How Cannabis Impacts Health & the Potential Risks | Dr. Matthew Hill
Dr. Matthew Hill, a professor at the University of Calgary and a cannabis biology expert, dives deep into the impact of cannabis on health. He discusses how THC and CBD affect the brain differently, including their links to appetite and stress regulation. The conversation tackles the risks of high-potency cannabis, its potential role in mental health issues, and whether it can be addictive. Listeners will gain insights into various consumption methods and the complex relationship between cannabis and cognitive functions.
Top snips
What is cannabis? THC vs CBD
8:00 – 10:18
Cannabis is a complex plant with 70+ cannabinoids. The main psychoactive is THC (delta‑9‑tetrahydrocannabinol) — this drives the “high”. CBD (cannabidiol) looks similar chemically but is non‑intoxicating and behaves differently.
- THC = intoxicating
- CBD = non‑intoxicating, different targets
Different terpenes add smell/flavor but their effects are unclear.
How THC hijacks the endocannabinoid system
17:44 – 18:42
THC acts mainly at the CB1 receptor, which endocannabinoids (anandamide & 2‑AG) normally regulate. Endocannabinoids act retrograde to keep circuits in balance — a thermostat for neurons.
THC is a partial agonist and when blanket‑applied it carpet‑bombs CB1 across circuits, producing the intoxicating state.
The ‘munchies’ — why cannabis spikes appetite
34:57 – 39:15
Cannabinoids engage hypothalamic feeding circuits and reward centers.
- They disinhibit AGRP neurons (drive food seeking).
- They boost sweet‑taste processing and reward salience.
Result: cannabis can override satiety and reward‑devaluation so satiated animals (and people) will still eat — hence the classic munchies.
Route matters: inhalation vs edibles
1:06:09 – 1:41:18
Inhaled THC: onset 2–5 minutes, titratable, blood peaks high (~100 ng/mL) then falls over hours.
Edibles: onset 30–90+ minutes, produce 11‑hydroxy‑THC (potent), longer high (4–8 hrs), and are easy to overdose by accident.
Takeaway: low and slow for edibles; wait before redosing.
Psychosis & cannabis — nuanced risk
2:09:13 – 2:12:51
Cannabis can trigger acute psychotic episodes in some people, but causality for chronic schizophrenia is unresolved.
Key points:
- Cannabis may be fuel on a fire — accelerating onset in vulnerable people.
- Genetic predisposition / family history (schizophrenia, bipolar) → avoid cannabis.
No clear population‑wide causal proof.
CBD: what works and what’s hype?
2:57:53 – 3:01:48
High‑dose CBD has proven benefit for some pediatric epilepsies (e.g., Dravet) — clinical doses are very large (hundreds–thousands mg).
Most over‑the‑counter CBD (2–25 mg gummies) has poor bioavailability and likely acts via placebo for anxiety/sleep.
CBD also affects adenosine and liver enzymes — drug interactions matter.