Browse more cannabis research, findings, methods, and limitations.
Among 42 cannabis users, higher use frequency was specifically linked to increased parahippocampal brain activation during memory encoding, while duration and age of onset showed no effect on this region.
Cannabis users who started before age 16 showed increased brain activation during working memory tasks compared to later-onset users, independent of total use, suggesting less efficient cortical processing.
THC and CBD had opposite effects on brain activation in the striatum, hippocampus, amygdala, and cortex across four cognitive tasks, and CBD pretreatment blocked THC-induced psychosis in 6 volunteers.
Methamphetamine neurotoxicity increased CB1 receptor expression across multiple brain regions in rats and reversed the anxiety effects of cannabinoid drugs from anxiogenic to anxiolytic.
A review explored why cannabinoids paradoxically cause vomiting in chronic users despite being established anti-nausea drugs, proposing mechanisms including receptor desensitization, metabolite accumulation, and differential brain vs gut effects.
A WHO study across 17 countries found the gateway drug sequence varies with drug availability and cultural factors, suggesting common causes rather than cannabis itself driving progression to harder drugs.
Both psychosis patients and controls showed negative implicit cannabis associations, but patients had stronger explicit negative awareness. Relaxation expectancies were the strongest predictor of actual cannabis use in both groups.
Analysis of 140+ herbal incense products from 2008-2009 showed manufacturers rapidly switched synthetic cannabinoid ingredients in response to German bans, making contents unpredictable for consumers.
In a small pilot trial, 71% of cancer patients receiving a THC/CBD spray achieved complete response for delayed chemo nausea versus 22% on placebo, added to standard anti-emetic therapy.
In FAAH knockout mice, repeated THC caused stronger tolerance, more CB1 receptor dampening, and bigger withdrawal than repeated anandamide at equally effective doses.
In 37 abstinent cannabis users, genetic variants in CNR1 and FAAH genes were associated with greater brain reward-area activation when viewing marijuana cues, with an additive effect of risk alleles.
A single amino acid mutation in the glycine receptor completely abolished the ability of CBD, ajulemic acid, and HU210 to modulate this pain-related receptor, identifying a critical molecular interaction site.
CBD disrupted the forward neural connection between the amygdala and anterior cingulate during fear processing, the first demonstration that CBD affects brain network dynamics, not just regional activation.
A review noted that THC-based medicines have established therapeutic uses but significant side effects and abuse potential, driving interest in endocannabinoid system modulators as safer alternatives.
Dividing saliva THC concentration by a regression coefficient provided acceptable population-level estimates of blood THC, useful for roadside surveys, though inaccurate when fewer than 15% had high blood levels.
A review argued that the potent immunological effects of cannabinoid agonists and antagonists are clinically relevant and should be considered in every prescribing decision for cannabinoid medicines.
Meth neurotoxicity increased 2-AG endocannabinoid levels and alcohol consumption in mice, effects that were blocked by a CB1 receptor antagonist and mimicked by a MAGL inhibitor.
Adolescent cannabis users showed memory recovery after 2-3 weeks of abstinence but attention accuracy remained impaired, suggesting different recovery timelines for different cognitive functions.
The first case report of cannabinoid hyperemesis syndrome in a psychiatric patient highlighted that the condition may be underrecognized in mental health settings where cannabis use is common.
Among 351 Hispanic women, pre-pregnancy marijuana use was associated with 23-49% lower likelihood of quitting smoking at pregnancy onset, alongside stress and heavy smoking.
A commentary argued for harm reduction through product composition changes, specifically reducing THC and increasing CBD in cannabis to lower psychosis and addiction risks.
For the first time, THC withdrawal was shown to produce anxiety-like behavior in mice on the elevated plus-maze, without affecting motor activity, establishing an animal model for cannabis withdrawal anxiety.
