Aging, Cognition, and Medication Adherenceq ON Gould, Mount Allison University, Sackville, NB, Canada Ó 2017 Elsevier Inc. All rights reserved.
Extent and Cost of Medication Non-adherence in the Elderly Types of Non-adherence Adherence: A Complex Cognitive Task Prospective Memory and Episodic Memory: Age-Related Changes and Effects on Adherence Knowledge, Beliefs and Communication: Age-Related Changes and Effects on Adherence Measuring Adherence: A Difﬁcult Challenge Interventions: How Cognitive Psychology Can Help Further Reading
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Glossary External memory strategies Actions undertaken to support prospective memory whereby the physical environment is changed (e.g., the use of lists, notes, calendars and pillboxes). Internal memory strategies Mental actions undertaken to support prospective memory (e.g., linking planned activity with daily events). Medication non-adherence Failure to take medications as prescribed; this can include taking too few or too many doses, taking medication at incorrect times or in incorrect
quantities, or not following special instructions related to the medication (e.g., regarding food or beverages). Prospective memory Memory for actions to be performed in the future (e.g., remembering to take prescriptions at a prescribed time). Reality monitoring The ability to distinguish between actions that were planned and actions that were actually carried out. Retrospective memory Memory for events that occurred in the past (e.g., remembering the instructions received for when and how to take medication).
Extent and Cost of Medication Non-adherence in the Elderly Individuals over 60 years of age make up an increasingly large percentage of the population in industrialized countries around the world, and the trend is expected to continue for many decades to come. Indeed, the World Health Organization projects that the percentage of adults in developed regions will increase from 23% in 2013 to 32% in 2050. The majority of older adults suffer from at least one chronic illness; consequently, older adults are the largest consumers of medications of any age group. Many of the illnesses that afﬂict older adults can be treated or at least controlled quite successfully through the use of prescription medicationdif medications are taken as prescribed. Unfortunately, rates of adherence to medication regimens are known to be quite low. It is quite difﬁcult to establish adherence rates precisely, but in general, as few as 50% of patients treated for chronic conditions are believed to take their medications as prescribed. Rates of adherence are also thought to be particularly low in asymptomatic conditions such as hypertension that afﬂict many older adults. It is important to note, however, that “young-old” adults (those under 75 years of age) are often found to have high rates of medication adherence. Work by Denise Park and her colleagues indicates that older adults between 65 and 74 made the fewest number of adherence errors of any age group, although adults over the age of 75 made the most. The risks of non-adherence are numerous and serious. Up to 40% of hospital admissions in adults over the age of 65 are due directly to medication errors. Even though older adults do not seem to be more nonadherent than younger adults, they are more likely to experience serious health consequences because their bodies are less tolerant of medication errors and drug interactions. When treatment regimens are not followed, the risk of toxicity is heightened, medical conditions are likely to worsen, and expensive and often invasive treatments become necessary. Clearly, enhancing medication adherence is a priority for the effective treatment of chronic diseases, for enhancing the well-being of elderly individuals and for reducing health care costs.
Change History: October 2015. O. Gould updated the Further Reading section and made minor text changes throughout the article.
Reference Module in Neuroscience and Biobehavioral Psychology
Aging, Cognition, and Medication Adherence
Types of Non-adherence Medical non-adherence occurs when patients do not carry out medical regimens as prescribed and includes any of the following: (1) not taking the medication at all, (2) taking smaller or larger dosages than prescribed, (3) taking fewer or more dosages than prescribed, or (4) not following recommendations regarding food or beverages while medicated. Such behaviors can be either intentional (the patient chooses not to take the medication as prescribed) or unintentional (the patient intends to take the medication correctly but does not). In general, unintentional overuse or underuse of medication is due to cognitive variables such as forgetfulness or misinterpretation of instructions. Intentional non-compliance, on the other hand, can be seen as relatively more complex, and is linked to either external circumstances, or motivational issues. External circumstances include such factors as not being able to pay for the medication, not being able to reach the pharmacy to get the prescription ﬁlled, and not being able to open resistant packaging (e.g., childproof bottle tops) due to physical handicaps. Motivational issues refer to the fact that many individuals, both young and old, hold views about their illness and their medication that are incompatible with adherence.
