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Title: Cannabis Use in California Following Legalization of Recreational Use
Authors:   Linda Hill, Daniel Ageze, Renee Dell’Acqua, Alice Gold, Ilene Lanin-Kettering, Jill Rybar, Tom Shaughnessy, Sara Baird, and Thomas D. Marcotte
Year:  2025
Journal:  Cannabis & Cannabinoid Research

 

A new study by Linda Hill from the Herbert Wertheim School of Public Health and Human Longevity Science at UCSD, Tom Marcotte, from the Center for Medical Cannabis Research (CMCR), and others focused on cannabis use patterns in California in 2022–2023, following the legalization of recreational cannabis in 2016.

The cross-sectional study involved a detailed online questionnaire administered to over 15,000 respondents aged 21 years and older between December 2022 and February 2023.

Thirty-seven percent reported cannabis use within the past three months. Use frequency varied, with 38% reporting very frequent use (multiple times daily), 33% reporting frequent use (four to seven times weekly), and 30% reporting occasional use (three or fewer times weekly). Demographically, very frequent users were predominantly male, less educated, and had lower incomes compared to occasional users.

Most respondents reported using multiple types of products, primarily dried flower (80%), vaping products (66%), and edibles (61%). The majority sourced their products from dispensaries (77%), which users overwhelmingly believed to be licensed. Home was the most common location for use (93%), followed by use during entertainment (75%) and creative activities (45%). Concurrent use of alcohol (36%) and cigarettes (24%) was notable.

The study identified several factors associated with cannabis use frequency. For instance, users who started consuming cannabis at a younger age and those with lower educational attainment or income levels tended to use more frequently. Moreover, daily users often initiated cannabis use earlier in life.

Although many respondents reported perceived health benefits, there remains a significant information gap, as most users relied on informal sources rather than healthcare providers for cannabis-related information.

Read the full study here.

Citation: Hill L, Ageze D, Dell'Acqua R, Gold A, Lanin-Kettering I, Rybar J, Shaughnessy T, Baird S, Marcotte TD. Cannabis Use in California Following Legalization of Recreational Use. Cannabis Cannabinoid Res. 2025 Jun 9. doi: 10.1089/can.2024.0179. Epub ahead of print. PMID: 40489356.

 

Title: Cannabidiol (CBD) Treatment for Severe Problem Behaviors in Autistic Boys: A Randomized Clinical Trial
Authors:  Doris Trauner, Anya Umlauf, David J. Grelotti, Robert Fitzgerald, Andrew Hannawi, Thomas D. Marcotte, Caitlin Knight, Lauren Smith, Gisselle Paez, Jennifer Crowhurst, Alyson Brown, Raymond T. Suhandynata, Kyle Lund, Marlen Menlyadiev & Igor Grant 
Year:  2025
Journal:  Journal of Autism and Developmental Disorders


In the first placebo-controlled trial of purified cannabidiol (CBD) for autism, researchers from the CMCR at UC San Diego and Rady Children’s Hospital in San Diego investigated whether CBD could safely reduce severe behavioral problems in autistic boys aged 7–14. Thirty-nine participants completed at least one phase of the 20-week crossover study. Each child received both CBD (up to 20 mg/kg/day) and placebo for 8 weeks, separated by a washout period.

CBD was well tolerated, with no serious treatment-related adverse events. Primary outcomes included changes in the Repetitive Behavior Scale-Revised (RBS-R), Child Behavior Checklist (CBCL), and Autism Diagnostic Observation Schedule-2 (ADOS-2). Both groups showed improvement on the RBS-R and CBCL. When compared directly, the RBS-R Total Score favored CBD but did not reach statistical significance (Cohen’s d = −0.44; 95% CI: −0.96, 0.07; p = 0.095). CBCL Total Scores also improved in both groups, with no significant between-group difference (d = 0.30; 95% CI: −0.23, 0.83; p = 0.269). ADOS-2 scores improved only in the placebo group (d = −0.70; 95% CI: −1.20, −0.21; p = 0.007), although this effect disappeared after adjusting for concomitant medications; differences between treatment arms were not statistically significant (p = 0.115). Despite these null findings, many of the endpoints favored CBD without reaching statistical significance, and clinician observations suggested that 68% of participants showed meaningful behavioral improvements while on CBD. A strong placebo effect was observed, underscoring the need for blinded, controlled designs.

This study suggests that CBD may benefit a subset of children with autism who have severe behavioral challenges. Larger studies with more sensitive outcome measures are needed to confirm efficacy and clarify which children are most likely to benefit.

Read the full study here.

Citation: Trauner, D., Umlauf, A., Grelotti, D.J. et al. Cannabidiol (CBD) Treatment for Severe Problem Behaviors in Autistic Boys: A Randomized Clinical Trial. J Autism Dev Disord (2025). https://doi.org/10.1007/s10803-025-06884-y

 

A new survey from the AAA Foundation for Traffic Safety, conducted in collaboration with Tom Marcotte, PhD, Co-Director of the Center for Medicinal Cannabis Research, revealed that many cannabis users may be getting behind the wheel too soon after consumption. Over half of those surveyed (53%) admitted to driving an hour or less after cannabis use, believing their driving abilities were unimpaired or even enhanced. Dr. Marcotte’s research underscores that cannabis impairment lasts longer than users realize, highlighting a risky period when people incorrectly feel sober enough to drive safely. The study emphasizes that cannabis can affect reaction times and peripheral awareness, urging users and the cannabis industry to increase awareness about these underestimated risks.

