Plain packaging and health warnings made cannabis products less appealing in a large experiment | Research

The takeaway

In a factorial experiment with 45,378 people in Canada and the US, plain packaging reduced cannabis product appeal while health warnings increased perceived harm and improved message recall, especially Canadian-style specific warnings.

Cannabis regulators, public health policy makers, packaging design researchers

Canadian-style specific warnings had higher recall than US general warnings

What the researchers found

Full branding was rated most appealing and plain packaging least (p<0.001). Health warnings made products significantly less appealing and more harmful than no warning (p<0.001). Canadian warnings (specific: pregnancy, adolescent risk, impaired driving) had higher recall than the US warning (general risk categories). White backgrounds with no branding were unexpectedly rated as less harmful than colored backgrounds.

Why it matters

As more jurisdictions legalize cannabis, packaging regulations can meaningfully influence consumer perceptions. This large-scale evidence from a randomized design provides actionable guidance for regulators.

The numbers in context

45,378 participants; 3x4 factorial design; plain packaging least appealing (p<0.001); health warnings reduced appeal and increased perceived harm (p<0.001); Canadian warnings had higher recall than US; white backgrounds rated less harmful (p<0.01)

How the study worked

Online factorial experiment randomizing participants to view cannabis packages across 3 health warning conditions (none, Canadian, US) and 4 branding conditions (plain to full branding). Measured product appeal, perceived harm, and free recall of warning messages.

What this study cannot tell us

Online experiment may not perfectly simulate real-world purchasing decisions. Self-reported appeal and perceived harm may not predict actual behavior. Only tested visual package design, not actual products. Short-term perceptions measured.

How to read the evidence

Large randomized factorial experiment with clear effects, providing strong evidence for packaging regulation impact on perceptions.

When this study was published

Published in 2021 using 2019 data.

The bigger picture

The lessons from tobacco plain packaging appear to transfer to cannabis. Regulations that restrict branding and require prominent, specific health warnings could reduce product appeal and increase risk awareness among consumers.

Questions still open

Would plain packaging regulations actually reduce cannabis consumption, or just shift purchasing to unregulated markets? Do the effects persist after repeated exposure to warnings?

Common questions

Do health warnings on cannabis work?

Yes. Products with warnings were rated significantly less appealing and more harmful. Specific warnings (like those used in Canada, mentioning pregnancy, youth, and driving risks) were better remembered than general risk statements used in the US.

Does plain packaging reduce appeal?

Yes. Moving from fully branded to plain packages significantly reduced product appeal. This is consistent with decades of evidence from tobacco plain packaging research.

Read the original research

Influence of package colour, branding and health warnings on appeal and perceived harm of cannabis products among respondents in Canada and the US.

Preventive medicine, 153, 106788

View on PubMed ↗Publisher’s paper ↗

Citation

Goodman, Samantha; Rynard, Vicki L; Iraniparast, Maryam; Hammond, David. (2021). Influence of package colour, branding and health warnings on appeal and perceived harm of cannabis products among respondents in Canada and the US.. Preventive medicine, 153, 106788. https://doi.org/10.1016/j.ypmed.2021.106788