Does cannabis actually calm you down?

In a double-blind trial, 120 regular cannabis users vaped placebo, 20 mg THC, or 40 mg THC. Self-reported stress dropped about equally in all three groups, while heart rate rose significantly more on the high dose than on placebo.

Stress relief is one of the most common reasons people give for using cannabis. This trial put that belief to a controlled test, and it is the first to track several stress systems at once. Researchers randomly assigned 120 regular cannabis users (56 men, 52 women, 12 non-binary or transgender participants) to vape one of three things without knowing which: placebo, a moderate 20 mg dose of THC, or a high 40 mg dose. Neither participants nor the researchers running the session knew the assignment. Stress ratings and saliva cortisol were collected before vaping, five minutes after, and an hour after, while a wristband continuously logged heart rate, heart rate variability, and skin conductance. The subjective result is the striking one: people reported feeling less stressed after vaping, but so did the placebo group, and by about the same amount, which points to expectancy rather than the drug. Physiologically, the picture split apart. Cortisol dropped more sharply on the high dose, and skin conductance responses dampened in both cannabis groups, but heart rate rose more on the high dose than on placebo. A key limitation: participants were all regular users tested in a lab, so this says little about occasional users or real-world stressful moments.