Browse more cannabis research, findings, methods, and limitations.
Experiment with 533 participants found graphic yellow health warnings on cannabis products were most effective at reducing appeal and increasing harm perception, with mental health and traffic accident themes most impactful.
EWAS in 2,310 veterans found four DNA methylation sites linked to cannabis use disorder independent of smoking, with the CUD-PTSD combination producing amplified epigenetic changes beyond either condition alone.
Prospective study of 2,943 trauma survivors found PTSD symptoms predicted increased substance use over time — with prior trauma and demographics determining who was most vulnerable.
In 404 trauma-exposed college students, restricted access to rewarding activities (not inability to feel pleasure) fully explained the link between PTSD symptoms and cannabis misuse.
Study of 80 male subjects found serum BDNF levels were highest in those with both cannabis use disorder and schizophrenia compared to either condition alone or tobacco-only controls.
Pilot study of 30 fibromyalgia patients found low-dose cannabis tea (100 mg/day Bedrocan) reduced pain from 8/10 to 4/10 over 6 months with improvements in physical and mental health quality of life.
Pilot trial of 32 patients found VR avatar therapy reduced cannabis use (d=0.80) with effects lasting 12 months in people with dual CUD and severe mental illness, confirmed by urine testing.
ABCD Study analysis of 10,395 children found no evidence that state recreational cannabis laws affected children's perception of cannabis risk over a 3-year period.
Italian survey of 2,024 MS patients found 15.5% used unprescribed cannabis (often for medical reasons), but only 36% disclosed use to their doctor, with 41% of non-users expressing willingness to try it.
Analysis of 12 years of NSDUH data found cannabis addiction was one of four substance addictions that stably predicted suicidal thoughts, planning, and attempts across all survey years.
Population study found IBD patients who used cannabis had 2x more ER visits, 1.9x more hospitalizations, and higher opioid use than non-users, but no increase in surgery or death.
Survey of 69,621 Canadian students found nearly half of dual alcohol-cannabis users reported impaired driving or riding exposure, with 9.5 times higher odds than alcohol-only users.
A rigorous crossover trial of 37 volunteers found high-dose CBD increased THC blood levels by 118%, boosted "Feeling High" by 60%, and did not improve pain relief, contradicting the assumption that CBD reduces THC effects.
Internet survey found 62 websites selling 128 synthetic cannabinoid vaping brands with misleading safety claims, bulk discounts, and easy accessibility on the regular web.
Interviews with 19 BIPOC pregnant cannabis users in California found they actively practiced harm reduction by reducing amounts, switching product types, and seeking regulated sources.
Open-label study of 20 daily e-cigarette users found 320 mg oral CBD reduced nicotine withdrawal severity and anxiety during a 4-hour abstinence period.
Survey found 65% of neurologists treating Parkinson's patients were unaware of contaminants in cannabis products, despite PD patients using cannabis at rates 1.5-2x higher than the general population.
Phase II/III RCT of 147 cancer patients found THC:CBD capsules tripled complete response for chemotherapy nausea from 8% to 24% versus placebo, with manageable side effects.
Norwegian 13-year longitudinal study of 1,988 youth found within-person cannabis use increases linked to anxiety, depression (males), and suicidal ideation (3.4x in males, 2.5x in females).
Among 342 heavy cannabis users at a French clinic, women had 3.9x higher dependence odds despite using less cannabis, and 5.5x higher lifetime PTSD, with most PTSD linked to sexual assault.
Qualitative analysis of an online pro-cannabis pregnancy forum found pregnant people described using cannabis for mental health, nausea, pain, and stress, often as an alternative to prescribed medications.
An 18-month UK registry study of 116 IBD patients found cannabis-based products were associated with improvements in disease-specific quality of life, anxiety, and sleep.
A longitudinal study of 894 pregnant individuals found cannabis use was associated with a sevenfold higher risk of fetal death and increased low birth weight risk.
An RCT found that an app-based parenting program was especially effective at reducing anxiety in parents who started using cannabis regularly during adolescence.
