Cannabis Tolerance Research

Driving Performance and Cannabis Users' Perception of Safety: A Randomized Clinical Trial.

Marcotte, Thomas D · 2022

THC significantly impaired the Composite Drive Score at 30 minutes (d=0.59) and 1.5 hours (d=0.55), with borderline impairment at 3.5 hours (d=0.29) and no difference at 4.5 hours.

Are blood and oral fluid Δ9-tetrahydrocannabinol (THC) and metabolite concentrations related to impairment? A meta-regression analysis.

McCartney, Danielle · 2022

Higher blood THC, 11-OH-THC, oral fluid THC, and subjective intoxication were associated with greater impairment in occasional users, but correlations were negligible to weak (r = -0.08 to -0.43).

Psychosis-Relevant Effects of Intravenous Delta-9-Tetrahydrocannabinol: A Mega Analysis of Individual Participant-Data from Human Laboratory Studies.

Ganesh, Suhas · 2020

44.75% of THC infusions produced clinically meaningful positive psychosis symptoms.

Rapid Changes in CB1 Receptor Availability in Cannabis Dependent Males after Abstinence from Cannabis.

D'Souza, Deepak Cyril · 2016

Using high-resolution PET imaging, researchers measured CB1 receptor availability in 11 cannabis-dependent males and 19 matched healthy controls. At baseline (while using cannabis), dependent subjects showed 15% lower CB1 receptor availability across nearly all brain regions compared to controls, a large effect (Cohen's d = -1.11).

Pharmacokinetics and pharmacodynamics of cannabinoids.

Grotenhermen, Franjo · 2003

The review provided a detailed account of how THC and other cannabinoids are absorbed, distributed, metabolized, and eliminated.

Cannabis and the brain.

Iversen, Leslie · 2003

All known central effects of THC were mediated through CB1 receptors, with particularly high expression on GABAergic interneurons in the hippocampus, amygdala, and cerebral cortex.

Effects of acute THC challenge on behavior and neuroinflammation in HIV-1 Tg26 mice vary based on HIV status, chronic THC history, and sex.

Ravula, Havilah P · 2026

Chronic THC history (90 days) led to tolerance across behavioral measures, reducing THC-induced hypothermia, pain relief, and sedation, especially in females.

Cannabis Perturbs Dynamic Brain States.

Lege, Katharina S · 2025

This neuroimaging trial used a sophisticated approach—dynamic functional connectivity analysis—to examine how vaporized cannabis affects brain network organization in real time.

A multi-site study examining the tobacco withdrawal trajectory in people with tobacco and cannabis co-use.

Rabin, Rachel A · 2025

Among 330 participants with verified tobacco abstinence from a cessation trial (55 cannabis co-users, 275 tobacco-only), cannabis co-users had significantly elevated withdrawal scores at week 1 (mean 9.3 vs 7.1, p < 0.01).

Chronic Δ9-tetrahydrocannabinol exposure during adolescence is associated with persistent behavioural tolerance in adult nonhuman primates.

Razavi, Yasaman · 2025

Nonhuman primates treated daily with THC during adolescence (6 months at low or high doses) and tested approximately one year later as adults showed persistent behavioral tolerance.

Cannabis tolerance reduces symptom relief.

Stith, Sarah S · 2025

Patients experienced a 0.5% decrease in symptom relief per subsequent session (p<0.001).

Effects of acute cannabis inhalation on reaction time, decision-making, and memory using a tablet-based application.

Brooks-Russell, Ashley · 2024

Occasional users showed significant decrements in reaction time and short-term memory after smoking cannabis.

Sex-specific mechanisms of tolerance for the cannabinoid agonists CP55,940 and delta-9-tetrahydrocannabinol (Δ9-THC).

Henderson-Redmond, Angela N · 2022

The S426A/S430A mutation, which blocks CB1 receptor desensitization via the GRK/beta-arrestin2 pathway, conferred partial resistance to THC tolerance in male mice but did not alter tolerance in female mice.

Cannabidiol enhances the antinociceptive effects of morphine and attenuates opioid-induced tolerance in the chronic constriction injury model.

Jesus, Carlos Henrique Alves · 2022

CBD (30 mg/kg) combined with a sub-effective dose of morphine (1 mg/kg) produced enhanced pain relief for both evoked and ongoing pain that neither drug achieved alone.

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.

Influence of cannabis use history on the impact of acute cannabis smoking on simulated driving performance during a distraction task.

