.

Arkell, Thomas R · 2021

At 30 minutes after vaporizing THC, 46% of participants who exceeded legal THC blood limits showed no measurable driving impairment.

Δ8-THC: Legal Status, Widespread Availability, and Safety Concerns.

Babalonis, Shanna · 2021

Delta-8 THC products are widely available without regulation despite being classified as Schedule I by the DEA.

Potential Adverse Drug Events with Tetrahydrocannabinol (THC) Due to Drug-Drug Interactions.

Brown, Joshua D · 2020

This review mapped out the pharmacological interactions between THC and other medications, revealing a more complex picture than most cannabis users — or their doctors — appreciate.

A Little Dab Will Do: A Case of Cannabis-Induced Psychosis.

Rossi, Garrett · 2020

A patient who had used marijuana since age 13 for anxiety without psychotic episodes developed severe paranoid delusions (being watched and followed), insomnia for two weeks, and hypervigilant behavior after switching to "dabbing" (concentrated cannabis with up to 80% THC).

Cannabis treatment in hospitalized patients using the SYQE inhaler: Results of a pilot open-label study.

Vulfsons, Simon · 2020

Daily cannabis consumption dropped from a median of 1,000 mg to 51 mg when using the SYQE Inhaler.

In vitro and in vivo pharmacological activity of minor cannabinoids isolated from Cannabis sativa.

Zagzoog, Ayat · 2020

THC, THCA, THCV, CBD, CBDA, CBDV, CBG, and CBC were tested for receptor binding, cAMP inhibition, beta-arrestin2 recruitment, and in vivo effects.

Cannabis knowledge and implications for health: Considerations regarding the legalization of non-medical cannabis.

Zamengo, Luca · 2020

This review synthesized what had been observed in jurisdictions that legalized recreational cannabis and found a consistent pattern: potency increased as commercial producers optimized for THC content, cannabis-related emergency department visits rose, and public perception of risk declined — particularly among young people. The authors argued that legalization frameworks had primarily focused on market economics — creating legal supply chains, diverting profits from illegal markets, and reducing prohibition costs — while underweighting health and safety considerations.

Hair cannabinoid concentrations in emergency patients with cannabis hyperemesis syndrome.

Albert, Khala · 2019

Hair cannabinoid concentrations were similar between cannabis hyperemesis patients (THC median 220 pg/mg), recreational user controls (150 pg/mg), and emergency department controls (270 pg/mg).

Terpenoids and Phytocannabinoids Co-Produced in Cannabis Sativa Strains Show Specific Interaction for Cell Cytotoxic Activity.

Namdar, Dvora · 2019

Specific terpenoid groups were statistically associated with THC-rich or CBD-rich strains.

Biphasic effects of THC in memory and cognition.

Calabrese, Edward J · 2018

The well-known cognitive impairment from THC — disrupted short-term memory, slower processing — turns out to be only half the story.

Composition and Use of Cannabis Extracts for Childhood Epilepsy in the Australian Community.

Suraev, A · 2018

There was high variability in cannabinoid content across extracts.

Acceptance of pharmaceutical cannabis substitution by cannabis using patients with schizophrenia.

van Amsterdam, Jan · 2018

Both substitute variants (low THC/no CBD and low THC/high CBD) were appreciated by patients.

Perceived harms and benefits of tobacco, marijuana, and electronic vaporizers among young adults in Colorado: implications for health education and research.

Popova, Lucy · 2017

Through 32 in-depth interviews with young adults aged 18-26 in Denver who used tobacco, marijuana, or vaporizers, researchers identified five dimensions these users applied when evaluating harms and benefits. Combustion: smoking anything was considered more harmful than non-combustible forms (edibles, vaporizers).

Cannabis sativa (Hemp) Seeds, Δ9-Tetrahydrocannabinol, and Potential Overdose.

Yang, Yi · 2017

Researchers tested three brands of consumer-grade hemp seeds using four different extraction methods to measure THC and CBD content.

Case Report of Intractable Vomiting and Abdominal Pain Related to Heavy Daily Cannabis Use.

Gammeter, William Bryce · 2016

An anxious, dehydrated teenager arrived at the emergency department with uncontrollable vomiting, weight loss, and abdominal pain.

"Those edibles hit hard": Exploration of Twitter data on cannabis edibles in the U.S.