Read the full article here. Read the study here

Title: Elucidating interplay between myrcene and cannabinoid receptor 1 receptors to produce antinociception in mouse models of neuropathic pain
Authors:  Alayoubi, Myra; Rodrigues, Akeesha; Wu, Christine; Whitehouse, Ella; Nguyen, Jessica; Cooper, Ziva D. O'Neill, Patrick R.: Cahill, Catherine M.
Year:  2025
Journal:  Pain

 

Chronic pain affects millions of people, and while cannabis is increasingly used for symptom relief, most research has focused on cannabinoids like THC and CBD. Far less is known about terpenes—aromatic compounds in cannabis that may also influence pain. One of the most abundant terpenes, myrcene, has shown potential analgesic properties in animal studies, though its mechanisms remain unclear.

Researchers at UCLA investigated the pain-relieving effects of myrcene in male and female mice with nerve injury-induced pain. Mice received various doses of myrcene (1–200 mg/kg) and were tested for mechanical pain sensitivity using von Frey filaments. The study also assessed cannabinoid-like side effects (e.g., reduced movement or body temperature), reward-related behaviors using conditioned place preference tests, and whether myrcene directly activates cannabinoid receptor 1 (CB1) using in vitro assays.

Myrcene significantly reduced pain sensitivity in a dose-dependent and sex-specific manner, with females responding at lower doses than males. The analgesic effect was blocked by a CB1 antagonist, suggesting involvement of the endocannabinoid system. However, myrcene did not directly activate CB1 receptors or enhance the effects of known CB1 agonists or endocannabinoids. Unlike THC, it did not cause sedation or hypothermia, but female mice showed behavioral aversion to myrcene.

These results suggest that myrcene may relieve pain by indirectly engaging the endocannabinoid system, possibly by increasing endogenous cannabinoid tone or acting on upstream pathways, without producing THC-like side effects. The observed aversion in female mice raises questions about tolerability and optimal dosing. Further research is needed to clarify the mechanism of action and evaluate the translational potential of myrcene in human pain management.

Read the full study here.

Citation: Alayoubi, Myraa,b; Rodrigues, Akeeshab; Wu, Christineb; Whitehouse, Ellab; Nguyen, Jessicab; Cooper, Ziva D.b,c,d,e; O'Neill, Patrick R.b,c; Cahill, Catherine M.b,c,d,*. Elucidating interplay between myrcene and cannabinoid receptor 1 receptors to produce antinociception in mouse models of neuropathic pain. PAIN ():10.1097/j.pain.0000000000003558, March 18, 2025. | DOI: 10.1097/j.pain.0000000000003558
 

 

Report: Examination of Cannabis Users’ Perceptions and Self-Reported Behaviors to Inform Messaging to Deter Impaired Driving

Type: Published Report
Title: Examination of Cannabis Users’ Perceptions and Self-Reported Behaviors to Inform Messaging to Deter Impaired Driving
Authors: Hill, L.L., Marcotte, T. D., Ageze, D. & Hacker, S. D.
Year: 2025
Source: AAA Foundation for Traffic Safety
Citation: Hill, L.L., Marcotte, T. D., Ageze, D. & Hacker, S. D. (2025). Examination of Cannabis Users’ Perceptions and Self-Reported Behaviors to Inform Messaging to Deter Impaired Driving (Technical Report). Washington, D.C.: AAA Foundation for Traffic Safety.

 

Background:

Cannabis use surpassed alcohol in the U.S. in 2022, and driving under its influence increases crash risk. However, effective deterrent strategies remain limited. Many users misperceive cannabis as less impairing than alcohol and believe police cannot detect impairment. This study interviewed experts (n=19) and surveyed 2,800 cannabis users across eight states to assess driving behaviors and test targeted messaging, informing strategies to reduce cannabis-impaired driving.

Results:

Experts recommended addressing misconceptions (e.g., cannabis is less risky than alcohol), using non-stereotypical messaging, and collaborating with the cannabis industry. Among 2,000 surveyed users, 84.8% drove the same day as use, with 53% driving within an hour. Only 29% believed police could detect impairment. The most effective messages emphasized impaired reaction time and legal consequences. Findings support targeted, fact-based interventions to deter cannabis-impaired driving.

3 messages were well received and scored best across most parameters:   

1. “Driving high is driving Impaired— Find a safe ride home”

2. “If you feel different, you drive different—Drive High. Get a DUI”

3. “THC slows reaction time, distorts perception, and increases the risk of a car crash—Don’t Drive High.”

 

Read the full report or report summary

Citation: Hill, L.L., Marcotte, T. D., Ageze, D. & Hacker, S. D. (2025). Examination of Cannabis Users’ Perceptions and Self-Reported Behaviors to Inform Messaging to Deter Impaired Driving (Technical Report). Washington, D.C.: AAA Foundation for Traffic Safety.