Marijuana's Minimal Impact on Next-Day Performance, Study Finds

A recent study has found that using marijuana before sleep has minimal impact on various performance measures the following day, including driving simulation, cognitive tasks, psychomotor functions, subjective effects, and mood.

Study Overview and Key Findings

The study, part of a larger investigation into the effects of THC and CBD on insomnia, involved 20 adults with diagnosed insomnia who rarely used marijuana. Conducted by researchers from Macquarie University, the University of Sydney, Royal Prince Alfred Hospital, Griffith University, and Johns Hopkins University, the study revealed that a single oral dose of 10 mg THC combined with 200 mg CBD did not significantly impair next-day cognitive function or driving performance compared to a placebo.

"The results of this study indicate that a single oral dose of 10 mg THC (in combination with 200 mg CBD) does not notably impair 'next day' cognitive function or driving performance relative to placebo in adults with insomnia who infrequently use marijuana," the researchers stated.

Research Methodology

Participants were randomly assigned to receive either a placebo or 2 milliliters of cannabis oil containing 10 mg THC and 200 mg CBD. This dosage was chosen based on previous studies indicating that it could induce subjective effects like increased drowsiness without affecting cognitive and psychomotor performance in infrequent cannabis users.

In a follow-up session, participants who initially received the placebo were given the THC–CBD mixture, and vice versa. Cognitive tests were conducted within two hours of waking, and driving performance was measured 10 hours after administration using a fixed-base driving simulator. Participants also reported their subjective experiences, such as feeling "stoned," "sedated," "alert," "anxious," or "sleepy," at various intervals up to 18 hours after administration.