Adherence: A Complex Cognitive Task In the past, medication adherence has been presented as an example of a simple everyday prospective memory task, where prospective memory is deﬁned as remembering to do things in the future. However, there is now a clear consensus that medication adherence is a complex process involving a host of variables. Although many of these factors are clearly cognitive, others, (e.g., motivation to adhere to the medication regimen), involve the interplay between cognitive and social factors. From a cognitive standpoint, the patient must understand the instructions for how to take the medication. These instructions are often complex, especially when multiple medications, each with its own regimen of doses and times, are presented. Thus, combining the information across multiple medications, and integrating all of this information with daily activities to form a plan of action, can be quite challenging. Once the plan of action is created, the patient must remember to take the medication at the correct time and must remember what dose and what medication to take. Moreover, the patient must keep track of whether or not the medication was taken so that extra doses are not taken inadvertently (i.e., reality monitoring). Reality monitoring can be particularly challenging when a medication for a chronic condition has been taken at the same time of day for months or years. Finally, the patient should monitor their health for a range of possible side-effects from the medication, including symptoms such as confusion and forgetfulness.
Prospective Memory and Episodic Memory: Age-Related Changes and Effects on Adherence Clearly, cognitive factors such as language comprehension (e.g., understanding the medication instructions), long-term memory (e.g., remembering what to do), working memory (e.g., juggling the competing demands of everyday tasks and medicationtaking), problem-solving (e.g., integrating complex medication instructions with the daily routine), prospective memory (e.g., remembering to take the medication at the correct time) and metamemory (e.g., monitoring memory performance and judging whether external support is needed for adequate adherence) are all involved in determining whether correct adherence will occur. Although age-related losses in many of these areas have been clearly established, many older adults are able to maintain high levels of performance, especially on everyday tasks like medication-taking. Many language abilities are maintained into very old age. However, the ability to seek, comprehend and use complex medication instructions (i.e., health literacy) may depend heavily on working memory capacity as well as language abilities. Age-related losses in working memory and problem solving are well-documented. It is clear that if information is presented quickly or is presented using an unfamiliar or disorganized format, many older adults will have difﬁculty comprehending and recalling the information. Many studies have shown that older adults are at a distinct disadvantage, compared with younger adults, when asked to combine complex medication instructions into a plan of action, especially if the instructions require inferences. Such problems have also been found when older adults are asked to transfer medication into weekly pillboxes, especially if the pill-boxes did not contain multiple compartments for each day. To take medications correctly, the patient not only must understand the instructions when they are given, but also must remember these instructions over the days and weeks following the meeting with the physician. In general, age-related losses are also observed when the ability to recall verbal information after a relatively long interval (i.e., hours or days) is measured. However, age differences can be greatly reduced, at least for relatively healthy older adults, if environmental supports for recall are present. For example, if information is presented clearly, if multiple formats are used (e.g., written and verbal presentation), if recall is based on habitual or familiar activities, if cues for recall are present in the environment, and if the person is not distracted by competing stimuli at time of recall, age differences in episodic memory are greatly reduced or even eliminated. At the moment, more research is needed on the effects of environmental effects such as type and magnitude of routine and frequency of interruptions during medication taking on medication adherence, particularly in older populations. Although it is well-documented that there are age-related losses in working memory, problem solving and long-term memory, prospective memory does not always show the same rates of decline with age. For example, when asked to make a telephone call or mail a postcard at a certain time, older adults attain performance levels similar or superior to younger adults through the use of
Aging, Cognition, and Medication Adherence
memory strategies. This may help to explain why older adults do not make more medication errors than younger adults. Park and colleagues have speculated that adults in their 60s and 70s may have few adherence errors because (1) they are sufﬁciently focused on their health to adopt mnemonic strategies for medication (unlike middle-aged adults), and (2) they have the cognitive ability to adopt and use mnemonic strategies (unlike much older adults). One can speculate that the use of smart personal devices is likely to increase in this younger age group in the future, and that these devices may provide particularly useful cues and reminders for medication taking. In laboratory-based studies of prospective memory, it has been suggested that prospective memory tasks can be divided into time-based and event-based tasks. In a time-based task, the individual must accomplish the task at a certain time (e.g., “Take your pill at 8 a.m.”) whereas in an event-based task, the individual must accomplish the task when cued by a speciﬁc event (e.g., “Take your pill before breakfast”). Computer-based simulations of prospective memory tasks have shown that event-based tasks are easier for older adults to accomplish, especially if the accompanying background task is not particularly difﬁcult. This may also explain why many older adults report that the main strategy they use to remember their medication is to mentally link the medication with routine daily activities. It may also explain why some studies have found that tailoring medication regimens to patients’ routine enhances adherence signiﬁcantly.
