Professor Harry Sumnall is a Professor in Substance Use at the Public Health Institute, Liverpool John Moores University, and a member of the UK Government’s Advisory Council on the Misuse of Drugs (ACMD).

In this conversation we break down the drug policy terms people constantly confuse — and why that confusion matters in real life.

We cover:

• What decriminalization actually means (and what it doesn’t)
• Decriminalization vs depenalization vs legalization
• Why illegal markets create unique harms (potency, adulteration, organized crime)
• The “continuum” approach: prevention → harm reduction → treatment → recovery
• Why education alone rarely changes behaviour — and what does
• Stigma and dehumanization: how they block help-seeking and worsen outcomes
• Why policy is rarely purely “evidence-based” — values and politics always play a role

If you’ve ever heard someone say “decriminalization = legalization,” this episode will fix that.