Miller, Ryan · 2022

Occasional cannabis users (1-2 times/week) had significantly increased lane departure risk during distraction after acute cannabis use (OR=3.71, P=0.04).

Safety, Pharmacokinetics and Pharmacodynamics of Spectrum Red Softgels in Healthy Participants.

Peters, Erica N · 2022

All 65 adverse events were mild-to-moderate; none were serious.

Assessment of dependence potential and abuse liability of Δ8-tetrahydrocannabinol in mice.

Vanegas, S O · 2022

Delta-8-THC produced cannabimimetic effects (catalepsy, antinociception, hypothermia, immobility) at doses above 12.5 mg/kg, all blocked by the CB1 antagonist rimonabant.

Simulated driving performance among daily and occasional cannabis users.

Brooks-Russell, Ashley · 2021

Occasional users showed significant increases in lane weaving (SDLP) compared to non-users after smoking (p=0.02, effect size 0.64).

Cannabidiol-enriched oil in children and adults with treatment-resistant epilepsy-does tolerance exist?

Uliel-Sibony, Shimrit · 2021

Of 84 patients analyzed for tolerance (treated at least 3 months), 21 (25%) developed tolerance after a mean of 7.3 months.

Is the Urine Cannabinoid Level Measured via a Commercial Point-of-Care Semiquantitative Immunoassay a Cannabis Withdrawal Syndrome Severity Predictor?

Claus, Benedikt Bernd · 2020

Urinary THC-COOH levels significantly correlated with Marijuana Withdrawal Checklist scores across the 24-day study (r = 0.248, p < 0.001).

"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.

Varenicline and nabilone in tobacco and cannabis co-users: effects on tobacco abstinence, withdrawal and a laboratory model of cannabis relapse.

Herrmann, Evan S · 2019

Varenicline doubled cotinine-verified tobacco abstinence (46% vs 24%) and reduced mood disturbance and cigarette craving.

Previous cannabis exposure modulates the acute effects of delta-9-tetrahydrocannabinol on attentional salience and fear processing.

Colizzi, Marco · 2018

Twenty-four healthy men participated in a double-blind THC challenge study, divided into 12 never-users (fewer than 5 lifetime joints) and 12 abstinent modest users (about 25 lifetime joints).

Modulation of acute effects of delta-9-tetrahydrocannabinol on psychotomimetic effects, cognition and brain function by previous cannabis exposure.

Colizzi, Marco · 2018

Using the same 24-participant THC challenge design, this companion study focused on cognitive processing and psychotomimetic effects.

Chronic Δ9-THC in Rhesus Monkeys: Effects on Cognitive Performance and Dopamine D2/D3 Receptor Availability.

John, William S · 2018

Six adult male rhesus monkeys were tested on cognitive tasks using touchscreen tests (CANTAB) before and during 12 weeks of daily THC (1.0-2.0 mg/kg). Acute THC impaired cognitive performance in a task-specific manner and reduced food-motivated responding and body temperature. During chronic treatment, THC produced persistent residual impairment only to working memory, measured 22 hours after each dose.

Slowly Signaling G Protein-Biased CB2 Cannabinoid Receptor Agonist LY2828360 Suppresses Neuropathic Pain with Sustained Efficacy and Attenuates Morphine Tolerance and Dependence.

Lin, Xiaoyan · 2018

Researchers characterized LY2828360, a CB2 cannabinoid receptor agonist that had previously failed in a clinical trial for osteoarthritis due to lack of efficacy. In vitro, LY2828360 was identified as a "G protein-biased" agonist: it activated G protein signaling but did not recruit arrestin, a pattern that may explain its sustained efficacy. In mice with chemotherapy-induced neuropathic pain (from paclitaxel), LY2828360 at 3 mg/kg/day for 12 days suppressed pain without developing tolerance.

The effect of high-dose dronabinol (oral THC) maintenance on cannabis self-administration.

Schlienz, Nicolas J · 2018

Chronic dronabinol dosing significantly reduced cannabis self-administration compared to placebo maintenance.

[18F]MK-9470 PET measurement of cannabinoid CB1 receptor availability in chronic cannabis users.

Ceccarini, Jenny · 2015

Researchers used a specialized PET imaging technique with the radioligand [18F]MK-9470 to measure CB1 receptor availability in 10 chronic cannabis users within the first week after their last use.

Smoked cannabis' psychomotor and neurocognitive effects in occasional and frequent smokers.

Desrosiers, Nathalie A · 2015

Fourteen frequent cannabis smokers (4+ times per week) and 11 occasional smokers (less than twice per week) smoked a single 6.8% THC cigarette in a controlled setting.