Knowledge, Beliefs and Communication: Age-Related Changes and Effects on Adherence At least three major foci in the research on the motivational factors of adherence in old age can be identiﬁed. First, the beliefs and attitudes that the patient has about his or her illness have been shown to predict adherence. Some people may deny that they are ill, or not believe that their condition has serious consequences. Patients who are more knowledgeable about their condition are more likely to follow recommended medication regimens. This may also explain why social support has been found to predict adherence. It may be that signiﬁcant others play a role in motivating an individual to adhere. Providing cues or reminders to follow the prescription also may play a role. A second factor concerns the beliefs that the patient holds about his or her treatment. Beliefs about the effectiveness of the medication, about whether the regimen prescribed is appropriate, about whether medications cause uncomfortable side-effects, and about how important it is to adhere to medication regimens as prescribed have been shown to contribute to treatment adherence. Thus, some older adults may simply not believe that their medication is helpful. Others may choose underadherence to avoid sideeffects or may overmedicate because they believe that the prescribed dose is ineffective. (It should be noted that since many health care professionals lack extensive knowledge about the effects of medicationsdespecially multiple medicationsdon the older body, partial adherence may be beneﬁcial in at least some cases). Finally, a third set of factors revolves around the relationship with the health-care provider. This relationship is critical in many ways. Medication adherence can be seen as the outcome of a process that begins before the physician and patient even meet. Namely, the attitudes and the beliefs that each holds about each other are likely to affect patient-physician interactions in at least two ways. First, the quality of the interaction and the satisfaction that the patient feels with his or her health care are very important predictors of motivation to adhere to a medication regimen. Second, the relationship may also affect the quantity and the quality of the information that is exchanged during the patient-physician encounter. For adherence to occur, the patient must be told how to take the medication in detail, and must be informed about his or her condition and its associated risks. Unfortunately, many studies suggest that health care providers are less likely to provide this information to older patients than to younger ones, and older patients are also less likely to question their physician. Thus, even though older adults are likely to be taking more medications and to have more complex regimens, they are also likely to receive less information about their medications. Finally, the relationship between the health care provider and the patient also affects the quality of the information that the patient provides. In other words, the patient is more likely to provide accurate and detailed information about his or her symptoms, use of over-the-counter medications and herbals, and adherence to existing medications when the patient perceives the health-care provider to be caring and approachable. Such accurate information is key for the health care provider to be able to make accurate diagnoses and treatment decisions. In conclusion, even though the relationship between the health care provider and the patient is commonly addressed from a social psychology perspective, this relationship has important cognitive repercussions as well. The patients’ knowledge about the illness and medication, and his or her beliefs about the importance of adherence are often highly dependent on how well and how comfortably the patient communicates with the health care provider.
Measuring Adherence: A Difficult Challenge The difﬁculty of measuring medication adherence is well established and often discussed in the literature. Both technical and nontechnical approaches have been used. One technical approach has been the evaluation of body ﬂuids (e.g., blood or urine) for the presence of the prescribed medication. However, this technique only recognizes drugs ingested during the recent past and does not indicate whether the patient has taken the medication regularly. Pharmacy reﬁll rates and pill counts have also been used; however, with these methods, ﬂawed data is obtained if the patient is using multiple pharmacies, disposing of pills, hoarding pills, and/or sharing pills with others. The most accurate data comes from a specially designed pill bottles with a lid containing a microchip that
Aging, Cognition, and Medication Adherence
records every time the bottle is opened. However, even this system still does not provide an accurate measure of whether the drugs were actually taken when the pill bottle was opened and does not verify whether the correct doses were taken. Although these special pill bottles are useful for research purposes, their general use remains limited. The most convenient and the most often used means of assessing adherence is self-reports. However, it is clear that self-reports underestimate medication errors. Patients are likely to overestimate their adherence levels, not only because they do not recall errors, but also because they hope to avoid confrontations and/or embarrassment. Cognitive factors also contribute to the accuracy of self-reports. When asked to recall the frequency of a behavior, respondents are likely to reduce their efforts by estimating rather than counting, and this is especially true of older adults. Moreover, with older adults, memory complaints are often not predictive of objective memory performance. Thus, older adults who complain about having bad memories might not be the ones who make adherence errors due to forgetting. Despite the potential pitfalls of self-reports, the use of speciﬁc questions relating to recent medication adherence behaviors rather than general memory performance can be quite useful, particularly if the questions are asked in a supportive and non-confrontational way.
