CBD improved emotional face recognition while THC impaired it, and combining them neutralized the impairment | Research

The takeaway

In 48 cannabis users, inhaled CBD improved recognition of emotional facial expressions while THC impaired it, and combining CBD with THC prevented the impairment.

Read this if you're interested in how THC and CBD affect your ability to read other people's emotions.

CBD improved emotional recognition; THC impaired it; combined = no impairment

What the researchers found

Forty-eight cannabis users received THC (8mg), CBD (16mg), THC+CBD (8mg+16mg), and placebo by inhalation in a four-way crossover design. They then completed an emotional facial affect recognition task with faces showing fear, anger, happiness, sadness, surprise, and disgust at varying intensities.

CBD improved emotional face recognition at 60% intensity (moderate difficulty). THC impaired recognition of ambiguous faces at 40% intensity. When THC and CBD were combined, the impairment was eliminated, with performance similar to placebo.

Both THC alone and THC+CBD equally increased feelings of being "stoned," but CBD did not influence this subjective feeling. Frequency of cannabis use and schizotypy scores did not modify the effects. This was the first human study directly comparing different cannabinoids on emotional processing.

Why it matters

Recognizing emotions in others is fundamental to social functioning. THC's impairment of this ability may contribute to social difficulties in cannabis users, while CBD's protective effect suggests that cannabis products with higher CBD ratios could be less socially impairing.

The numbers in context

48 participants. 4 conditions (crossover). THC 8mg impaired recognition at 40% intensity. CBD 16mg improved recognition at 60% intensity. THC+CBD combination: no impairment. Both THC and THC+CBD increased feeling "stoned" equally.

How the study worked

Randomized, double-blind, placebo-controlled, 4-way crossover design. 48 volunteers (selected for high and low cannabis use frequency and schizotypy) received inhaled THC (8mg), CBD (16mg), THC+CBD (8mg+16mg), and placebo. Emotional facial affect recognition task with 6 emotions at 20-100% intensity.

What this study cannot tell us

Participants were cannabis users, so results may not generalize to non-users. Inhaled delivery of precise doses is difficult to standardize. The doses used may not reflect typical use. Single-session design does not address chronic effects.

How to read the evidence

Well-designed 4-way crossover RCT with 48 participants. Gold-standard experimental design for cannabinoid comparison.

When this study was published

Published in 2015. First human study comparing cannabinoid effects on emotional processing.

The bigger picture

The THC-CBD interaction is one of the most important topics in cannabis science. This study adds emotional processing to the list of domains where CBD appears to counteract THC's negative effects, supporting the argument that CBD-to-THC ratio matters for cannabis's impact on functioning.

Questions still open

Would higher CBD doses provide even greater protection against THC's emotional processing effects? Do high-CBD cannabis strains produce less social impairment than high-THC strains? Could CBD supplementation improve social functioning in regular cannabis users?

Common questions

Does cannabis affect your ability to read emotions?

THC impaired the recognition of subtle emotional expressions in this study, while CBD improved it. When THC and CBD were combined, the impairment was prevented, suggesting CBD-rich cannabis products may be less socially impairing.

Does CBD cancel out THC's effects?

For emotional face recognition, yes. The THC+CBD combination performed like placebo. However, both THC alone and THC+CBD equally produced the subjective "stoned" feeling, so CBD did not block all of THC's effects.

Read the original research

Acute effects of delta-9-tetrahydrocannabinol, cannabidiol and their combination on facial emotion recognition: a randomised, double-blind, placebo-controlled study in cannabis users.

European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 25(3), 325-34

View on PubMed ↗Publisher’s paper ↗

Citation

Hindocha, Chandni; Freeman, Tom P; Schafer, Grainne; Gardener, Chelsea; Das, Ravi K; Morgan, Celia J A; Curran, H Valerie. (2015). Acute effects of delta-9-tetrahydrocannabinol, cannabidiol and their combination on facial emotion recognition: a randomised, double-blind, placebo-controlled study in cannabis users.. European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 25(3), 325-34. https://doi.org/10.1016/j.euroneuro.2014.11.014