Plasma cannabinoid concentrations during dronabinol pharmacotherapy for cannabis dependence.

Milman, Garry · 2014

During placebo dosing periods, blood THC and its metabolites consistently decreased, supporting the withdrawal symptoms observed.

Subjective, cognitive and cardiovascular dose-effect profile of nabilone and dronabinol in marijuana smokers.

Bedi, Gillinder · 2013

Fourteen regular marijuana smokers completed a within-subjects comparison of nabilone (2, 4, 6, 8 mg), dronabinol (10, 20 mg), and placebo across seven sessions.

Analysis of tolerance and behavioral/physical dependence during chronic CB1 agonist treatment: effects of CB1 agonists, antagonists, and noncannabinoid drugs.

Desai, Rajeev I · 2013

Squirrel monkeys chronically treated with the potent CB1 agonist AM411 developed enormous tolerance to cannabinoid agonists, with up to 250-fold rightward shifts in potency.

Single doses of THC and cocaine decrease proficiency of impulse control in heavy cannabis users.

van Wel, J H P · 2013

In a study of 61 heavy cannabis users with cocaine use history, single doses of THC impaired both psychomotor function and impulse control accuracy.

The dose effects of short-term dronabinol (oral THC) maintenance in daily cannabis users.

Vandrey, Ryan · 2013

Thirteen daily cannabis smokers completed a within-subject crossover study receiving 0, 30, 60, and 120 mg dronabinol per day for five consecutive days each.

A placebo-controlled study to assess Standardized Field Sobriety Tests performance during alcohol and cannabis intoxication in heavy cannabis users and accuracy of point of collection testing devices for detecting THC in oral fluid.

Bosker, W M · 2012

Twenty heavy cannabis users participated in a placebo-controlled study where they smoked cannabis (400 micrograms/kg THC) with or without alcohol.

Medicinal Δ(9) -tetrahydrocannabinol (dronabinol) impairs on-the-road driving performance of occasional and heavy cannabis users but is not detected in Standard Field Sobriety Tests.

Bosker, Wendy M · 2012

Twenty-four participants (12 occasional users, 12 heavy users) received dronabinol (10 mg and 20 mg) or placebo in a crossover design, then drove on actual roads.

Evaluation of the safety and tolerability profile of Sativex: is it reassuring enough?

Wade, Derick · 2012

The reviewer evaluated published data on Sativex safety across several concern areas.

Marijuana dependence: not just smoke and mirrors.

Ramesh, Divya · 2011

The review compiled evidence that prolonged cannabis use produces genuine physical dependence in both humans and laboratory animals.

Abuse potential and psychoactive effects of δ-9-tetrahydrocannabinol and cannabidiol oromucosal spray (Sativex), a new cannabinoid medicine.

Robson, Philip · 2011

This review compiled safety data from all published Sativex clinical trials, including the integrated safety analysis for multiple sclerosis patients.

Neurocognitive performance during acute THC intoxication in heavy and occasional cannabis users.

Ramaekers, J G · 2009

Twelve occasional cannabis users and 12 heavy users smoked THC (500 mcg/kg) or placebo in a double-blind crossover design, with performance tested at intervals over 8 hours. Occasional users showed significant impairment on perceptual motor control (critical tracking), divided attention processing, and motor inhibition (stop signal task) after THC. Heavy users showed no impairment on any task except the stop signal task, where only stop reaction time increased, and only at high blood THC concentrations. Importantly, baseline (sober) performance comparisons between heavy and occasional users showed no persistent performance differences, arguing against residual THC impairment in heavy users. These results demonstrated that cannabis use history strongly determines the behavioral response to a given THC dose..

Cannabinoid tolerance and dependence: a review of studies in laboratory animals.

González, Sara · 2005

This extensive review compiled evidence from laboratory animal studies on cannabinoid tolerance and dependence.

Cardiovascular system effects of marijuana.

Jones, Reese T · 2002

Cannabis and THC increased heart rate, slightly increased blood pressure when lying down, and occasionally caused marked drops in blood pressure upon standing.

Clinical relevance of cannabis tolerance and dependence.

Jones, R T · 1981

Drawing on data from 120 research subjects, this review documented how the body adapts to repeated cannabis exposure and what happens when use stops. Tolerance developed to multiple effects: cardiovascular changes, lowered eye pressure, sleep disruption, mood changes, and behavioral effects.

Tolerance but No Spontaneous Withdrawal Following Repeated THC Injections in Male and Female Rats.

