Getting a good amount of high quality sleep appears to deliver great benefits to memory. Sleeping well primes the brain for learning and retention, sharpening focus and increasing attention span during waking hours. Research also shows sleep has a powerful influence over memory. Time spent in sleep—especially deep, slow wave sleep and REM sleep—plays a critical role in memory consolidation, the process by which newly acquired knowledge is converted from short-term to long-term memory storage. This process not only embeds long-term memories, it also clears the way for the brain to take in new information. In recent years we’ve learned a tremendous amount about this relationship between sleep and memory, and the importance of sleep in memory consolidation.
How do sleep medications affect this critical function? Despite all the recent attention paid to the role of sleep in memory, this is a question that has, until now, received little notice. Researchers at St. Luke’s Hospital Sleep Medicine and Research Center in Missouri investigated the impact of prescription sleep aids on memory consolidation
Their results suggest that under some conditions, some commonly prescribed medications for sleep may interfere with the memory-enhancing benefits of sleep.
Researchers examined the possible effects on memory of 2 different sleep medications: zolpidem and zaleplon. Zolpidem is the active ingredient in several frequently prescribed sleep medications, including Ambien, Ambien CR and Elduar. Zaleplon is the active ingredient in the prescription sleep aid Sonata. Both drugs belong to a class of drugs commonly known as sleep hypnotics. They have a sedative effect that aids physical relaxation, relieves tension and induces sleep.
The study included 22 adults who were free of sleep problems. Researchers had all volunteers sleep under 3 different 8-hour sleep periods during the course of the study:
Before and after each sleep session, researchers tested participants’ memory skills in two different ways. They used word-pair association tests to measure declarative memory. Most of what we think of as conscious memory is declarative—it is a form of memory that allows us to store facts, events, thoughts and ideas. They also tested procedural memory using a test involving finger tapping. Procedural memory involves recall for skills and tasks, most often using the body. We use procedural memories constantly, without consciously thinking about it, when we tie our shoes, brush our teeth, or type on our computers.
Analysis revealed changes to both types of memory consolidation after taking sleep hypnotic medication at bedtime. Participants performed worse on both declarative and procedural memory tests after nights sleeping with the aid of zolpidem taken at bedtime, compared to nights with the placebo and nights with zaleplon taken in the middle of the night. Researchers found no difference between the placebo and the middle-of-night zaleplon dose, in terms of participants’ performance on memory tests.
These results indicate that using sleep hypnotic medication may interfere with and diminish the brain’s work to consolidate memory during sleep. The research also suggests that timing may be a significant factor. Sleep medication taken earlier in the night—at bedtime—had a negative influence on memory, while medication taken later in the night did not. This initial study has provided an important first step in exploring the effects of prescription sleep aids on memory consolidation and other sleep-related brain functions, raising several questions that deserve follow up: Do dosage levels affect the influence of sleep medications on memory? Is timing of dose important to its effect on memory consolidation, and why? What role might age, or gender, play in this apparent influence of sleep medications on memory?
What’s not in question? The importance of learning all we can about the effects of prescription sleep aids. According to a recent report issued by the Centers for Disease Control, more than 9 million adults in the United States use prescription medication for sleep. That’s roughly 4% of the population relying on these medications to improve nightly rest. We’re also learning more about the complications that can arise from some prescription sleep medication. In early 2013, the FDA issued a safety alert pertaining to zolpidem, in response to research that showed certain nighttime dosages of the drug lead to excessive drowsiness in the morning. The research indicated that the standard dosage of drugs containing zolpidem, when taken at night, posed a risk for early morning drowsiness and impairment of activities including driving. These risks for impairment and drowsiness were highest for women. The FDA required the recommended dosages of zolpidem be lowered for women. The FDA also urged physicians to prescribe the lowest effective dose for all patients, and to fully discuss the risks of morning impairment. Also in 2013, a report issued by the federal government’s Substance Abuse and Mental Health Services Administration (SAMHSA) found sharp increases in the rise of emergency room visits that involved adverse reactions to zolpidem. The report included analysis of ER visits nationwide between 2005 and 2010, during which period zolpidem-related cases increased by 220%.
Does this mean there is no place for prescription sleep medications containing zolpidem or other sleep hypnotic drugs? No. Used on a short-term basis, with the guidance of a physician, these sleep medications can help to break the difficult and often intractable cycle of insomnia, and help get sleep back on track. For most people, however, the best long-term strategy is to develop a strong, sustainable sleep routine that does not rely on prescription sleep medication. There’s no question this takes work, but the rewards are worth it. Your sleep, your overall health—and perhaps your memory—will be better for it.
Michael J. Breus, PhD
The Sleep Doctor™