Short answer
Delta-9 THC causes the high from medical cannabis. THC binds CB1 receptors in the brain and spinal cord. CBD, the second common compound, does not cause intoxication at doses sold in stores. A product sold through a state medical program can still contain THC. The label matters more than the word medical.
What the high feels like
Reports list euphoria, relaxation, altered time sense, louder colors and sound, dry mouth, and slower reaction time. Short-term memory and coordination drop. Heart rate and blood pressure change in the first hour. Older adults feel those heart effects more. The same product can feel different across people and across sessions.
experiences with medical cannabis
THC to CBD ratio
Labels list THC and CBD as mg per dose or as a ratio. A 1:1 product has equal amounts. A 20:1 CBD product has 20 parts CBD to 1 part THC. Flower sold in state programs runs 15% to 30% THC. Higher THC carries more risk of anxiety, paranoia, and vomiting. Lab studies show CBD can blunt some THC effects, such as anxiety and memory problems. CBD also blocks the CYP3A4 and CYP2C19 enzymes. That block can raise THC and prescription drug levels in blood.
effects of medical cannabis use
Onset and duration by route
- Inhaled, smoke or vape: onset 1 to 10 minutes, peak 15 to 30 minutes, duration 2 to 4 hours.
- Oral, edibles, capsules, swallowed tincture: onset 30 to 120 minutes, peak 2 to 3 hours, duration 4 to 8 hours.
- Sublingual tincture: onset 15 to 45 minutes, duration 4 to 6 hours.
- Topical: no high in most cases. Skin absorption is low.
Edibles send more people to emergency rooms than inhaled forms. The delay pushes a second dose before the first one peaks.
Dose
Federal drug labels give fixed ranges. Dronabinol, a synthetic THC capsule, starts at 2.5 mg. Nabilone starts at 1 mg. Epidiolex, a purified CBD liquid, doses by body weight, up to 20 mg per kg per day. State medical cannabis has no standard dose. A common starting point is 1 to 2.5 mg THC, then wait two hours before adding more.
Side effects and risks
Short-term effects include dry mouth, red eyes, fast heart rate, anxiety, panic, paranoia, and poor balance. High doses can cause acute psychosis in people with no prior history. Regular high-dose use links to cannabis use disorder, tolerance, and withdrawal: irritability, insomnia, and lost appetite. Cannabis hyperemesis syndrome causes repeated vomiting and stomach pain in long-term users. Hot showers give brief relief. Cannabis smoke contains tar and irritants. Vaping avoids tar but carries lung risks of its own.
Federal and state status
The FDA has not approved the cannabis plant for any medical use. It has approved three related drugs: dronabinol, nabilone, and Epidiolex. As of 2024, 38 states and the District of Columbia run medical cannabis programs. State law does not change federal law. Possession stays illegal under the Controlled Substances Act.
CBD products and the high
Full-spectrum CBD oil can hold up to 0.3% THC by dry weight under federal law. That trace amount does not cause a high in most users. It can show up on a drug test. CBD isolate has no THC. Check the certificate of analysis for THC content, pesticides, and heavy metals before you buy.