Browse more cannabis research, findings, methods, and limitations.
A 30-day daily diary study of 111 young adults found that vaping nicotine and cannabis on the same occasion was linked to the highest consumption intensity for both substances.
A study of 153 teens with mood symptoms found that cannabis users reported worse anticipatory anhedonia, with more frequent use linked to greater difficulty looking forward to pleasurable experiences.
A brain imaging study found men with opioid use disorder had 15% lower cannabinoid CB1 receptor availability than healthy controls, particularly in emotion-processing regions.
Among multiple cannabinoid treatments tested in sleep-deprived mice, a CBD+CBC combination was the most effective at reversing memory impairment, depression, and brain inflammation.
A study of 587,486 pregnancies found that while any cannabis use was not linked to hypertension, frequent use (2+ times weekly) was associated with 3.44 times higher odds of hypertensive disorders.
A triple-blind crossover trial of 17 older adults with poor appetite found that a THC/CBD mouth spray did not increase caloric intake compared to placebo, though it was well tolerated.
A PET imaging study found cannabis use was linked to significantly lower brain MAO-B (an astrocyte marker) in early psychosis and high-risk individuals, particularly in striatal regions associated with dopamine.
A review proposes that cannabis may trigger psychosis in genetically vulnerable individuals by disrupting glutamate signaling in the brain's default mode network, and outlines how to test this hypothesis.
Two longitudinal studies found prenatal cannabis exposure was linked to DNA methylation changes in neurodevelopment genes, persisting from birth through age 27 across two countries.
A scoping review of 99 neuroimaging studies found that 85% detected differences in brain structure, function, or chemistry in cannabis users aged 14-25, though research quality was generally low.
A qualitative study of 24 Greeks found CBD-experienced patients reported benefits for pain and anxiety but wanted better guidance, while cannabis-naive patients were skeptical but open to regulated medical use.
Among 1,466 cannabis users with chronic conditions during COVID-19, 91% used cannabis medicinally for sleep, pain, and headaches, but most lacked medical guidance.
A study of 303,178 California pregnancies found that past-year violence and unsafe living situations were linked to higher cannabis use during early pregnancy, with 7.2% of pregnancies involving cannabis use.
A study of 167,504 teens found five substance use patterns, including a cannabis-centered class, and all groups had higher rates of depression, suicidal ideation, and violence than non-using peers.
A nationally representative study found 8.9% of US workers in their early 30s used substances at work, with 3.1% using marijuana, highest in food service and safety-sensitive jobs.
A Washington State survey found cannabis retail employees rated THC concentration as less important than customers, valuing terpene profiles and production methods more.
Among 530 psychiatric inpatients, cannabis use was linked to lower suicidal intensity in women but not men, with low psychological flexibility amplifying risk in male cannabis users.
Germany's 2024 national survey found 9.8% of adults (5.1 million) used cannabis in the past year, with 1% dependent, compared to 4.2% alcohol and 8.3% tobacco dependence.
A review found cannabis impairs attention while nicotine enhances it in adults, but both substances harm attention development when exposure occurs prenatally.
A 3-year study of 279 bipolar patients found cannabis linked to earlier onset and more psychotic symptoms but not more hospital readmissions, while tobacco predicted higher relapse rates.
An analysis of 47 YouTube videos found Delta-8 THC portrayed as a legal, milder cannabis alternative with easy access, while few videos were age-restricted.
US adults with disabilities were more likely to vape cannabis (4.6% vs 2.8%), with cognitive disability showing the highest rate at 8.2% and daily nicotine vaping as the strongest correlate.
A mouse study found prenatal THC combined with maternal stress caused additive harm to maternal behavior and offspring brain development, with sex-specific effects on anxiety, motivation, and gene expression.
CBD sped up extinction and prevented reinstatement of methamphetamine-seeking in rats, effects that were partially blocked by inhibiting D2 dopamine receptors in the hippocampus.
A study of five major cannabis companies found significant investment and employee flows from alcohol, tobacco, and pharma industries, raising concerns about profit-driven practices entering cannabis markets.
An ABCD Study analysis of 11,858 adolescents found psychosis symptoms were already rising before cannabis initiation, supporting self-medication and shared vulnerability models alongside any direct contributing risk.
A study of 731 18-year-olds found parent cannabis use predicted offspring use, but positive parenting in early childhood significantly buffered against cannabis use disorder symptoms.
A synthetic cannabinoid rescued memory deficits, reduced brain inflammation, and restored glucose metabolism in Alzheimer's mice without increasing anxiety.
JWH-018, a synthetic cannabinoid, caused arrhythmias, ischemic damage, and heart attack-like tissue changes in rats, with effects worsening at higher doses and longer exposure.
A review of 13 studies found emerging evidence that the endocannabinoid system may contribute to ADHD, with preclinical links between altered cannabinoid signaling and hyperactivity.
Survey of 229 cannabis users found 44.5% had used semi-synthetic cannabinoids like Delta-8 THC and THCP, with adverse effects reported across all product types.
Multi-state surveillance identified 30 cases of work-related asthma in cannabis workers, mostly from dust exposure in indoor cultivation, including two fatalities.
Review finds cannabis has been linked to heart attacks since the 1970s, but current studies are too coarse to identify which users and use patterns carry the most risk.
Experiment with 409 California youth found that cannabis ads with illustrations, food references, and positive sensation imagery significantly increased interest in cannabis use.
Placebo-controlled experiment found THC impaired cognitive efficiency more in lighter users than heavier ones, supporting the role of tolerance in moderating acute effects.
Thai poison center data showed cannabis hospitalizations rose from 69% to 97% across legalization stages, with more children exposed after recreational legalization.
Large database study found cannabis use associated with 30% lower mortality and less cirrhosis in liver disease patients, but 42% higher heart attack risk.
Mouse study showed combining alcohol with synthetic cannabinoids produced worse cardiac dysfunction than either alone, reversible by blocking CB1 receptors.
Twin study of 3,165 adults found cannabis use for sleep linked to worse sleep quality and more substance use, even after controlling for shared genetics.
Small study found a trend toward lower anandamide levels in newly diagnosed MS patients, with teriflunomide treatment linked to stronger endocannabinoid coordination.
National survey found 40.7% of current marijuana users also use CBD, compared to 5.1% of never-marijuana-users, suggesting substantial overlap between these populations.
Study of 719 breast reconstruction patients found cannabis users had three times the hematoma risk and nearly three times the readmission rate.
Mouse study found adolescent cannabinoid exposure primed lungs for worse bacterial infections in adulthood, amplified when combined with alcohol.
Pilot study of 13 CBD retailers in North Carolina found 92% displayed unapproved health claims, most commonly for stress/anxiety, arthritis, and pain.
Study of 406 gastroparesis patients found cannabis use independently associated with more ER visits and hospitalizations.
Daily tracking of 65 young people in cannabis treatment showed cannabis helped sleep in the first two weeks but the benefit disappeared by week three.
Small study of 51 daily cannabis users found risk-seeking predicted more negative consequences, while acting on positive emotions predicted fewer.
Randomized trial of 29 autistic children found CBD oil did not improve social responsiveness but significantly reduced anxiety and parental stress.
Survey of 102 opioid treatment clinicians found most lack medicinal cannabis experience but two-thirds would consider it for patients.
Clinician survey found over half of opioid treatment clients reportedly use cannabis, with recognized benefits for sleep and mental health alongside harms like dependence.