Browse more cannabis research, findings, methods, and limitations.
Among 75 marijuana users who lapsed after treatment, those who blamed themselves and saw the cause as permanent and pervasive were more likely to return to regular use over six months.
Delta-8-THC completely prevented vomiting in eight children aged 3-13 across 480 cancer chemotherapy treatments over up to eight months, with negligible side effects.
A cross-sectional study of 467 users found that dual tobacco-marijuana smokers reported lower tobacco consumption than tobacco-only smokers. Smoking habits decreased or stayed stable over time.
Brain recordings revealed two distinct cannabis-related deficits: attentional filtering worsened with years of use, while processing speed slowed with frequency of use, suggesting different mechanisms.
Self-efficacy for avoiding marijuana predicted frequency of post-treatment use better than complete abstinence. Cognitive-behavioral treatment only marginally improved confidence.
Among vocational high school students, 65% were heavy smokers by age 13, with strong associations with alcohol and marijuana use, poor grades, and multiple failed quit attempts.
Cannabis use before age 15 was associated with 2.7-30.8 times higher odds of mental health and behavioral problems, but most of this risk was explained by pre-existing family disadvantage and early adjustment difficulties.
The first survey of cannabis use in MS found 112 patients reported improvement in up to 14 symptoms, with spasticity and chronic pain most commonly improved.
In 131 children followed from birth, prenatal cigarette exposure was linked to lower reading and language scores in a dose-dependent pattern, while prenatal marijuana exposure showed no significant effect.
At controlled doses, alcohol and marijuana produced identical perceived impairment and comparable deficits on memory and processing speed tests. Neither affected reaction time.
Modifications at the C-1 position of THC-like compounds produced modest selectivity for the CB2 immune receptor over the CB1 psychoactive receptor, with one compound achieving a 4.5-fold preference.
Daily marijuana smoking produced tobacco-like respiratory symptoms, but COPD would likely require 4-5 joints daily for 30+ years. Cancer risk was documented in case reports but not quantified.
A 1997 Annals of Internal Medicine review supported pharmaceutical THC for nausea and appetite but concluded evidence did not support reclassifying crude marijuana as prescribable medicine.
THC suppressed macrophages, T cells, and NK cells and reduced infection resistance in labs and animals, but direct evidence of increased infections in human marijuana users was unavailable.
Prescription THC (dronabinol) showed no evidence of abuse, diversion, or street demand. Its slow onset and dysphoric effects made it unappealing even to cannabis-dependent individuals.
Case histories described bipolar patients who found cannabis useful for mania, depression, or both, with some reporting it more effective than conventional mood stabilizers.
A commentary acknowledged cannabis showed therapeutic promise for nausea and appetite but emphasized that controlled studies were lacking and risks must be weighed against benefits.
In nearly 2,000 female twins, whether someone tried cannabis was shaped by environment, but progression to heavy use and dependence was 62-79% heritable, driven primarily by genetics.
A 25-year research review found cannabinoids modulated all major immune cell types and altered resistance to multiple infections, while noting the endocannabinoid system's role in immune regulation needed further study.
All four common recreational substances (alcohol, caffeine, nicotine, marijuana) enter breast milk and can affect both milk production and the nursing infant.
A 1998 review called for removing research barriers to medical marijuana while noting the narrow therapeutic window as a major limitation, supporting pharmaceutical-grade cannabinoid development.
A landmark review described the body's own cannabis-like molecules (anandamide and 2-AG), their biochemistry, and introduced the "entourage effect" concept.
Endocannabinoid discoverer Mechoulam highlighted a UK-US divide on cannabis MS research, with Britain recommending "high priority" clinical trials while the US MS Society did not support cannabis use.
CB1 receptors were concentrated in the rat ciliary body, the eye structure controlling fluid pressure, providing a molecular basis for cannabinoid-based glaucoma treatment.
A pharmaceutical review found marijuana causes dependence but has less addictive power than cocaine, alcohol, heroin, or nicotine, and shows therapeutic promise for six conditions.
