Sleep Medication and Memory

According to a recent survey conducted by the Centers for Disease Control, there are more than nine million American adults who rely on prescription sleeping aids to help them get the rest that they need. That is an enormous number that represents approximately four percent of the population, so it is incumbent upon sleep researchers and scientists to make sure that they have a good understanding of the impact that these drugs may be having.  There have been a number of concerns voiced about the potential side effects of these powerful hypnotics, including an FDA safety alert that was issued in 2013 warning of excessive morning drowsiness that was a risk with taking the standard dosage of drugs containing zolpidem, particularly for women. Since Zolpidem is found in some of the most popular sleep medications on the market, including Ambien, Ambien CR and Elduar, this raised immediate concerns for many patients and physicians alike, and another recent alert suggested that initial dosing should be adjusted on a number of sleep medications in order to minimize this impact. In an effort to get a better understanding of some of the affects that these medications can cause, researchers at S. Luke’s Hospital Sleep Medicine and Research Center in Missouri recently conducted a study on whether and how prescription sleep medications impacted memory consolidation. This is a particularly important question because it is well known that getting the rest and high quality sleep that the body needs has been conclusively shown to provide memory benefit. It is also known that lack of sleep has a negative impact on memory. Sleep research has proven that it is the deep, slow-wave sleep and REM sleep that provides the most memory benefit and plays the largest role in converting new information that is stored in short-term memory into long-term memory. Sleep not only consolidates new information but also clears the way for new information to be learned. The St. Lukes’ researchers set out to determine whether taking sleeping medication in any way affected this process. Their results showed a suggestion that the drugs may in fact interfere with memory consolidation, especially under specific circumstances. [caption id="attachment_487" align="alignright" width="300"]What are the links between popular sleep medications and memory? What are the links between popular sleep medications and memory?[/caption] The researchers focused their study on two popular sleep medications: zolpidem and zaleplon. As stated above, zolpidem is found in Ambien, Ambien CR and Elduar, while zaleplon is the active ingredient found in another popular prescription sleep aid, Sonata. Each of the medications falls into the category of drugs known as sleep hypnotics, which work by making patients that take them relax physically so that they can fall asleep. The researchers recruited 22 adult volunteers that had no reported instances of sleep disorders or insomnia. Each participant was studied in three different 8-hour sleeping circumstances: having been given a placebo, having been given a dose of zaleplon in the middle of then night, and having been given a dose of zolpidem when they went to bed. The study’s purpose was not only to gauge the impact that the drugs had on memory, but also to see whether there was a difference in the impact based upon the time at which the drug was taken. Participants were given word pair association tests designed to measure declarative memory and finger tapping tests designed to measure procedural memory both before and after each sleep session that they engaged in. Declarative memory is associated with remembering facts, ideas and thoughts, while procedural memory involves how a specific skill is accomplished. The results of the study clearly showed that there were changes to the participants memories following each of the medications, with both declarative and procedural memory having suffered for having taken either or zaleplon or zolpidem at bedtime. However, they study also showed that the greater impact came with having taken the medication at that time of night then with taking it in the middle of the night. Participants’ scores on the memory tests were the same for the middle of the night dosage as they were for the placebo. This means that there is something about taking the hypnotics that diminishes the brain’s ability to consolidate memories, and that the timing of when the medication is taken that is particularly important. The earlier in the evening that prescription sleep medications are taken, the greater the impact on the ability to remember, while there was no such impact when the drugs were taken in the middle of the night. Though researchers do not yet understand why the timing would be so critical, the results of the study clearly open new lines of inquiry, inviting questions about dosage levels as well as regarding the timing of dosing these medications. Answering these questions, as well as many others regarding potential side effects and risks involved with taking sleeping aids is very important as more and more Americans struggle with sleep and continue to turn to prescription sleeping aids as an easy answer to a complicated problem. The use of sleep medications has been found to be related to morning  impairment, as well as other concerns. Zolpidem has been specifically targeted by  the Substance Abuse and Mental Health Services Administration because of the increase in the number of emergency room visits that have been reported in those who use the drug. Over a five-year period there have been a marked increase in the number of adverse reactions that people have experienced. The goal of studies of prescription sleeping aids is not to eliminate their use, as they have been shown to be especially useful for those experiencing short-term sleeping problems. It is in those who have chronic insomnia and sleep disorders that the reliance on these medications, and the risks that are associated with them, raise concerns. For these patients, a behavioral approach targeting sleep habits, environment and other factors is likely a healthier approach.