Interventions: How Cognitive Psychology Can Help Much of the intervention research has focused exclusively on compensating for either cognitive or motivational deﬁcits. Many studies have focused on providing older adults with external mnemonic strategies. Such strategies involve effecting changes in the environment so that it provides prospective memory cues. Many studies have been carried out to investigate the effectiveness of aids such as pillboxes and pill bottle alarms, memory training, voice mail reminders and organizational charts. Most of these studies found such memory aids to be at least somewhat effective in enhancing medication adherence, but no intervention has been shown to be clearly superior. Moreover, many of these studies were conducted over a short period of time, and neither young nor older adults are likely to continue using memory strategies assigned to them after the training period has ended. It is also interesting to note that the few studies that examine what strategies older adults use spontaneously tend to ﬁnd that internal strategies (i.e., using mental actions to help encode or retrieve information) are reported quite often. However, very little is known about the effectiveness of internal strategies for routinized, long-term prospective tasks such as medication adherence. Also, little is known about what drives the process of determining that a mnemonic strategy is necessary, deciding which one to use, and evaluating its effectiveness. One external strategy that is being adopted by many older adults is the use of pillboxes with daily compartments. However, as noted above, at least some older adults have difﬁculty transferring pills to the container correctly and dangerous errors may occur during this process. Moreover, many older adults use pill boxes with only one compartment per day, and these have been shown to lead to higher numbers of errors because patients get confused regarding which pill must be taken at what time. With all pill boxes, the medication is physically separated from the bottle and its label summarizing the name and intended use of the medication. In some areas, the use of individualized packaging is becoming more affordable and common. Some community pharmacies prepare blister packs for their older clients where each blister contains all the medication to be taken at a speciﬁc time (e.g., Monday morning). This packaging reduces the cognitive load related to planning the medication regimen and to monitoring whether the medication has been taken. However, this packaging can be bulky and more importantly can lead to difﬁculties when medications and dosages are changed frequently. Another approach that is used with increasingly frequency is the development of medications released into the body in a controlled fashion (e.g., slow-release pills) thus improving adherence by making frequent doses and complex regimens unnecessary. Finally, increases in adherence levels have also been obtained in studies that have addressed motivational factors. These studies have focused on improving the relationship between the physician and the patient, or tried to educate the patient as to the seriousness of the illness or the importance of the medication. In conclusion, many different interventions can be useful, but there is a growing recognition that the intervention applied must be tailored to the characteristics of the patient. Clearly it is not helpful to provide mnemonic strategies to someone who is nonadherent by choice, and neither is it helpful to convince someone of the importance of medications if the person cannot remember to take them. Thus, cognitive psychologists today are working in collaboration with health care providers to develop exciting multifaceted approaches that tailor cognitive and motivational interventions to the needs, abilities, and beliefs of individual older adults.
Further Reading Johnson, M.J., 2002. The medication adherence model: a guide for assessing medication taking. Res. Theory Nurs. Pract. An Int. J. 16, 179–192. MacLaughlin, E.J., Raehl, C.L., Treadway, A.K., Sterling, T.L., Zoller, D.P., Bond, C.A., 2005. Assessing medication adherence in the elderly: which tools to use in clinical practice? Drugs & Aging 22, 231–255. Murray, M.D., Morrow, D.G., Weiner, M., Clark, D.O., Wanzhu, T., Deer, M.M., Brater, D.C., Weinberger, M., 2004. A conceptual framework to study medication adherence in older adults. Am. J. Geriatric Pharmacother. 2, 36–43. Park, D.C., Liu, L.L., 2007. Medical Adherence and Aging: Social and Cognitve Perspectives. American Psychological Association, Washington, DC. Park, D.C., Morrell, R.W., Shifren, K., 1999. Processing of Medical Information in Aging Patients: Cognitive and Human Factors Perspectives. Lawrence Erlbaum Associates, Mahwah, NJ.