Hickey, Christa M · 2026

Researchers injected male and female rats with THC (3 mg/kg, twice daily) or vehicle for seven days, then abruptly stopped and monitored for withdrawal symptoms over five days using voluntary home cage wheel running — chosen as a sensitive, objective, and continuous measure. On day 1, THC profoundly decreased wheel running in both sexes compared to vehicle-treated rats — confirming the drug's acute sedating effects.

Does acute stress induced via cold water immersion increase blood THC concentrations in regular cannabis users?

McCartney, Danielle · 2025

Cold water immersion (10 minutes at 10 degrees C) produced a small but significant stress response (increased heart rate, blood pressure, decreased calmness) and increased plasma free fatty acids and glycerol.

Effects of sex and pre-exposure on Δ9-tetrahydrocannabinol (THC) vapor self-administration in rats.

Moore, Catherine F · 2025

Among 96 rats, both males and females voluntarily self-administered THC vapor over several months.

Acute effects of Δ9-tetrahydrocannabinol on computational measures of neurocognitive processes are related to recent cannabis use among adolescents and young adults.

Paige, K J · 2025

Overall, 7.5mg oral THC did not significantly alter cognitive performance compared to placebo.

Mechanisms of cannabinoid tolerance.

Piscura, Mary K · 2023

Anyone who uses cannabis regularly knows tolerance is real: the same dose produces weaker effects over time.

Gabapentin attenuates somatic signs of precipitated THC withdrawal in mice.

Eckard, M L · 2021

Gabapentin (10+ mg/kg) reduced paw tremors and head twitches during rimonabant-precipitated THC withdrawal.

Sex Differences in Tolerance to Delta-9-Tetrahydrocannabinol in Mice With Cisplatin-Evoked Chronic Neuropathic Pain.

Henderson-Redmond, Angela N · 2021

Female mice developed tolerance to the anti-allodynic (pain-relieving) effects of both 6 mg/kg and 10 mg/kg THC faster than males.

Persistent Exposure to Δ9-Tetrahydrocannabinol during Adolescence Does Not Affect Nociceptive Responding in Adult Mice.

Mabou Tagne, Alex · 2021

Adolescent mice receiving daily THC (5 mg/kg) from postnatal day 30-43 showed no significant differences from controls in formalin-induced pain behavior, chronic nerve injury pain responses, morphine antinociception, or morphine tolerance when tested at postnatal day 70.

Cannabinoid Antagonist Drug Discrimination in Nonhuman Primates.

Kangas, Brian D · 2020

Squirrel monkeys were trained to discriminate rimonabant (a CB1 antagonist/inverse agonist) from vehicle in a drug discrimination paradigm.

Effects of chronic nicotine exposure on Δ9-tetrahydrocannabinol-induced locomotor activity and neural activation in male and female adolescent and adult rats.

Miladinovic, T · 2020

In 112 rats, chronic nicotine followed by a washout period altered responses to THC challenge.

Sex, THC, and hormones: Effects on density and sensitivity of CB1 cannabinoid receptors in rats.

Farquhar, Charlotte E · 2019

Researchers gave male and female rats twice-daily THC injections for a week and then measured CB1 receptor density and function across four brain regions: cerebellum, hippocampus, prefrontal cortex, and striatum.

Cannabinoid CB2 Agonist AM1710 Differentially Suppresses Distinct Pathological Pain States and Attenuates Morphine Tolerance and Withdrawal.

Li, Ai-Ling · 2019

AM1710 produced sustained relief from paclitaxel-induced nerve pain without tolerance.

CB1 positive allosteric modulation attenuates Δ9-THC withdrawal and NSAID-induced gastric inflammation.

Trexler, K R · 2019

ZCZ011 (at 10 mg/kg and above) significantly reduced somatic withdrawal signs including head twitches and paw tremors in both precipitated and spontaneous THC withdrawal models.

Tolerance and dependence to Δ9-tetrahydrocannabinol in rhesus monkeys: Activity assessments.

Wilkerson, Jenny L · 2019

Chronic THC (1 mg/kg every 12 hours) produced dependence: rimonabant-precipitated withdrawal caused up to 20-fold increase in home-cage activity.

Rapid changes in cannabinoid 1 receptor availability in cannabis-dependent male subjects after abstinence from cannabis

D'Souza, Deepak Cyril · 2016

At baseline, cannabis-dependent men had lower CB1 receptor availability across most brain regions compared with matched non‑users.

