Contrary to popular wisdom, adolescents see themselves as more vulnerable than adults do, and they typically overestimate important risks.—Reyna and Farley 2006
Perceived vulnerability is an important construct in many models of health behav- ior (e.g., the Health Belief Model; Janz and Becker 1984). The basic idea is that people will be more likely to engage in an adherence behavior if they believe that there could be a negative outcome to not completing the behavior, and that they are vulnerable to experiencing that outcome. Individuals who do not perceive them- selves as vulnerable to a negative outcome are presumed to be more likely to be nonadherent. The research literature is actually equivocal on this point. In a recent meta-analysis, DiMatteo et al. (2007) found that perceived vulnerability (as indexed by disease severity threat) was associated with better adherence only when condi-
82 6 Adherence in Adolescence
tions were less serious (e.g., pharyngitis, asthma). For more serious conditions such as diabetes and end-stage renal disease, parent-perceived severity was associated with worse adherence. Moreover, there was a 14 % higher risk for nonadherence in children and youth with objectively poorer health. (Pediatric self-report was not reported.) DiMatteo et al. suggest that adherence may become increasingly diffi- cult when disease status declines, due to feelings of ineffectiveness and (it might be presumed) illness burnout. However, it should be noted that the findings were correlational, making definitive conclusions about causality elusive. Some studies have suggested a curvilinear relationship, with poorer adherence among patients who are asymptomatic and who have more severe symptoms, with adherence be- ing best among patients with active but relatively moderate symptoms (Bender and Klinnert 1998).
When youth risk behavior is discussed in the adherence literature, the focus is often on the notion of adolescent “invulnerability,” the idea that “adolescents often believe themselves to be invincible to the consequences of risk-taking behaviors”
and therefore are more “susceptible to adherence difficulties” (Kondryn et al. 2011;
Taddeo et al. 2008). This view of adolescent invulnerability often leads practitioners to highlight potential consequences and at times even to stress the severest com- plications in the hopes of “waking the teen up” to the risks he really is facing. The problem is that there is little evidence in support of the invulnerability hypothesis of adolescent risk-taking (Reyna and Farley 2006), and highlighting consequences has been shown to often have the opposite of the intended effect, as discussed further below.
Moreover, the evidence suggests that adolescents tend to overestimate their vul- nerability to risk for many negative outcomes, such as HIV infection or getting lung cancer from smoking (Millstein and Halpern-Felsher 2002). At the same time, how- ever, they tend to underestimate the seriousness of the long-term consequences. As noted by Reyna and Farley (2006), “they think the risk is high, but the consequences are not that bad.”
Teenagers do often have what has been termed an optimistic bias, a tendency to believe that bad things are much more likely to happen to other people (Gerrard et al. 2008), and the optimistic bias is predictive of poorer adherence (e.g., Patino et al. 2005). However — and this is the crucial point—the optimistic bias is not spe- cific to adolescents. Instead, it appears to be a quite general and pervasive bias that characterizes people of all ages, not just adolescents (Fischhoff and Quadrel 1991;
Millstein and Halpern-Felsher 2002; Quadrel et al. 1993; Reyna and Farley 2006).
The relation between perceived vulnerability and health-risk behaviors is un- clear. Some research indicates that adolescents who are engaged in risky behavior such as smoking (Milam et al. 2000), drinking (Cohn et al. 1995), and high-risk sex (Murphy et al. 1998) are aware of the heightened risk but engage in those behaviors anyway (Reyna and Farley 2006). At the same time, other studies indicate that indi- viduals engaged in risky behavior underestimate the risk, as would be predicted by rational models of behavior like the health-belief model (Reyna and Farley 2006).
Consistent with this, low health literacy is associated with greater general risk-tak- ing behavior in adolescents (DeWalt and Hink 2009).
It may be that these conflicting findings reflect the behavior of different types of risk-takers; alternately, among youth engaging in risky behavior, some may have or observe negative outcomes whereas others may not, leading to different risk perceptions over time. There is evidence that risk perceptions are highest among younger adolescents, and that older youth who have engaged in risky behavior without significant consequences may downgrade their risk perceptions accord- ingly (Halpern-Felsher et al. 2001; Reyna and Farley 2006). For youth with chronic illness, this would argue against allowing them too much freedom to “learn from their mistakes” (Sawyer and Aroni 2005), as they might instead learn that the odds of something bad happening from any single behavior are relatively low, although the combined odds approach certainty when they engage in behavior recurrently (Reyna and Farley 2006). In support of this, data suggest that when adolescents have positive experiences with behaviors such as drinking alcohol they are more likely to engage in that behavior in the future (Goldberg et al. 2002).
Clinical implications of the cognitive findings The findings presented above lead to a counter-intuitive conclusion. If youth tend to weigh potential costs against the benefits of engaging in risky behaviors, then presenting them with more factual information about risk can actually backfire. As noted above, teens overestimate many risks (Millstein and Halpern-Felsher 2002; Reyna and Adam 2003), so pre- senting them with more accurate information might lead them to think that the risk is not so high after all.
Consider a recent brochure about marijuana aimed at teens titled “Drugs: Shatter the Myths” (NIH Publication No. 13-7589, 2013) which begins with the question,
“Is marijuana addictive?” It then answers: “Yes. The chances of becoming addicted to marijuana or any drug are different for each person. For marijuana, around 1 in 11 people who use it become addicted. Could you be that one?” Reyna’s research suggests that many adolescents would take 1 in 11 as good odds, and be more likely to smoke marijuana after reading this brochure, rather than less. (Better is a later page on nicotine, which presents the simple fact: “Most people who start smoking in their teens become regular smokers before they’re 18.”).
Indeed, there is now good evidence that educational programs that stress risk to teens don’t work, and in some cases they cause harm. For example, studies of Drug Abuse and Resistance Education (DARE) Programs have shown either null results or iatrogenic effects, with participating children sometimes showing an increase in alcohol and drug use (Lilienfeld 2007).
Of course, adolescents do need to be provided with appropriate information about health risks and benefits. The work of Reyna and her colleagues suggests that this information should not be presented in terms of relative odds, which reinforces teens’ tendency to weigh relative risks and benefits, but in terms of underlying gist.
As noted by Reyna and Rivers (2008), Gibbons and Gerrard (1997) reach a similar conclusion via a different route. They argue that most health-risk behaviors have images associated with them (a classic example being the Marlboro Man), that these images are highly accessible, and that they influence teens’ behavior. Specifically, the more favorable the image, the likelier it will be that a youth will engage in that behavior (Gibbons et al. 2003). This model has substantial empirical support
84 6 Adherence in Adolescence
(Gerrard et al. 2008). Based on these and related findings, Reyna and Rivers (2008) suggest that an important, empirically-supported way to reduce teen risk is to “en- courage the development of positive prototypes (gists) or images of healthy be- haviors and negative images of unhealthy behaviors using visual depictions, films, novels, serial dramas and other emotionally evocative media.”
It should be noted that is possible for images to backfire, especially if they focus solely on risks to the exclusion of benefits. Pictorial warnings about the dangerous of smoking are the paradigmatic example. There is some evidence that graphic, fear-inducing pictures of the negative effects of smoking can result in avoidance of the message or in “psychological reactance” (Brehm 1966), a motivational state in which a person reacts against a message to preserve a sense of freedom and au- tonomy (see, for example, Erceg-Hurn and Steed 2011). However, the majority of studies show that even extremely graphic negative images are powerful motivators for change among youth as well as adult (Hammond 2011).