Research study · Cannabis & Cannabinoid Research · 2024
Acute and Extended Anxiolytic Effects of Cannabidiol in Cannabis Flower: A Quasi-Experimental ad libitum Use Study
Verified on PubMed Randomized controlled trial
A 2024 randomized controlled trial in Cannabis & Cannabinoid Research tested cannabidiol in anxiety. All participants reported anxiety reductions over the 4-week study. This study suggests that for patients seeking relief from anxiety symptoms, choosing cannabis flower high in cannabidiol and low in tetrahydrocannabinol may offer better outcomes than other ratios by reducing tension without.
In plain language
Study overview
Consider recommending CBD-dominant cannabis for patients with anxiety symptoms, as it may provide greater relief compared to THC-dominant options.
Findings
All participants reported anxiety reductions over the 4-week study. CBD-dominant cannabis use was associated with lower anxiety scores compared to THC-dominant use. Acute CBD-dominant use resulted in lower tension scores.
The deeper readScientific analysis
Objective: Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) have varying pharmacological actions with differential effects on acute and extended affective states, incuding anxiety. We aimed to study these effects on anxiety in legal market forms of cannabis.
Method: This study makes use of a nonequivalent control group quasiexperimental design. Forty-two participants with anxiety symptions who were not using cannabis were compared to 258 participants with anxiety symptoms who used cannabis flower (~3-4 times per week). Participants who used cannabis were randomly assigned to one of three legal market cannabis conditions; THC-dominant (24% THC, < 1% CBD), THC + CBD (12% THC, 12% CBD), or CBD-dominant (< 1% THC, 24% CBD). Changes in anxiety symptoms over 4-weeks were measured by the Patient Global Impression of Change (PGIC) scale and the Depression, Anxiety, and Stress Scale (DASS). Acute changes in subjective mood immediately after cannabis use were measured by the Profile of Mood States (POMS) Elation, Tension, and Paranoia subscales and the Addiction Research Center Inventory intoxication scale.
Results: While all participants reported anxiety reductions over the 4-week study on the PGIC (F = 30.65, p < 0.001) and DASS anxiety measures (F = 115.88, p < 0.001), ad libitum CBD-dominant cannabis use was associated with lower scores on the DASS anxiety subscale compared to THC-dominant use when accounting for frequency of use (difference = -1.03, SE = 0.45, p = 0.02). Similarly, acute CBD-dominant cannabis use was associated with lower scores on the POMS tension and paranoia subscales (POMS tension: CBD-dominant vs. THC-dominant: difference = -0.41 SE = 0.1, p < 0.001; CBD-dominant vs. THC + CBD: difference = -0.28, SE = 0.07, p = 0.04; POMS paranoia: CBD-dominant vs. THC-dominant: difference = -0.49, SE = 0.1, p < 0.001; CBD-dominant vs. THC + CBD: difference = -0.33, SE = 0.09, p = 0.01). Participants in all cannabis conditions experienced acute changes in positive mood and subjective drug effects.
Conclusions: This study provides novel information on the impacts of legal market cannabis with varying ratios of THC to CBD in indviduals with anxiety symptoms. Findings suggest that THC did not increase anxiety and that CBD-dominant forms of cannabis were associated with acute tension reduction that may translate to longer-term reductions in anxiety symptoms.
The paper
Citation
Bidwell LC, Martin-Willett R, Skrzynski C, Lisano J, Ortiz Torres M, Giordano G, et al. Acute and Extended Anxiolytic Effects of Cannabidiol in Cannabis Flower: A Quasi-Experimental ad libitum Use Study. Cannabis & Cannabinoid Research (2024). PubMed 38252547 · DOI
Limitations the authors noted
Quasi-experimental nonequivalent control group design where non-users were self-selected rather than randomized. Single-blind design where participants were unblinded following retail dispensary purchase due to mandatory commercial packaging labels. Ad libitum, naturalistic dosing precludes strict dose-control or placebo-controlled causal inference. Long-term frequency of product use and exposure between visits relied predominantly on self-report.
In practice
Why this matters
This study suggests that for patients seeking relief from anxiety symptoms, choosing cannabis flower high in cannabidiol and low in tetrahydrocannabinol may offer better outcomes than other ratios by reducing tension without increasing paranoia.
Browse related research
Condition: Anxiety Topic: Cannabis Topic: CBD Topic: THC
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Reviewed by Dr. Caplan on October 4, 2026.
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