A major review found THC caused cell death in the hippocampus, produced persistent cognitive deficits, and activated the same dopamine reward pathways as morphine, alcohol, and nicotine.
Among 99 cannabis users, only those who started before age 16 showed lasting visual scanning deficits. Age of onset was the sole predictor, not total amount used or current intoxication.
Prenatal cigarette exposure reduced birth weight but children caught up quickly. Prenatal marijuana showed no effects at birth but was linked to smaller head circumference by early adolescence.
Two weeks of daily THC made rats hypersensitive to amphetamine's psychosis-like effects after withdrawal, supporting a biological mechanism for cannabis-associated psychosis risk.
Cannabis cachexia affects two-thirds of advanced cancer patients. Whole cannabis may be better tolerated than THC alone because CBD reduces psychoactive effects without blocking appetite stimulation.
In 199 smokers trying to quit, alcohol use predicted failure at all follow-up points. Marijuana use, whether at baseline or during treatment, did not predict smoking cessation outcomes.
Mechoulam reviewed 35 years from isolating THC to discovering endocannabinoids, noting a synthetic cannabinoid in clinical trials for brain injury while most medical use remained illegal.
Cannabinoid receptors are concentrated in brain movement centers. Limited clinical evidence suggested cannabis may help Tourette tics, Parkinson's dyskinesia, and some forms of tremor and dystonia.
A pharmacological roadmap identified clinical potential for CB1 agonists (spasticity, pain), CB1 antagonists (appetite, cognition), CB2 ligands, and endocannabinoid-boosting drugs.
A legal review of Washington State Initiative 692, which allowed medical marijuana possession with doctor documentation for qualifying conditions. Covered practical legal considerations for patients and providers.
31% of 566 adolescent marijuana users at alternative high schools quit within one year. Peer disapproval of drugs and negative personal attitudes about use predicted quitting.
A 1999 review of marijuana's historical medical uses and the research landscape, noting NIDA's decision to sell marijuana to private researchers for the first time and the potential for studying pain, wasting, and nausea.
Among 842 high-risk students, 70% used marijuana, over half had tried to quit and failed, and most viewed cessation programs as ineffective despite high interest in quitting.
Published in Nature, this landmark study showed cannabinoids reduced spasticity and tremor in MS mice, while blocking cannabinoid receptors worsened symptoms, revealing an active endocannabinoid control system.
An ethics review applied the principle of double effect to IOM evidence and concluded that denying medical marijuana to seriously ill patients violates their dignity and right to effective therapy.
Among drug treatment patients, 64% had alcohol dependence, 44% antisocial personality, and 24% depression. Cannabis dependence was higher in Caucasians and males, while women had higher depression and anxiety.
Analysis of 35,312 confiscated samples showed U.S. marijuana THC rose from under 1.5% (1980) to 4.2% (1997) while CBD and other cannabinoids remained unchanged.
Ecstasy users showed cognitive impairment on attention, memory, and intelligence measures, while cannabis-only users performed identically to drug-free controls.
In 232 first-episode schizophrenia patients, cannabis preceded psychosis in one-third, coincided with onset in another third, and began after symptoms in the final third, suggesting multiple pathways.
A respected pharmacologist proposed a six-month legal marijuana access program for patients with four conditions while collecting structured clinical data, bridging the gap between patient need and evidence.
In 1,198 male twin pairs, trying cannabis was influenced by family environment, but heavy use and dependence were 60-80% genetic, mirroring identical findings in female twins.
THC was detectable in saliva (64%) and forehead sweat (73%) of cannabis-positive injured drivers, offering non-invasive alternatives that better indicate recent use than urine testing.
Published in PNAS, CBD blocked arthritis progression in mice when given after symptoms started, protected joints, and worked through multiple anti-inflammatory mechanisms at an optimal oral dose of 25 mg/kg.
Both cannabis and ecstasy users had impaired verbal memory versus controls. Only ecstasy users showed additional delayed memory deficits. Neither group was aware of their cognitive impairment.
In 50 bipolar patients, alcohol abuse correlated with time spent depressed while cannabis abuse correlated with time in mania, suggesting each substance interacts differently with bipolar mood states.