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Evaluating Next-Day Impairment from Nighttime Use of Medicinal Cannabis in Insomnia Patients: A Pilot Study

Groundbreaking Study: Cannabis and Next-Day Cognitive Function
Groundbreaking Study: Cannabis and Next-Day Cognitive Function

Next-Day Safety with Nighttime Cannabis

The increasing use of medical cannabis for treating sleep disorders has brought forth concerns about its potential next-day impairment, particularly in activities like driving and workplace performance. This pilot study evaluating the "next-day" effects of cannabis on adults with insomnia produced interesting results.

Study Overview

This study, published in the journal Psychopharmacology, investigates the effects of nighttime use of a cannabis oil containing THC (10 mg) and CBD (200 mg) on next-day cognitive and psychomotor performance in insomnia patients. The study aimed to understand whether the residual effects of THC, known for its psychoactive properties, could impair daily functions the next day.


Participants: The study included 20 adults with physician-diagnosed insomnia who had infrequent cannabis use histories. The participants were 16 females and 4 males, with an average age of 46.1 years.

Design: A double-blind, placebo-controlled, crossover design was used. Participants underwent two 24-hour laboratory visits, receiving either the THC/CBD combination or a placebo, separated by a seven-day washout period.

Procedures: Participants' cognitive and psychomotor functions were assessed approximately 9-11 hours post-drug administration using various tasks, including the Digit Symbol Substitution Task, Divided Attention Task, and simulated driving performance.

Key Findings

Cognitive and Psychomotor Function:

  • Out of 28 tests, only the Stroop-Colour Task (easy/congruent) showed a slight decrease in accuracy (-1.4%) for the THC/CBD group compared to the placebo.

  • No significant differences were observed in other cognitive tasks.

Simulated Driving Performance:

  • No notable differences were found between the THC/CBD and placebo groups in driving performance metrics such as standard deviation of lateral position (SDLP), headway, and speed control.

Subjective Effects:

  • A slight increase in feelings of sedation was noted 10 hours post-treatment in the THC/CBD group. However, there were no significant differences in self-reported alertness or sleepiness.


The study concludes that a single dose of 10 mg THC combined with 200 mg CBD does not significantly impair next-day cognitive or psychomotor function, nor does it affect simulated driving performance in adults with insomnia. This finding is crucial as it suggests that the evening use of this medicinal cannabis combination is unlikely to pose significant next-day risks for activities requiring cognitive and motor skills, such as driving.

Implications for Medical Cannabis Use

This pilot study's results are promising for the use of medicinal cannabis in treating insomnia without significant next-day impairment. However, further research with larger sample sizes and repeated dosing is necessary to fully understand the long-term effects and potential development of tolerance.


The findings provide a preliminary reassurance that nighttime use of a medicinal cannabis product containing THC and CBD does not significantly impair next-day function in adults with insomnia. This could have positive implications for those using or considering the use of medicinal cannabis for sleep disorders, especially concerning their ability to safely perform daily activities the following day.


  • Suraev, A., McCartney, D., Marshall, N. S., et al. (2024). Evaluating possible ‘next day’ impairment in insomnia patients administered an oral medicinal cannabis product by night: a pilot randomized controlled trial. Psychopharmacology.


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