Smoked cannabis significantly reduced MS spasticity and pain in a placebo-controlled trial ↗
Smoked cannabis significantly reduced MS spasticity and pain compared to placebo in 30 patients, but also impaired cognitive performance.
Research library — page 12
Browse more cannabis research, findings, methods, and limitations.
Brain scans predicted which heavy cannabis users would develop worse problems six months later ↗
Brain activity in cognitive control regions predicted which heavy cannabis users would develop worse problems over 6 months, beyond what craving alone predicted.
State of the art in treating cannabis dependence: what works, what does not, and what is needed ↗
Review finding combination therapies (motivational + cognitive-behavioral + incentives) most effective for cannabis dependence, though long-term abstinence remains below 20%.
Nurses face ethical dilemmas when patients with terminal illness use cannabis for quality of life ↗
Review of ethical challenges nurses face when terminally ill patients use cannabis for quality of life, navigating between patient care and legal restrictions.
How four lesser-known cannabinoids move through the body and brain in rats and mice ↗
Pharmacokinetic study showing four lesser-known cannabinoids (CBD, CBDV, THCV, CBG) all cross the blood-brain barrier, with CBD reducing OCD-like behavior in mice.
Brain activity patterns during psychosis overlap with cannabis effects in key regions ↗
Systematic review found first-episode psychosis and cannabis effects both increased anterior cingulate cortex activity, suggesting shared neural mechanisms.
Shared genetics explain the link between borderline personality and cannabis use, but not alcohol ↗
Twin study of 5,638 found the link between borderline personality and cannabis use is genetically driven, while the alcohol connection is environmental.
Heated versus unheated cannabis extracts produced very different drug levels in the body ↗
In 9 volunteers, unheated cannabis extract produced nearly double the CBD blood levels and different metabolic profiles compared to heated extract.
A serotonin gene variant influenced brain response to cannabis treatment in adolescents ↗
Preliminary study found a serotonin receptor gene variant influenced brain activation patterns after cannabis treatment in adolescents.
The economic cost of drug-related crime in Chile: cannabis was the least costly substance ↗
Analysis of Chile's drug-crime costs found cannabis accounted for only 18% of the $268 million burden, compared to 53% for cocaine base paste.
Synthetic cannabinoids JWH-018 and JWH-073 acted like THC in monkeys but wore off faster ↗
Synthetic cannabinoids JWH-018 and JWH-073 produced THC-like effects in monkeys but lasted only 1-2 hours versus THC's 4, potentially increasing addiction risk.
Adolescent cannabinoid exposure in mice caused lasting schizophrenia-like brain and behavior changes ↗
Adolescent but not adult cannabinoid exposure in mice produced lasting schizophrenia-like deficits, linked to reduced hippocampal mGluR5 and altered endocannabinoid metabolism.
CB1 blocker rimonabant raised cortisol levels in cannabis-dependent men, hinting at stress axis involvement ↗
In cannabis-dependent men, rimonabant blood levels correlated with cortisol increases, providing human evidence that CB1 receptors modulate the stress hormone system.
Clearing away the smoke: clinical evidence for medical marijuana with a prescribing guide ↗
Review of medical cannabis evidence supporting neuropathic pain and spasticity, with a practical physician algorithm for prescribing decisions.
Over 100 controlled clinical trials supported therapeutic potential of cannabinoids ↗
Review noting over 100 controlled trials since 1975 supporting cannabinoid therapeutics, with three approved medicines and manageable side effects.
Spice and K2: clinical effects, toxicity, and three cases of cannabis-dependent users switching to synthetics ↗
Review of Spice/K2 effects found anxiety and psychosis reports, while three cases showed cannabis-dependent users found synthetics relieved their withdrawal.
Cannabis impairs working memory through brain support cells, not neurons directly ↗
Landmark Cell paper showing cannabis impairs working memory through CB1 receptors on astrocytes (support cells), not on neurons directly.
Long-term cannabis users showed increased brain connectivity that may compensate for impairment ↗
Long-term cannabis users showed normal cognitive performance but increased brain connectivity between control and attention regions, suggesting neural compensation.
Female adolescent rats were more sensitive to THC withdrawal anxiety than males ↗
Female adolescent rats showed greater locomotor depression and anxiety during THC withdrawal compared to males across multiple doses.
Smoking cigarettes predicted new cannabis and alcohol disorders in teens with bipolar disorder ↗
In adolescents with new-onset bipolar disorder, cigarette smoking predicted development of cannabis and alcohol disorders, while quitting smoking did not worsen mood.
Two epilepsy patients had dramatic seizure increases after stopping marijuana ↗
Two epilepsy patients with seizures controlled by marijuana experienced dramatic seizure increases upon stopping, documented by continuous video-EEG monitoring.
Marijuana use did not affect success at quitting cigarettes, but alcohol use did ↗
In 739 smokers, marijuana use did not affect quitting success, while alcohol use after quitting increased smoking urges and relapse risk.
Daily Cannabis Use Was Linked to Fewer CB1 Receptors. A Month Without Brought Them Back. ↗
Chronic daily smokers showed lower cortical CB1 receptor availability that returned to control-like levels after about four weeks without cannabis.
Higher-potency synthetic cannabinoids developed less tolerance than THC in monkeys ↗
Monkeys developed 9.2-fold tolerance to THC but only 3.6-4.3-fold cross-tolerance to higher-efficacy synthetic cannabinoids, consistent with receptor theory.
Teen marijuana users had reduced brain blood flow, but it normalized after 4 weeks of abstinence ↗
Teen marijuana users showed reduced brain blood flow in multiple regions, but all differences disappeared after 4 weeks of confirmed abstinence.
