Cannabis & Cannabinoid Research

The effect of cannabis use on health is likely to depend on individual differences. In particular, there is a growing need to understand the impact of cannabis and delta-9-tetrahydrocannabinol (THC) on brain and behavioral health across the lifespan.

We conducted a narrative review summarizing the effects of cannabis and THC across three stages of life: in utero, adolescence, and late adulthood. We also provide an up-to-date report on past 30-day cannabis use and risk perceptions from the National Survey on Drug Use and Health (NSDUH; 2002–2023) during pregnancy, adolescence, and late adulthood. We note that NSDUH data collected during 2020 and since 2021 are not directly comparable to earlier years due to shifts in data collection methods.

Recent epidemiological data indicate a potential reversal of both the escalating rates of cannabis use and low perceptions of risk among pregnant women and adolescents. Findings across preclinical and clinical studies support high perceptions of risk for individuals in utero and adolescence, when alterations in brain development indicate potential for susceptibility to neuropsychiatric disorders. The escalating rates of cannabis use and associated low perceptions of risk have shifted to the late adulthood population, which may face unique health risks associated with cannabis use.

Our findings emphasize the necessity for clinical and policy recommendations to mitigate the risks associated with cannabis use and to enhance public understanding of its implications on neurodevelopmental and psychiatric disorders. Continued research and educational strategies are essential to address these evolving trends and reduce harm.

This systematic review evaluated randomized controlled trials (RCTs) conducted specifically in participants with diabetes and painful peripheral neuropathy to assess the effectiveness and safety of medical cannabis, isolated cannabinoids, or nationally approved cannabis-based medicines as adjuvant treatment, compared with placebo or baseline.

Controlled clinical studies and RCTs in adults with diabetic peripheral neuropathy were eligible. Animal and in vitro studies were excluded. We searched PubMed, Google Scholar, Cochrane Library, and Scopus and screened 15,377 records; 35 full-text articles were assessed for eligibility, and 4 RCTs were included in the qualitative synthesis.

Three of four studies reported statistically significant reductions in neuropathic pain with cannabinoid-based interventions compared with placebo, whereas one trial did not demonstrate superiority. In two trials using vaporized or sublingual Δ9-tetrahydrocannabinol (THC), doses in the range of approximately 16–18 mg were associated with clinically meaningful pain relief in participants. Adverse effects, including dizziness and cognitive symptoms, were common but generally mild-to-moderate, and discontinuations due to adverse effects varied across studies.

Evidence from four small, heterogeneous RCTs suggests that cannabinoid-based therapies may reduce pain in some patients with diabetic peripheral neuropathy; however, the limited number of studies, variability in formulations and comparators, and risk of bias preclude firm conclusions regarding efficacy. Observed THC doses around 16–18 mg/day delivered via vaporized or sublingual routes should be viewed as preliminary, hypothesis-generating ranges rather than definitive recommendations. Larger, contemporary RCTs with rigorous risk-of-bias control, standardized outcomes, and detailed safety reporting are needed.

Pregnant people use cannabidiol (CBD) to treat nausea, insomnia, anxiety, and pain. However, CBD crosses the placenta and enters the fetal brain, where it can affect several targets important for brain development. While consumption of high doses of CBD during pregnancy has been shown to disrupt offspring neurodevelopment, pain sensitivity, and cognitive behavior in mice, lower doses have not been assessed.

We administered 10 mg/kg/day CBD by oral gavage to pregnant C57Bl6 mice from embryonic day 5 through birth. We used the puzzle box, the forced swim test, and Hargreaves thermal sensitivity behavior tests and electrophysiology to determine how prenatal CBD exposure affects postnatal behavior and prefrontal cortex physiology.

We show that oral consumption of 10 mg/kg/day CBD during pregnancy increases thermal pain sensitivity in male mouse offspring. Furthermore, the same dose impairs cognition and reduces excitability of the prefrontal cortex in female mouse offspring.

