If It Helps You Sleep at Night: A Brief Conversation About Substance Use and Sleep
Let’s talk about nightcaps. No, I don’t mean the unstylish headwear relegated to TV and movie depictions of sleep in the ages before central heating. I mean the drink, often alcoholic, some people reach for at the end of their night to help them wind down from the day before drifting off to sleep. We live in a time where sleep hygiene tips lurk almost anywhere one seeks health information. Such lists often include a point or two about the damaging effects of alcohol and sleep, which may make the idea of a pre-sleep drink feel dated. With origins tracing back to the 19th century though, the nightcap has long been a fixture of folk-remedies for sleep difficulties (Cook, 2015), and we have reason to believe the thinking lives on, maybe even be shifting to other substances.
Depending on the subpopulation, somewhere between 5 and 25% percent of people in the United States report using alcohol, cannabis, or another substance to promote sleep (Canham & Mauro, 2017; Goodhines et al., 2019; Meneo et al., 2023). In those with chronic insomnia, estimates of alcohol use for sleep promotion are closer to 20-30% with about 67% describing alcohol as an effective sleep aid (Roehrs & Roth, 2018). Emerging evidence showing a nationwide decrease in alcohol use would suggest potential for a future decline in the use of alcohol as a sleep aid, but there are some who have theorized that such trends are associated with an increase in the use of cannabis-based products (Keyes, 2026). This claim is further supported by growing interest and openness in the use of cannabis-based products to support sleep (Dzierzewski et al., 2026) and confidence in cannabis’s effectiveness as a sleep aid among those who use it (Winiger et al., 2021). These trends become particularly interesting in relation to broader research on alcohol and cannabis as sleep aids: 1) Alcohol is associated with increases in sleep disruption and decreases in sleep quality (Gardiner et al, 2025), 2) Cannabis use has not been shown to be effective as a sleep aid with respect to total sleep time (i.e., sleep duration) or time to fall asleep (i.e., sleep onset latency) and has unclear implications for sleep quality (Velzeboer et al., 2025), 3) discontinuation of both alcohol and cannabis, even at low doses, after chronic use is associated with sleep disturbance, suggesting individuals may develop a dependence on the substance for normal sleep (Angarita et al., 2016).
It might be tempting to push back on the data with personal experience. Many people genuinely claim to feel the effects of a nightcap: they seem to fall asleep more quickly, stay asleep for longer periods throughout the night, or at the very least struggle to sleep on nights where they don’t have their nightcap of choice. These claims, however, can be explained by some behavioral science basics: reinforcement, conditioning, tolerance, and extinction. The brain sees certain psychoactive substances, particularly ones that affect our dopamine systems as rewards, and has a tendency to seek out such rewards. If your brain perceives benefit in that sleepy, relaxed feeling that comes from alcohol or cannabis use before bed, it’s likely to encourage you to seek out that reward again in the future (reinforcement). Over time, the brain creates an association between preparing for bed and anticipation of the substance, making the tendency to reach for the substance more automatic; if we go without the substance, we feel “off” because our brain is anticipating a reward that isn’t coming (conditioning). For substances like alcohol and cannabis, the brain and body tend to habituate to the amount of the substance we typically use, causing our typical dose to lose effectiveness over time unless we take more (tolerance). If we discontinue use, our brain will eventually “rewire” reinforced/conditioned responses so that we can learn to sleep without a nightcap (extinction), but the brain does not like to go without its rewards and tends to resist changes to automatic patterns, so typically sleep disturbance will get worse before it gets better (extinction burst). When a person is adamant about the effectiveness of a sleep remedy that is not backed by data, it's likely they are caught somewhere in this cycle.
Fortunately, psychological and behavioral tools such as sleep hygiene education, relaxation training, and mindfulness (all of which are components of Cognitive Behavioral Therapy for Insomnia, the frontline intervention for sleep disturbance) have emerged as strong options for promoting sleep without the use of psychoactive substances (Morin & Buysse, 2024). Such strategies pose no risk for physical dependence, minimize unintended side effects, can decrease reliance on substance use to promote sleep, and are associated with lower rates of long-term relapse to sleep disturbance than substance-based approaches. Put simply, psychological and behavioral interventions are likely to be more effective and more sustainable than alcohol, cannabis, or other nightcaps.
