Single CBD dose did not change reward-related brain activity in healthy volunteers | Research

The takeaway

A single 600mg dose of CBD did not alter brain activity during reward anticipation or feedback in 23 healthy participants, based on fMRI during a monetary reward task.

Neuroscientists, addiction researchers, and those investigating CBD mechanisms of action.

600mg CBD: no change in reward brain activity vs. placebo

What the researchers found

In a double-blind, placebo-controlled crossover study, 23 healthy participants showed no differences in reward-related brain activity (measured by fMRI during a monetary incentive delay task) after 600mg CBD compared to placebo. Bayesian analyses confirmed similarity between conditions. Behavioral measures of reward motivation also showed no difference.

Why it matters

CBD has been proposed as a treatment for conditions involving reward dysfunction (e.g., addiction, depression). This well-designed null finding suggests acute CBD does not directly alter reward processing in healthy brains.

The numbers in context

23 participants; single 600mg CBD dose; no significant differences in whole-brain or ROI analyses; Bayesian analysis supported null finding.

How the study worked

Double-blind, placebo-controlled, repeated-measures crossover design. 23 healthy volunteers received 600mg oral CBD or placebo. fMRI measured brain activity during monetary incentive delay task targeting reward anticipation and feedback.

What this study cannot tell us

Small sample; single acute dose only; healthy volunteers (effects might differ in psychiatric populations); one specific reward task may not capture all aspects of reward processing.

How to read the evidence

Preliminary: small sample (n=23), single dose, healthy volunteers only.

When this study was published

Published 2020.

The bigger picture

Null findings from rigorous studies are important. If CBD does help with addiction or depression, it likely works through mechanisms other than directly altering reward circuitry, or its effects may only emerge in people with pre-existing reward dysfunction.

Questions still open

Would repeated CBD dosing show different effects? Does CBD alter reward processing in people with addiction or depression?

Common questions

Does CBD affect the brain reward system?

In this study, a single 600mg dose did not alter reward-related brain activity in healthy volunteers. Bayesian statistics confirmed the conditions were similar, making a missed effect unlikely.

Could CBD still help with addiction?

Possibly. The study tested only acute effects in healthy people. CBD might affect reward processing differently in people with addiction or through mechanisms not captured by this specific task.

Read the original research

The acute effects of cannabidiol on the neural correlates of reward anticipation and feedback in healthy volunteers.

Journal of psychopharmacology (Oxford, England), 34(9), 969-980

View on PubMed ↗Publisher’s paper ↗

Citation

Lawn, Will; Hill, James; Hindocha, Chandni; Yim, Jocelyn; Yamamori, Yumeya; Jones, Gus; Walker, Hannah; Green, Sebastian F; Wall, Matthew B; Howes, Oliver D; Curran, H Valerie; Freeman, Tom P; Bloomfield, Michael Ap. (2020). The acute effects of cannabidiol on the neural correlates of reward anticipation and feedback in healthy volunteers.. Journal of psychopharmacology (Oxford, England), 34(9), 969-980. https://doi.org/10.1177/0269881120944148