Acute and Extended Anxiolytic Effects of Cannabidiol in Cannabis Flower: A Quasi-Experimental ad libitum Use Study

Among people with anxiety symptoms who used cannabis flower about three to four times per week over four weeks, those using CBD-dominant cannabis (24% CBD, <1% THC) reported lower anxiety on the Depression, Anxiety, and Stress Scale compared to those using THC-dominant cannabis (24% THC, <1% CBD), even after accounting for frequency of use. Immediately after use, CBD-dominant cannabis was also linked to lower tension and paranoia ratings than either THC-dominant or balanced THC+CBD (12% each) cannabis. All cannabis groups showed acute improvements in positive mood and some drug effects, and all reported reduced anxiety over the study period. The findings suggest that CBD-dominant forms may offer acute tension reduction that could support longer-term anxiety relief, without THC increasing anxiety.

Study at a glance

Abstract

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. Clinical Trial Registration: NCT03491384.