All of this said, it’s hard to override a sentiment that has been around for over one hundred years. If you’re not quite ready to put down your nightcap for good, here are some practical tips for managing the risks:
Keep the dose low - For both alcohol and cannabis, higher doses of use are associated with greater sleep-related problems. Lower doses are recommended to minimize risk
Keep use infrequent - Frequent use, particularly on consecutive days, increases the risk of dependence across a range of substances. Ideally, if one is able to safely abstain from use of a substance, it is best for them to use it as infrequently as possible, being particularly careful to avoid consecutive days of use
Leave plenty of time before going to bed - Use immediately prior to bed is most likely to create strong associations between a substance and sleep and, in some substances, increases the likelihood of interference. Research has defined “pre-bedtime use” as about three hours prior to going to bed, so it is recommended that an individual discontinue use of alcohol, cannabis, or other substances three hours before their typical sleep time (Gardiner et al., 2023).
Consult with a trusted doctor or sleep specialist - Qualified professionals are committed to being at the cutting edge of their fields and helping to pass that information along to those that they work with. If you have questions or doubts about your practices or things you have heard about substances for sleep, speaking with an expert in the field is almost always a good place to start.
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References
Angarita, G. A., Emadi, N., Hodges, S., & Morgan, P. T. (2016). Sleep abnormalities associated with alcohol, cannabis, cocaine, and opiate use: a comprehensive review. Addiction science & clinical practice, 11(1), 9.
Canham, S. L., & Mauro, P. M. (2017). Self-medication with alcohol: Aging issues. In Alcohol and Aging: Clinical and Public Health Perspectives (pp. 201-214). Cham: Springer International Publishing.
Cook, R. (2015). Oxford night caps: Being a collection of receipts for making various beverages used in the university. Read Books Ltd. (Original work published 1827)
Dzierzewski, J. M., Miller, A. N., Erickson, A. J., Nielson, S. A., & Dautovich, N. D. (2026). Use and interest in cannabis as a sleep aid: Results from a National Sleep Foundation population survey. Sleep Health.
Gardiner, C., Weakley, J., Burke, L. M., Roach, G. D., Sargent, C., Maniar, N., ... & Halson, S. L. (2025). The effect of alcohol on subsequent sleep in healthy adults: A systematic review and meta-analysis. Sleep Medicine Reviews, 80, 102030.
Goodhines, P. A., Gellis, L. A., Kim, J., Fucito, L. M., & Park, A. (2019). Self-medication for sleep in college students: concurrent and prospective associations with sleep and alcohol behavior. Behavioral sleep medicine, 17(3), 327-341.
Keyes, K. M. (2026). Are Americans sobering up? New trends in alcohol consumption in the United States. Addiction.
Meneo, D., Bacaro, V., Curati, S., Russo, P. M., Martoni, M., Gelfo, F., & Baglioni, C. (2023). A systematic review and meta-analysis of the association between young adults’ sleep habits and substance use, with a focus on self-medication behaviours. Sleep Medicine Reviews, 70, 101792.
Morin, C. M., & Buysse, D. J. (2024). Management of insomnia. New England Journal of Medicine, 391(3), 247-258.
Roehrs, T., & Roth, T. (2018). Insomnia as a path to alcoholism: tolerance development and dose escalation. Sleep, 41(8), zsy091.
Velzeboer, R., Malas, A., Wei, S., Berger, R., Parmar, V., & Lai, W. W. (2025). Cannabis and sleep architecture: A systematic review and meta-analysis. Sleep Medicine Reviews, 102164.
Winiger, E. A., Hitchcock, L. N., Bryan, A. D., & Bidwell, L. C. (2021). Cannabis use and sleep: expectations, outcomes, and the role of age. Addictive behaviors, 112, 106642.