Dose-dependent effects of cannabidiol in social anxiety disorder:
A randomized experimental therapeutics trial
July 24, 2025
At the July CMCR Investigators’ Meeting, Charles Taylor, PhD, Associate Professor of Psychiatry and Director, Positive Emotion & Anxiety Research Laboratory (PEARL) at UCSD presented findings from a novel randomized controlled trial that investigated the dose-dependent effects of cannabidiol (CBD) on social anxiety disorder. This Phase 2 study, funded by the NIH National Center for Complementary and Integrative Health (NCCIH), evaluated whether CBD could decrease threat reactivity and modulate plasma anandamide levels in adults with Social Anxiety Disorder (SAD).
Fifty-seven participants were randomized to receive either 300 mg or 900 mg of oral CBD or placebo for four days. Using a standardized public speaking challenge, the team measured anxiety responses through subjective distress ratings, state anxiety inventories, and self-reported negative cognitions. CBD plasma concentrations and anandamide levels were also assessed.
Findings showed that both doses of CBD reduced anxiety relative to placebo, with the 900 mg dose demonstrating more robust and consistent effects across anticipation, performance, and exploratory outcomes. A dose-response relationship was supported by both group comparisons and plasma CBD levels. However, contrary to hypotheses, CBD reduced – rather than increased – plasma anandamide levels, prompting post hoc considerations around sympathetic nervous system activity and context-dependent stress responses.
The study highlights the importance of dose selection in CBD research and provides preliminary support for advancing the 900 mg dose to longer-term trials. Although the anandamide findings were unexpected, the trial offers valuable insight into CBD’s anxiolytic potential and the complexity of cannabinoid biomarker interpretation.
This work represents one of the most rigorous trials of CBD for anxiety to date and underscores the need for targeted, mechanism-driven research in the cannabinoid space.
Dr. Taylor is an Associate Professor of Psychiatry at UC San Diego and the Director of the Positive Emotion & Anxiety Research Laboratory (PEARL). His research over the past 20 years combines experimental psychopathology and clinical trials approaches to anxiety and depressive disorders to identify and target processes that give rise to negative emotional states or inhibit the experience of positive emotional states, with a focus on developing and optimizing intervention approaches designed to enhance social connections and well-being.