Oral cannabis at 25-50 mg THC markedly impaired cognition in infrequent users, with delayed onset and peak effects

In a placebo-controlled study with 17 infrequent cannabis users, 10 mg THC produced discriminable subjective effects and elevated heart rate but did not impair cognition. At 25 and 50 mg, pronounced subjective effects and marked cognitive/psychomotor impairment occurred. Effects were delayed 30-60 minutes with peak effects at 1.5-3 hours. Blood THC levels correlated with some effects but were substantially lower than after inhalation.

Randomized, placebo-controlled study in 17 healthy adults (no cannabis use for 60+ days) completing 4 sessions with cannabis brownies containing 0, 10, 25, or 50 mg THC. Subjective effects, vital signs, and cognitive/psychomotor performance assessed for 8 hours.

Edibles are a growing market segment, but their delayed onset leads to overconsumption. This controlled study quantifies the dose-response and time course, providing the evidence base for edible dosing guidelines and consumer education.

The "standard dose" of 10 mg in many legal markets appears appropriate for infrequent users: it produces effects without cognitive impairment. But 25 mg (only 2.5 standard doses) markedly impairs function. The narrow therapeutic window and delayed onset make edibles uniquely risky for inexperienced users.

Small sample (17); infrequent users only (frequent users may respond differently); single session per dose; laboratory setting (not real-world); brownie matrix may affect absorption; 8-hour observation may not capture full duration of higher doses.