In 177 cancer patients with opioid-refractory pain, THC/CBD spray significantly reduced pain (43% responders vs 21% placebo), while THC alone did not reach significance, highlighting CBD importance in the formulation.
A chronic cannabis user experienced a heart attack with slow coronary flow but no arterial blockages, adding to case reports linking cannabis to acute cardiac events in people without typical risk factors.
A review described how chronic nicotine and alcohol each alter cannabinoid receptors, endocannabinoid content, and multiple other brain systems, reducing each other's withdrawal and increasing preference for combined use.
Among 4,075 young French adults, depression (OR ~8) and psychosocial factors predicted suicidal ideation, while cannabis use was not an independent predictor after adjustment.
In a simulator, high-dose cannabis impaired multiple driving measures while alcohol at moderate doses had fewer effects. Cannabis decreased speed while alcohol slightly increased it, with no synergistic effects at tested doses.
In 6 cannabis users, nabilone produced THC-like subjective effects and substituted for THC in drug discrimination, while methylphenidate did not, supporting nabilone as a potential cannabis dependence medication.
A review highlighted a new focus on cannabinoids' anti-inflammatory effects in cancer treatment, arguing that their ability to reduce chronic inflammation could be as important as direct anti-tumor effects.
Brief review linking cannabis use in adolescents to psychosis, depression, panic attacks, and suicidal thoughts.
Among 130 teens, heavy drinking predicted worse verbal memory, but only in those who did not also use marijuana.
Review of how endocannabinoid and opioid systems modulate nicotine addiction, suggesting new treatment targets.
Systematic review of 41 brain imaging studies found cannabis affected brain function, especially prefrontal blood flow, but caused minimal structural changes.
The FAAH inhibitor URB597 helped rats forget morphine associations during extinction but did not prevent relapse when exposed to morphine again.
First documented cases of cannabinoid hyperemesis syndrome (severe cyclic vomiting) in two teenagers with chronic marijuana use.
Urine testing showed lower illicit heroin co-use in heroin maintenance (50%) versus methadone maintenance (71%), while cannabis use stayed high in both.
Blocking CB1 cannabinoid receptors reversed memory impairment during ecstasy withdrawal in mice, linked to hippocampal CB1 receptor upregulation.
fMRI study found chronic cannabis users had heightened brain reward responses to money and reduced sensitivity to losses compared to non-users.
Review identified three cellular mechanisms of cannabinoid-opioid interaction: peptide cross-release, receptor-receptor interaction, and converging signaling pathways.
In 169 first-episode psychosis patients, cannabis use was linked to earlier onset and appeared to override the COMT gene's protective delay effect.
Review of brain imaging studies found white matter abnormalities in early schizophrenia, with adolescent cannabis use having specific effects on these measures.
Daily marijuana users with past alcohol problems drank 52% more during marijuana abstinence; those without alcohol history showed no increase.
Heavy cannabis users were slower at recognizing dynamic facial emotions, requiring greater intensity before identifying sadness, anger, and happiness.
CBD reduced cardiac dysfunction, inflammation, fibrosis, oxidative stress, and cell death in diabetic mice and human heart cells exposed to high glucose.
Review found emerging evidence linking habitual cannabis smoking to COPD, pneumothorax, respiratory infections, and potentially lung cancer.
Chronic cannabinoid treatment impaired male rat sexual behavior; forced CB1 receptor blockade restored function while spontaneous withdrawal did not.
Review identified four mechanisms of cannabinoid immunosuppression through CB2 receptors: cell death, proliferation block, cytokine suppression, and regulatory T cell induction.
fMRI showed recreational drug users (ecstasy/cannabis) needed more brain activation for impulse control despite normal task performance.
Socially isolated rats showed increased endocannabinoid system gene expression in brain regions relevant to schizophrenia, including higher CB1 and lower FAAH in prefrontal areas.
First-episode schizophrenia patients who used cannabis showed better attention and executive function than non-users, both initially and after one year.