These data show that lower doses of CBD consumption during pregnancy can impair fetal brain development and postnatal behavior.

Cannabidiol (CBD) exhibits multiple therapeutic properties, but its use in advanced cancer patients raises concerns about potential drug–drug interactions (DDIs) due to polypharmacy. This study aims to look for evidence of DDIs between concomitant medications and CBD oil in a randomized placebo-controlled trial of CBD oil for symptom control (MedCan-1 parent study).

Surrogate measures were used to identify possible drug interactions: (1) the maximum mL of oil self-selected by patients in CBD or placebo groups in relation to opioids, specific drug groups, or individual agents; (2) the occurrence of any new or worse adverse effect in relation to the study arm and the concomitant medication classes/medications of interest.

The dose of CBD self-selected by participants was not related to opioid use or medications, including benzodiazepines and antipsychotics. The likelihood of developing an adverse effect while on study or when taking specific medications was not increased by CBD. Participants on paracetamol tolerated a higher dose of CBD.

Concerns regarding the development of clinically significant drug interactions when taking CBD in the context of anti-cancer and other concomitant medications at least in the short term may be unfounded.

Epidemiological data indicate that regular users of cannabis products may be protected from type 2 diabetes, although the mechanism is not understood. Observations from animal studies suggest that the cannabinoid, cannabidiol (CBD) may protect/improve glucose tolerance; an effect that may be partially mediated by favorable modifications to the gut microbiome. The aims of the current pilot project were to gain initial insight into the influence of short-term CBD ingestion on oral glucose tolerance, the gut microbiome, and inflammation in sedentary adults with overweight or obesity and free from diabetes.

Using a randomized, double-blind, repeated measures, parallel design, oral glucose tolerance was determined in 16 adults (6 males, 10 females) prior to and following 4 weeks of daily ingestion of either placebo or CBD (30 mg every 12 h). Fecal samples were collected at baseline and post-intervention.

Compared with placebo, CBD did not influence glucose tolerance (Matsuda Index: placebo-pre 7.6 [5.5], placebo-post 10.1 [5.5], vs. CBD-pre 11.7 [7.9], and hCBD-post 10.1 [10.2]; median [interquartile range]; p > 0.05). Characteristics of the gut microbiome or inflammation were not appreciably modified by CBD or placebo.

Short-term daily ingestion of low-dose CBD did not appear to favorably modify glucose tolerance in sedentary adults with overweight or obesity. It is possible that CBD may not account for the previously reported protection from type 2 diabetes bestowed to regular users of cannabis products.

Research has linked marijuana use with lower body mass index (BMI). The current study explores the correlation between marijuana use on BMI in the general U.S. population. It reports the prevalence of marijuana in adults in relation to BMI, overall and across the levels of important variables.

This study used a probability sample of U.S. adults 18 years of age and older from the 2016 through 2022 Behavioral Risk Factor Surveillance System, a telephone-administered survey. The survey collects data from a representative sample regarding health-related risk behaviors, chronic health conditions, and use of preventive services. The primary outcome variables are current (at least once in the last 30 days) and daily (at least 20 of the last 30 days) marijuana use.

The study sample consists of 735,921 participants in the surveys that completed the optional module on marijuana use. Prevalence of marijuana use in adults doubled during the study period (7.48% to 14.91%). The increase directly corresponds with a shift toward legalization of medical and recreational marijuana. On average, the prevalence of use is 9% higher when medical marijuana is legal and 81% higher when recreational marijuana is legal (vs. not legal). For obese individuals, prevalence of current marijuana use is 35% lower than for nonobese individuals on average. Lower prevalence of marijuana use in obese individuals is consistently observed across the levels of certain demographic variables, employment status, tobacco smoking history, marijuana legalization status, and certain medical conditions (asthma, arthritis, and depression). In 2022, the adjusted odds of current or daily marijuana use are significantly lower and similar among obese (vs. non-obese) (0.68, 0.69, respectively), such that reduced obesity does not require daily use. Similarly, the adjusted odds of current marijuana use decrease in similar fashion to daily marijuana use with higher BMI weight classification.

