Browse more cannabis research, findings, methods, and limitations.
Analysis of 116 patients found cannabis use did not reduce opioid withdrawal symptoms during a 10-week methadone taper, with results robust across 17 sensitivity analyses.
Longitudinal study of 816 people found externalizing disorders (conduct problems) predicted cannabis use disorder onset from ages 16-30, while depression and anxiety did not.
Review found preliminary evidence that smoked cannabis may worsen processing speed and memory in MS patients, who already face cognitive challenges from the disease itself.
A 13-year-old with cyclic vomiting had a false-positive cannabis urine screen caused by pantoprazole, highlighting a drug interaction that could lead to misdiagnosis of CHS.
35-year birth cohort study of 1,265 New Zealanders found regular cannabis use associated with lower education, unemployment, and psychotic symptoms, but many regular users experienced no harm.
Commentary on AAN review found prescription cannabinoids effective for MS spasticity and pain with insurance coverage justified, while herbal marijuana remains federally illegal and uncovered.
A 29-year-old presented with the classic CHS triad of cyclic vomiting, chronic cannabis use, and compulsive bathing, reinforcing the need to consider this diagnosis in chronic users.
Marijuana users had smaller hippocampal volumes, and combined marijuana-nicotine users showed an unusual inverted pattern where smaller hippocampus correlated with better memory.
Systematic review found only 3 of 42 outcome measures showed significant effects across 6 independently evaluated RCTs of school drug prevention programs, with only one program effective.
In 121 paranoia-prone individuals, intravenous THC increased paranoid thoughts through heightened negative emotions and anomalous experiences, not through cognitive impairment.
Among 140 Mexican suicide attempters, males were significantly more likely to use cannabis and alcohol with substance-related diagnoses, while females had stress-related diagnoses.
THC and endocannabinoid-boosting drugs reduced physical morphine withdrawal jumping in mice but did not block the emotional aversion, suggesting they address only part of the withdrawal experience.
Review of endocannabinoid system role in nicotine addiction found rimonabant helped smokers quit but had psychiatric risks, prompting research into safer alternative cannabinoid targets.
Topical 1% CBD cream reduced EAE clinical scores from 5.0 to 1.5, recovered paralysis, and decreased brain inflammation, demyelination, and immune cell infiltration in mice.
Systematic review and meta-analysis found cannabis use associated with ~3x increased risk of new manic symptoms and worsened mania in existing bipolar disorder.
Survey of 255 French medical students found cannabis users failed exams at 89% vs. 39% for non-users, with 10% of all students reporting suicidal ideation.
Commentary found almost no research on the cannabis-exercise relationship, despite widespread beliefs about both motivational impairment and performance enhancement.
CBD reversed social withdrawal, cognitive deficits, and brain inflammation (astrocyte and microglial activation) in a schizophrenia mouse model, matching clozapine's effectiveness.
Review found acute cannabinoid use impairs habit-based learning while chronic use enhances it, suggesting a novel habit-memory mechanism for cannabis addiction.
Among 371 juvenile detainees, cannabis use was 54% lifetime and 16% daily, far above general population rates, with daily users showing worse mental health but not more criminal involvement.
Among 96 bipolar manic patients, the dysphoric-psychotic subtype had higher rates of combined alcohol-cannabis use disorders and more suicide attempts than the pure elevated mania subtype.
Among 772 college freshmen, moderate drinkers who also used marijuana had significantly more blackouts, injuries, and DUIs than moderate drinkers who did not use marijuana.
Review for pediatricians found limited evidence for medical cannabis in developmental conditions and well-documented risks to the developing adolescent brain from regular cannabis use.
Novel CBD derivative HU-444 reduced arthritis severity, liver inflammation, and TNF-alpha production in mice without psychoactive effects and without the ability to convert to THC.
U.S. adult cannabis use more than doubled by 2012-2013. Use disorders nearly doubled in the population, while the share of users with a disorder fell from 36% to 31%.