Combined Treatment with Morphine and Δ9-Tetrahydrocannabinol in Rhesus Monkeys: Antinociceptive Tolerance and Withdrawal.

Gerak, L R · 2016

Combining opioids with cannabinoids is proposed as a way to enhance pain relief while potentially reducing opioid doses.

The impact of gonadal hormones on cannabinoid dependence.

Marusich, Julie A · 2015

Researchers removed the gonads of male and female rats and selectively replaced hormones to isolate their effects on THC dependence.

Phenotypic assessment of THC discriminative stimulus properties in fatty acid amide hydrolase knockout and wildtype mice.

Walentiny, D Matthew · 2015

Researchers compared mice lacking fatty acid amide hydrolase (FAAH), the enzyme primarily responsible for breaking down anandamide, with normal mice in a drug discrimination test using THC. Both groups learned to discriminate THC at similar rates and showed similar THC dose-response curves.

Evaluation of sex differences in cannabinoid dependence.

Marusich, Julie A · 2014

After 6.5 days of twice-daily THC administration (30 mg/kg), rats challenged with the CB1 antagonist rimonabant displayed a pronounced withdrawal syndrome spanning multiple domains.

Reversible and regionally selective downregulation of brain cannabinoid CB1 receptors in chronic daily cannabis smokers

Hirvonen, Jussi · 2012

Positron emission tomography showed lower availability of CB1 receptors in cortical regions among chronic daily cannabis smokers compared with non-using controls.

Apparent inverse relationship between cannabinoid agonist efficacy and tolerance/cross-tolerance produced by Δ⁹-tetrahydrocannabinol treatment in rhesus monkeys.

Hruba, Lenka · 2012

Rhesus monkeys trained to discriminate THC were given daily THC (1 mg/kg) for 3 or 14 days.

Antagonist-elicited cannabis withdrawal in humans.

Gorelick, David A · 2011

Ten male daily cannabis smokers received around-the-clock oral THC (40-120 mg/day increasing over 8 days) to standardize cannabis dependence in a closed research unit.

FAAH-/- mice display differential tolerance, dependence, and cannabinoid receptor adaptation after delta 9-tetrahydrocannabinol and anandamide administration.

Falenski, Katherine W · 2010

Repeated THC dosing shifted dose–response curves further to the right for classic cannabinoid effects in mice.

Rimonabant-induced Delta9-tetrahydrocannabinol withdrawal in rhesus monkeys: discriminative stimulus effects and other withdrawal signs.

Stewart, Jennifer L · 2010

Monkeys receiving chronic THC were trained to discriminate the cannabinoid antagonist rimonabant (which precipitates withdrawal) from vehicle.

Gz mediates the long-lasting desensitization of brain CB1 receptors and is essential for cross-tolerance with morphine.

Garzón, Javier · 2009

Injecting CB1 receptor agonists into the brain ventricles of mice produced dose-dependent pain relief, then a long-lasting drop in analgesic effect that persisted for more than 14 days.

Ligand-induced down-regulation of the cannabinoid 1 receptor is mediated by the G-protein-coupled receptor-associated sorting protein GASP1.

Martini, Lene · 2007

Agonist exposure led CB1 receptors to internalize, then get degraded rather than recycled back to the surface.

Influence of the anabolic-androgenic steroid nandrolone on cannabinoid dependence.

Célérier, Evelyne · 2006

Researchers examined whether the anabolic steroid nandrolone affects THC's pharmacological and behavioral effects in mice.

Effects of chronic Delta(9)-tetrahydrocannabinol treatment on hippocampal extracellular acetylcholine concentration and alternation performance in the T-maze.

Nava, F · 2001

Rats given chronic THC treatment (5 mg/kg twice daily for two weeks) continued to show reduced hippocampal acetylcholine levels and impaired T-maze performance without developing tolerance to either effect.

Cardiovascular effects of prolonged delta-9-tetrahydrocannabinol ingestion.

Benowitz, N L · 1975

Single doses of THC speed up heart rate and raise blood pressure.

Cannabis intoxication: effects of monetary incentive on performance, a controlled investigation of behavioural tolerance in moderate users of cannabis.

Casswell, S · 1975

Cannabis produced dose-related impairment on four out of five tasks testing short-term memory, goal-directed behavior, and reaction times.

Does tobacco dependence worsen cannabis withdrawal in people with and without schizophrenia-spectrum disorders?

Yeap, Zac J S · 2023

Cannabis withdrawal severity was worse in tobacco-dependent individuals compared to non-tobacco-dependent individuals.