Marijuana use is correlated with lower BMI. As legalization and prevalence of the drug in the U.S. increases, the prevalence of obesity may decline. However, clinicians should view this outcome along with the known health risks associated with marijuana use.

Cannabis use disorder (CUD) is one of the most common substance use disorders (SUDs) worldwide and is frequently associated with high rates of polysubstance use; however, despite rising rates of polysubstance use disorders (PUD), the characteristics of individuals with both CUD and PUD remain unclear. This study, therefore, aims to examine social and clinical characteristics of adults diagnosed with CUD and comorbid PUD. It also aims to assess whether psychiatric disorders are linked to higher odds of PUD among individuals with CUD.

Using a nationally representative U.S. dataset, we assessed 972 individuals with past-year DSM-5 CUD, grouped as CUD only, CUD individuals with one additional SUD (CUD + 1), and CUD individuals with two or more SUDs (CUD + 2). Descriptive statistics summarized social and clinical presentations; multivariate logistic regression examined factors contributing to PUD, controlling for clinical diagnoses and childhood maltreatment.

Among CUD individuals, 89.3% (n = 868) used at least one other substance in the past year, with 34.2% (n = 332) using two or more. Both the CUD + 1 and CUD + 2 groups experienced significantly more severe childhood maltreatment than CUD only. After adjusting for controls, personality disorders were associated with membership in the CUD + 1 group (odds ratio [OR]: 1.88, p = 0.01); mood disorders were associated with a higher likelihood of being in the CUD + 1 group (OR: 1.50, p = 0.049) and CUD + 2 group (OR: 2.58, p = 0.005).

Mood and personality disorders were highly prevalent and linked with PUD in CUD cases. We recommend screening for these disorders in complex CUD cases.

The conscientious prescribing of antiemetics by chemotherapy-induced nausea and vomiting (CINV) risk was highlighted in the American Society of Clinical Oncology (ASCO) “Choosing Wisely” recommendations. The pharmacologic properties of medical marijuana (MMJ) may allow for decreased incidence of CINV; however, little is known about the effects of MMJ on the use of antiemetics. This study aimed to determine if MMJ cardholder status, which enables access to MMJ, is associated with antiemetic overuse among patients with cancer.

This population-based secondary data analysis examined a retrospective cohort derived from the linked Arkansas All Payers Claims Database (2013–2020) and MMJ cardholder registry (2013–2019). The cohort consisted of 20,558 patients with cancer aged 18 and older with a chemotherapy claim in an outpatient setting within 12 months of a cancer diagnosis. Exposure was a registration to receive an MMJ card that permitted access to MMJ. The primary outcome of interest was antiemetic overuse, as characterized by the ASCO recommendation. Antiemetic use associated with chemotherapy was identified through filled prescriptions and medical claims. Multivariable logistic regression, adjusted for baseline demographic and prescription characteristics, was used to calculate the adjusted odds ratios (aOR) of antiemetic overuse among MMJ cardholders compared with non-MMJ cardholders.

Among 20,558 eligible patients, 436 (2.1%) had an MMJ card at some point in the study period. Antiemetic overuse was identified in 7.5% of chemotherapy cycles. Compared with non-MMJ cardholders, MMJ cardholders were less likely to experience antiemetics overuse (aOR: 0.76, p < 0.001). Patients with fewer chemotherapy cycles and younger in age had higher odds of antiemetic overuse compared with those with more chemotherapy cycles. The risk of antiemetic overuse did not differ based on gender and rurality of residency. Route of chemotherapy administration, CINV risk category, and type of cancer also impacted the odds of antiemetic overuse.

The findings indicate that MMJ cardholders are significantly less likely to experience antiemetic overuse than non-MMJ cardholders. Further investigation into the use, effectiveness, and safety of cannabis for CINV mitigation is needed to inform patient and provider decision-making.