Analysis of 1.3 million VA patients found more opioid prescriptions associated with higher rates of cannabis use disorder, suggesting the substances complement rather than substitute.
CBD triggered immune-suppressive cell mobilization in mice through mast cells and PPAR-gamma receptor activation, revealing a specific molecular pathway for CBD's immune effects.
Nursing guide to CHS emphasizes that standard antiemetics fail, narcotics may worsen pain, and abstinence from marijuana is the most effective treatment for this underrecognized condition.
Heavy adolescent marijuana users showed disrupted emotional development (no improvement in negative emotionality or resilience), with brain activation differences mediating the outcomes.
Among 480 Spanish undergraduates, 46% used multiple substances with cannabis-inclusive patterns most common, and use strongly correlated with close family and friends' substance use.
Ventilation at 11 air changes per hour eliminated all measurable secondhand cannabis effects (drug tests, sedation, cognitive impairment) that occurred under unventilated sealed-room conditions.
In a 4-way crossover study of 48 cannabis users, CBD improved and THC impaired emotional face recognition, with their combination preventing impairment.
THC/CBD spray maintained neuropathic pain relief (6.9 to 4.2 on 10-point scale) over 38 weeks in 380 patients without dose escalation, with 62% completing the study.
Combining a CB2 receptor blocker with moderate estrogen produced the same bone cell growth as 10x higher estrogen alone, revealing a synergistic interaction in human osteoblasts.
Review of schizophrenia etiology identified cannabis use as one of the two most important environmental risk factors, interacting with genetic vulnerability through epigenetic mechanisms.
Parent survey of 117 children with epilepsy reported 85% seizure reduction with CBD products, but the study authors explicitly warned of severe participation bias and lack of controls.
Study of 101 incarcerated Indigenous Australian men found family responsibilities and incarceration were the strongest motivators for quitting cannabis, suggesting culturally tailored cessation programs are needed.
Large U.S. survey found up to 20 joint-years of marijuana use did not impair lung function. Heavier use altered airflow patterns, but differently from tobacco-related lung disease.
Swedish study of nearly 80,000 twin and sibling pairs found that 75-90% of genetic risk for drug abuse is shared across cannabis, stimulants, and sedatives rather than being drug-specific.
Colorado ER visits for cyclic vomiting nearly doubled after medical marijuana liberalization, with affected patients 3.6 times more likely to report marijuana use.
24-month study found regular cannabis use significantly lowered remission rates in bipolar spectrum disorders, with the worst outcomes among those using both cannabis and tobacco.
Review of cannabinoid research for movement disorders found possible benefit for tics, potential neuroprotection in animal models, but no clear benefit for Parkinson's symptoms, tremor, or dyskinesias.
Controlled study of 16 adults found combining THC with methylphenidate produced additive heart rate increases and unique subjective effects, while THC impaired attention that MPH partially offset.
EEG study found high-dose THC disrupted automatic error detection in frequent cannabis users, while even low doses impaired conscious error recognition.
Controlled study found high-potency cannabis significantly impaired divergent thinking in regular users, while low-potency cannabis had no effect on creativity measures.
Clinical review found strongest evidence for cannabinoid pharmaceuticals in chemotherapy-induced nausea and AIDS-related appetite loss, with more limited cancer pain data.
Qualitative study found Baby Boomer cannabis users consciously substituted cannabis for alcohol, prescription drugs, and illicit substances, perceiving it as safer and less addictive.
Pilot study of 32 participants found that simultaneously treating cannabis and tobacco addiction was feasible and did not worsen cannabis outcomes, while reducing tobacco use.
Mouse study discovered multiple interacting mechanisms controlling GABA release in the hippocampus, including constitutively active CB1 receptors and opposing endocannabinoid pathways.
Survey of 1,811 young adult smokers found 46% called themselves social smokers but smoked alone too. Both social smoker groups were more likely to use and be dependent on marijuana.