Lamy, Francois R · 2016

Researchers collected over 100,000 tweets mentioning cannabis edibles between May and July 2015.

Dose-dependent effects of cannabis on the neural correlates of error monitoring in frequent cannabis users.

Kowal, Mikael A · 2015

Researchers used EEG to measure two brain signals related to error monitoring in frequent cannabis users: the error-related negativity (ERN), which reflects automatic error detection, and the error positivity (Pe), which reflects conscious error awareness. Participants who received a high dose (22mg THC) showed significantly reduced ERN compared to placebo, meaning their brains were less effective at automatically detecting mistakes.

Cannabis and creativity: highly potent cannabis impairs divergent thinking in regular cannabis users.

Kowal, Mikael A · 2015

Researchers tested whether cannabis enhances creativity by giving regular users either placebo, low-dose (5.5mg THC), or high-dose (22mg THC) vaporized cannabis, then measuring their performance on creativity tasks. Participants who received the high dose performed significantly worse on the Alternate Uses Task, a measure of divergent thinking (the ability to generate multiple creative solutions).

Isolation and Pharmacological Evaluation of Minor Cannabinoids from High-Potency Cannabis sativa.

Radwan, Mohamed M · 2015

Researchers isolated and characterized seven new naturally occurring cannabinoids from high-potency Cannabis sativa, all of which were hydroxylated (oxygen-containing) variants of known cannabinoids. When tested for binding to cannabinoid receptors, compound 3 (10-alpha-hydroxy-delta-8-THC) showed the highest affinity for CB1 receptors and produced the most potent cannabimimetic effects in mice (reduced movement, lowered body temperature, reduced pain sensitivity, and catalepsy).

Investigation of sex-dependent effects of cannabis in daily cannabis smokers

Cooper, Ziva D. · 2014

Women gave higher "Good" (p<=0.05) and "Take Again" (p<=0.05) ratings than men under active cannabis conditions in a pooled analysis of four double-blind studies, despite no sex differences in intoxication ratings ("High," "Stimulated") or cardiovascular response.

Benign and time-limited visual disturbances (flashbacks) in recent abstinent high-potency heavy cannabis smokers: a case series study.

Lerner, Arturo G · 2011

Eight patients seeking outpatient detoxification for cannabis dependence reported visual disturbances both during intoxication and persisting after they stopped using cannabis.

Tetrahydrocannabivarin (THCV) Dose Dependently Blocks or Substitutes for Tetrahydrocannabinol (THC) in a Drug Discrimination Task in Rats.

Kayir, Hakan · 2025

THCV produced an inverted U-shaped response curve in THC-trained rats.

Derivation of a health-based guidance value for Δ8-tetrahydrocannabinol (Δ8-THC) and its occurrence in food.

Knutsen, Helle Katrine · 2025

EFSA set a relative potency factor of 1 for delta-8-THC (equivalent to delta-9-THC) based on clinical data showing a potency ratio between 1 and 1.4.

The impact of schizophrenia genetic load and heavy cannabis use on the risk of psychotic disorder in the EU-GEI case-control and UK Biobank studies.

Austin-Zimmerman, Isabelle · 2024

In the EU-GEI study, daily use of high-potency cannabis had OR 5.09 (95% CI 3.08-8.43) for psychotic disorder even after adjusting for schizophrenia polygenic risk score (PRS).

Threaten, Distract, and Discredit: Cannabis Industry Rhetoric to Defeat Regulation of High-THC Cannabis Products in Washington State.

Carlini, Beatriz H · 2024

Three rhetorical strategies dominated industry opposition to high-THC regulation: threatening (economic harm, public health consequences, undermining voter will), distracting (introducing tangential topics), and discrediting (attacking the science or its advocates).

Identifying policy options to regulate high potency cannabis: A multiple stakeholder concept mapping study in Washington State, USA.

Carlini, Beatriz H · 2024

Community and professional stakeholders supported environmental policy changes like THC-based taxation, raising the minimum age for high-concentration products, and advertising restrictions.

Factors Associated with Delta-8 THC Retail Availability in Fort Worth, Texas, 2021-2022.

LoParco, C R · 2024

Delta-8 THC retail availability was 11% at the first time point and 9% at the second, showing no significant decline despite ongoing legal challenges.