The most commonly used substances that affect sleep are caffeine and alcohol. Most patients drink coffee and soda or tea, to some degree, on a daily basis. Alcohol use is also increasing. Many patients will complain of insomnia that may be directly related to their caffeine and alcohol use, without any clue that how this behavior is influencing their sleep. As providers, we have to remember to ask the appropriate questions about substance use when taking a history, including whether our patients are consuming caffeine and alcohol on a regular basis.

The half-life of caffeine is between three and seven hours but patients may experience sleep disturbances up to 10 hours after consuming their last caffeinated beverage. Caffeine is found in coffee, tea, soda, chocolate, stimulant medication, cocoa and over-the-counter analgesics and cold remedies.

Patients who use caffeine can experience insomnia, nervousness, excitability, flushed face and gastrointestinal upset. The effects of caffeine are prolonged in children, pregnant women and the elderly. Patients with hypothyroidism can become toxic with very small doses of caffeine. It may also trigger pain attacks in patients with pain disorders.

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Whether caffeine is addictive is questionable; however, ask those who haven’t had their morning coffee and they will quickly tell you they can tell a difference when they miss their java. Withdrawal symptoms do appear, including headaches, irritability, fatigue, dysphoria and flu-like symptoms. Patients are known to self-administer if they experience these symptoms, which reinforces the need for caffeine and the development of tolerance. If you recommend discontinuing caffeine, have the patient taper gradually.

Drinking alcoholic beverages close to bedtime can result in decreased total sleep time and decreases in slow-wave sleep. Alcohol does provide a transient sedative effect; therefore, many patients who are anxious or experience insomnia tend to drink prior to bedtime to help fall asleep.

But alcohol also increases snoring and apnea, which are health risks for patients with obstructive sleep apnea. In addition, alcohol use before bed increases periodic limb movements of sleep threefold. Other sleep disorders that increase with alcohol use include parasomnia activity, including sleepwalking and the risk for falling and becoming injured during sleep walking.

The concern for alcohol use and sleep goes beyond the bedroom. Patients who do not sleep well at night because of alcohol use are also more likely to be sleepy during the day. Therefore, driving accidents and workplace injuries can be elevated in this population.

Patients who are true alcoholics may experience sleep issues even one to two years after they stop drinking. Sleep tends to be shortened, shallow and fragmented and the percentage of REM sleep is often elevated. Unfortunately, because of these symptoms, patients often start drinking again. Needless to say, managing these patients’ sleep issues is very important during sobriety.

Nicotine is another often overlooked substance that affects sleep. However, smokers often have a difficult time falling asleep with increased arousals throughout the night. A new symptom has been described in established smokers called nocturnal sleep-disturbing nicotine craving. The prevalence in approximately 20% and is characterized by patients who wake up one or more times during the night and have to smoke before they can return to sleep.

Remember the importance of asking your patients about any substances they may be, using including illegal substances, to educate them about the health risks — not only to help improve sleep, but to encourage general well-being. Besides managing sleep issues, we also have to address the potential addictions patients may be experiencing, and refer them to the proper counselors who may be able to help.

Sharon M. O’Brien, MPAS, PA-C, works at Presbyterian Sleep Health in Charlotte, N.C. Her main interest is helping patients understand the importance of sleep hygiene and the impact of sleep on health.


  1. Gillin C, Drummond S, Clark C et al. “Medication and Substance Abuse.” Principles and Practice of Sleep Medicine. Fourth Edition. Philadelphia: Elsevier Saunders, 2005.