Nearly 1 in 10 weekend nighttime drivers in California tested positive for THC ↗
California roadside survey found 8.5% of weekend nighttime drivers tested THC-positive, ranging from 4.3% to 18.3% by jurisdiction, with rates increasing since 2007.
CB1 blocker reversed anxiety from stress hormones and cocaine withdrawal in rats ↗
CB1 antagonist reversed anxiety from stress hormones and cocaine withdrawal in rats through brain mechanisms independent of the hormonal stress axis.
Lowering the cannabis urine test threshold caught 25% more positive results in French military screening ↗
Lowering the cannabis urine test cutoff from 15 to 5 ng/mL caught 25.2% more positive results in French military screening without creating false positives.
Cannabis users with first-episode schizophrenia had earlier psychosis but better starting cognition ↗
Cannabis-using first-episode schizophrenia patients had earlier psychosis onset but better cognition, with 75% quitting cannabis spontaneously over follow-up.
Review of cannabinoid biology and clinical evidence for MS spasticity treatment ↗
Review confirming clinical trial evidence for Sativex in MS spasticity, with biological rationale from endocannabinoid system science.
Infertile men had lower endocannabinoid levels and altered cannabinoid system in their sperm ↗
Infertile men's sperm showed reduced endocannabinoid levels and absent TRPV1 receptors, identifying potential biomarkers and treatment targets for male infertility.
Schizophrenia patients who previously used cannabis showed different brain activation patterns during cognitive tasks ↗
Schizophrenia patients with cannabis history showed better task-related brain activation and less default-mode activity at rest than non-using patients.
Sativex for MS spasticity was effective but unlikely to be cost-effective in the UK ↗
Economic modeling found Sativex cost 49,300 pounds per QALY for MS spasticity, exceeding the UK's 30,000-pound cost-effectiveness threshold.
Growing evidence that cannabis could reduce reliance on prescription opiates for chronic pain ↗
Review finding cannabis enhanced opiate pain relief, prevented tolerance, and potentially reduced opiate dependence, positioning it as a harm-reduction strategy.
Large Australian twin study found cannabis use, abuse, and early onset were all highly heritable ↗
Large Australian twin study found 72-80% heritability for cannabis use, early onset, and abuse/dependence, among the highest for any substance.
How cannabinoids disrupt memory formation: they suppress the brain's replay signals ↗
Cannabinoids suppressed hippocampal sharp wave-ripples essential for memory consolidation by selectively inhibiting excitatory glutamate signaling.
Direct comparison: oral THC caused anxiety and psychotic symptoms while CBD had no measurable effects ↗
In the same 16 men, oral THC caused anxiety, psychotic symptoms, and sedation, while 600 mg CBD was indistinguishable from placebo.
French study: daily cannabis use raised the risk of trying other drugs 124-fold among teens ↗
French study of 29,393 teens found daily cannabis users were 124 times more likely to try other illicit drugs, modeled through a stage-based progression.
How heavy cannabis users actually smoke: first puffs are most intense, and intensity predicts withdrawal severity ↗
Objective measurement of cannabis smoking showed front-loaded puffing and dose-dependent prediction of withdrawal severity, especially sleep disruption.
CBD protected myelin-producing brain cells from inflammatory damage through ER stress reduction ↗
CBD protected myelin-producing brain cells from inflammatory death by reducing ER stress through a mechanism independent of known cannabinoid receptors.
From Teen Years to 38: Heavy, Long-Term Cannabis Use Tracked With Lower Cognitive Scores ↗
The most famous and debated cannabis study: 1,037 New Zealanders followed from birth showed up to 8 IQ points of decline with persistent adolescent-onset use — but subsequent twin studies and meta-analyses suggest the true effect is smaller and partly confounded.
Large Australian study: cannabis use during adolescence independently predicted self-harm ↗
In 1,943 Australian adolescents followed to age 29, cannabis use independently predicted self-harm (2.4x risk), with most self-harm resolving spontaneously.
Pilot trial of an antipsychotic medication for cannabis dependence showed reduced use and improved mood ↗
Open-label pilot of pericyazine for cannabis dependence showed reduced use and improved mood in 21 patients, warranting a randomized controlled trial.
Social Anxiety May Drive Cannabis Problems in People With Schizotypy Traits ↗
College students with schizotypy traits and higher social anxiety used cannabis more frequently and reported more cannabis-related problems than those without social anxiety.
Cannabinoid Hyperemesis Syndrome: When Heavy Cannabis Use Causes Severe Vomiting ↗
Four patients with chronic cannabis use developed recurring severe vomiting and compulsive hot bathing, all resolving when they stopped using cannabis.
New Chemical Compounds Can Precisely Target the Brain's Cannabis-Processing Enzymes ↗
A new class of chemical compounds can selectively block endocannabinoid-degrading enzymes in the brain, potentially offering pain and mood benefits without full psychoactive effects.
Cannabis-Dependent Young People Seeking Help Usually Have Multiple Mental Health Conditions ↗
Young people seeking treatment for cannabis dependence typically had multiple psychiatric diagnoses, especially anxiety disorders like PTSD and social phobia.
GPs Screen for Cannabis Problems More Than Nurses, but Both Face Barriers ↗
GPs screened for cannabis problems more than nurses, but both groups reported barriers including time, skills, and uncertainty about their role.
Cannabis and Dopamine: What Animal Brains Show About Reward, Cues, and Withdrawal ↗
Animal data place cannabis squarely in the dopamine reward circuit: dopamine rises with use and cues, and falls during withdrawal. Blocking endocannabinoid signaling blunts these effects.
Sativex Shows Promise for Multiple Sclerosis Spasticity in Clinical Trials ↗
Review of clinical trial data found Sativex (THC/CBD spray) reduced MS spasticity symptoms and improved patients' ability to perform daily activities.