Among 163 chronic pain patients on buprenorphine for opioid use disorder, those with lower tolerance for physical discomfort used cannabis and alcohol more frequently.
A crossover RCT with 48 cannabis users found THC eliminated the tendency to look away from cannabis images. CBD did not change this effect, and adolescents responded similarly to adults.
Data from 323,896 US college students (2009-2019) showed the link between cannabis use and mental health problems grew substantially stronger over the decade.
A pharmacokinetic substudy of 23 MS patients found oral THC and CBD capsules showed wide individual variation in blood levels, with profiles similar to healthy volunteers.
MRI study of 223 teens and young adults found cannabis and nicotine each thinned the frontal cortex, but using both together partially offset the nicotine-related thinning effect.
Meta-analysis of 4 RCTs found cannabis users with PTSD still benefited from trauma-focused therapy, but attended fewer sessions and showed less improvement in other substance use.
A study of 1,618 trauma-exposed civilians found that heavy cannabis and alcohol users had worse PTSD and depression symptoms, with all groups peaking at 8 weeks posttrauma.
A Danish registry study of 35,714 schizophrenia patients found cannabis-related cases used less antipsychotic medication but had more hospitalizations, suggesting a potentially distinct clinical profile.
A survey of 2,462 adults in Canada's northern territories found 46% used cannabis, 22% daily, with three-quarters of products coming from legal sources.
A Danish nationwide study found prescribed medical cannabis for chronic pain was associated with doubled risk of new-onset arrhythmia within 180 days, though no link to heart attacks was found.
A survey of 102 women with IBD found nearly 19% used cannabis, but most were unsure about pregnancy risks and very few had discussed cannabis use with their doctors.
Annual Washington State surveys found young adult cannabis-impaired driving stayed at about 12.5% through the COVID pandemic, with no significant change from pre-pandemic trends.
A study of 1,941 Washington State young adults found peer approval of driving after combined alcohol and cannabis use predicted impaired driving behavior more than perceived prevalence.
Five years after Washington opened cannabis retail stores, alcohol DUI decreased and cannabis DUI held steady overall (11%) while dropping among cannabis users.
A survey of 1,467 young Canadian cannabis users found that male sex, frequent use, and peer driving norms most strongly predicted seeing cannabis-impaired driving as low risk.
Among 143 first-episode psychosis patients, cannabis use at program exit was linked to fourfold higher relapse risk and one-third the odds of continuing psychiatric care.
A Canadian study found cannabis use among IBD patients more than doubled after legalization (41% of CD, 31% of UC), but users had worse symptoms and quality of life.
A survey of 140 transplant clinicians revealed significant disagreement on cannabis policies for heart transplant listing, with state legality strongly influencing program practices.
A matched case-control study found prenatal cannabis exposure was linked to lower cognitive and motor scores at age three, with the most severe delays in language development among boys.
NHS prescribing data showed Sativex prescriptions for MS rose slightly from 2013 to 2022, but remained very low at about 5 per 100,000 people annually.
A survey of 434,104 US adults found daily cannabis use was associated with 25% higher heart attack risk and 42% higher stroke risk, with stronger effects in never-tobacco smokers.
A longitudinal survey of older US veterans in a medical cannabis program found improved pain and sleep outcomes, with 44% of opioid co-users stopping opioids at follow-up.
A 90-day study of 103 Pennsylvania medical cannabis patients found rapid quality of life improvements in physical functioning, emotional well-being, and pain within the first month.
A longitudinal study of 247 dyads found prenatal tobacco-cannabis co-exposure blunted emotional reactivity in toddler boys, while continued postnatal cannabis exposure heightened reactivity.
A 12-month study of 204 Oregon teens found that perceiving more peer cannabis use and having less ability to resist peer pressure predicted increasing hazardous cannabis use.
A nationwide study of 35,055 cyclical vomiting hospitalizations found cannabis use associated with shorter stays and fewer readmissions, likely because some cases were misclassified cannabinoid hyperemesis.