The short answer
The high comes from delta-9-tetrahydrocannabinol, or THC. THC binds to CB1 receptors in the brain and spinal cord. CBD, the second main compound in cannabis, does not cause a high. A medical product produces the same high as a recreational product with the same THC content and the same route of use. The label on the package does not change the pharmacology.
What THC does in the body
CB1 receptors sit in the cortex, hippocampus, cerebellum, and basal ganglia. THC attaches to those receptors. The result is altered timing, memory, and coordination. Doctors describe the effect as dose dependent. Five milligrams of THC and 50 milligrams of THC are not the same event.
medical cannabis high dosage control
Onset and duration by route
- Inhaled, smoke or vapor: onset 1 to 10 minutes. Peak at 15 to 30 minutes. Effects fade over 2 to 4 hours.
- Oral, edible or capsule: onset 30 to 90 minutes. Peak at 2 to 4 hours. Effects last 6 to 8 hours or longer.
- Sublingual tincture: onset 15 to 45 minutes. Duration 3 to 6 hours.
- Topical: no high in most cases. THC absorbed through skin does not reach the bloodstream at high levels.
Doctors cite two errors with edibles. Taking a second dose before the first dose takes effect. And treating an edible like an inhaled dose. Ten milligrams from an edible and one inhalation of 10 milligrams of flower do not deliver the same amount of THC to the blood.
Understanding Medical Cannabis High Dosage Control
Why medical doses are often lower
State medical programs let physicians and pharmacists set a starting dose. Common starting points are 1 to 2.5 milligrams of THC. Many medical products pair THC with CBD at ratios such as 1:1 or 1:20. CBD may reduce some THC effects, including anxiety and fast heart rate. Evidence on how much CBD blunts the high is mixed.
medical cannabis high explained by doctors
Side effects doctors track
- Short term: dry mouth, red eyes, fast heart rate, dizziness, anxiety, impaired memory, impaired coordination.
- Higher doses: panic, paranoia, vomiting, confusion.
- Daily long-term use: cannabis use disorder, bronchitis from smoking.
NIDA reports that about 3 in 10 people who use cannabis develop cannabis use disorder. Risk is higher for people who start before age 18.
THC impairs driving for several hours after use. Most states have no roadside test that maps to a legal impairment level.
Cannabis and other drugs
CBD inhibits the CYP3A4 and CYP2C19 enzymes. Those enzymes break down warfarin, clobazam, and some HIV and transplant drugs. THC adds to the sedation from benzodiazepines, opioids, and alcohol. Doctors advise telling every prescriber about cannabis use.
What to ask before you buy
- What is the THC milligram count per dose, not per package?
- What is the CBD to THC ratio?
- Was this batch tested for pesticides, mold, and heavy metals?
- How long should I wait before a second dose?
- Does this product interact with my current prescriptions?
What is not known
Federal law limits research. Few large trials compare whole-plant cannabis with placebo. Long-term effects on the lung and on adolescent brain development are documented but not measured in full.