Drugs save lives - but what about their side effects? Who can remember them?
Wednesday, November 5, 2014
Statins reliably reduce cholesterol levels and help save lives by preventing or ameliorating cardiovascular disease. But they have side effects: About 1 in 10 people suffer nosebleeds, a sore throat, headaches, or muscle and joint pain, to name but a few of the common side effects.
On balance, however, statins are widely believed to be saving lives.
So what were those side effects again? Can you still remember them?
A recent study by Michael Friedman and colleagues, published in the Psychonomic Society’s journal Memory & Cognition, has addressed the processes underlying people’s memories for side effects of medication. Friedman and colleagues focused in particular on elderly people, an important issue in light of the fact that 81% of senior citizens have been found to use at least 1 prescription medication, and that 29% use at least 5 prescription medications concurrently.
As Friedman and colleagues note, “it is often necessary for people to accurately monitor and be aware of all of the potential side effects that are associated with a particular medication, and to know which side effects could be indicative of a serious complication. Given the fact that a majority of medications are associated with a lengthy list of potential side effects, one’s ability to remember these side effects can be paramount in monitoring one’s health.”
In their first experiment, Friedman and colleagues presented their participants—college students and people in their 70s—with a list of side effects that could be classified into three levels of severity: mild (e.g., itching), moderate (e.g., heartburn), and severe (e.g., stroke). After rating the side effects for severity, participants had to recall the entire list of effects.
Older adults remembered more severe and moderate side effects than mild side effects, whereas a reversed patterns was found for the younger participants: They remembered mild side effects the most, followed by severe and moderate effects. What might explain this pattern? Friedman and colleagues suggest that it may reflect relative experience. After all, younger people in general are less likely to have had any first-hand experience with moderate or severe side effects whereas they are likely to have experienced mild ones. Conversely, older adults may have more first-hand experience with all three categories of side effects, not only because they have lived longer but also because experience with moderate and severe side effects may grow with age in unison with the growing need for medication. Averaging across severity, there was no difference between the two age groups: Old and young adults recalled the same number of side effects overall.
In a second, broadly similar, experiment all side effects were mild or moderate. Intriguingly, both age groups again recalled the same number of side effects, and if anything the older participants had a slight (but non-significant) edge. 
At first glance, finding no difference between age groups might sound like a pretty dull result—don’t experimenters conventionally strive to show differences between groups? In this instance, the lack of a group difference is, however, quite notable: In nearly all circumstances, large age-related declines are observed when participants have to recall information from memory. The fact that this pervasive deficit was absent here is thus surprising. Friedman and colleagues suggest that the better-than-expected performance of the older participants may reflect “…their relatively greater experience with medication and associated side effects.” In addition, the “…older adults could have found the to-be-learned material to be more valuable, emotional, or important than younger adults did,” thereby overcoming the age-related deficit that is conventionally found with other materials.
Older adults can remember information that is relevant to their lives and matches their experience as well as younger people. This adds to a small but growing body of literature that suggests that the functional relevance of memorial material is a crucial factor determining its retention—for example, it has been suggested that information is processed in terms of its “survival value”; thus, memory is improved when material has been acquired in the context of planning one’s survival in a remote desert.
Memory for side effects similarly serves an important “survival value” as it enables us to monitor our health. This ability is particularly important in light of the fact that many elderly people are taking multiple medications at the same time. To make things even more vexing, those multiple drugs can frequently be in therapeutic competition—a drug that alleviates one chronic condition may worsen another one.
It has been estimated that 20% of older Americans are exposed to therapeutic competition, which presents a challenge not only to physicians but to the memory of patients who need to keep track of multiple lines of side effects and symptoms.
 When people were asked to identify which side effects were arbitrarily labeled as “important” or “critical”, older adults were more likely to later misidentify some of the side effects as being critical. So although their recall was as good as that of young people, the older adults were less proficient at remembering arbitrarily applied classifications of the side effects.