Consuming cannabis in the evening does not impair cognitive ability or driving performance the following day, according to a study

Recent research has explored the effects of cannabis use before bedtime, specifically its impact on cognitive abilities, driving performance, and overall functioning the following day.

A study conducted by researchers from several prestigious institutions, including Macquarie University and Johns Hopkins University, provides us with valuable insights on this topic. The study, published in the journal Psychopharmacology, suggests that consuming cannabis before bed does not significantly alter cognitive functions or the next-day driving abilities in adults with insomnia and infrequent cannabis use.

Key study findings

The study included 20 adults with physician-diagnosed insomnia who were infrequent cannabis users. Participants received either a placebo or 2 milliliters of cannabis oil containing 10 milligrams of THC and 200 milligrams of CBD. The study aimed to understand the effects of cannabis on various performance measures the following day.

Cognitive and psychomotor functionsThe study evaluated cognitive and psychomotor functions using a series of tests. These included tasks of attention, working memory, and information processing speed. The results did not indicate significant differences between the placebo group and the THC-CBD group in 27 of the 28 tests. A minor reduction in accuracy (approximately 1.4 percentage points) was observed in the Stroop color-word test, but it was deemed clinically insignificant. The results highlight that «almost all cognitive tests performed, involving attention, working memory, information processing speed, and other domains, showed no THC/CBD effects the following day.».

Simulated driving performanceDriving performance was assessed using a fixed-base driving simulator 10 hours after cannabis administration. The study found no significant differences in driving performance between the THC-CBD group and the placebo group. This is in line with previous research suggesting that «driving skills in occasional cannabis users recover within 8 hours after oral administration of 20 mg of THC.».

Subjective effects and moodParticipants were also asked to report their subjective experiences, such as feeling «high,» «sedated,» «alert,» «anxious,» or «drowsy.» These effects were measured at multiple time points: at baseline, 30 minutes, 10 hours, 12 hours, 14 hours, 16 hours, and 18 hours after administration. The study found no notable alterations in mood or subjective effects the following day.

One of the important points raised by researchers is the comparison between the effects of cannabis and those of commonly prescribed sedative-hypnotics. Medications such as benzodiazepines and zopiclone are known to impair function the following day. The authors of the study It was noted that cannabis, in this context, did not present such effects, making it a potentially safer alternative for those seeking sleep aids.

Considerations and limitations

Although the results are promising, the researchers acknowledged certain limitations. The study's sample size was relatively small, and the findings were based on a single dose cannabis oil. This limits the possibility of generalizing the results to a broader population and understanding the effects of repeated dosing, which better reflects how some people use the medical cannabis for sleep.

Researchers have hypothesized that repeated doses may lead to the development of partial tolerance to disruptive effects of THC, which could potentially reduce the risk of hangovers. This aspect, however, requires further study.

Broader implications and related studies

The results of this study are consistent with other recent research on cannabis and cognitive function. A report published last December showed that prescribed medical cannabis had only a minimal acute impact on the cognitive functions of patients with chronic diseases.

A other study, published in March in the journal Current Alzheimer's Research, Suggests that cannabis use is associated with a lower risk of subjective cognitive decline, with users reporting less confusion and memory loss than non-users.

Furthermore, a study conducted in 2022 on the Cannabis and laziness revealed no significant differences between weekly cannabis consumers and non-consumers regarding apathy or reward-based behaviors. These findings suggest that cannabis use, particularly for medical purposes, may not have the often-assumed negative cognitive and psychomotor effects.