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

> **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637)
> **Publisher:** CED Clinic (https://cedclinic.com)
> **Canonical URL:** https://cedclinic.com/research/cbd-for-anxiety-randomized-controlled-trial/
> **Published:** 2026-10-04T09:55:32-04:00 | **Last Modified / Clinically Audited:** 2026-10-04T09:55:33-04:00
> **Clinical Summary:** Consider recommending CBD-dominant cannabis for patients with anxiety symptoms, as it may provide greater relief compared to THC-dominant options.

---

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.

 

### Related

---

### Verification & Medical Governance

- **Lead Clinical Author:** Benjamin Caplan, MD
- **Credentials:** Board Certified in Family Medicine (ABFM), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House).
- **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`).
- **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/).
- **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637).
- **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).