Even when exposed to severe stressors, most people adapt reasonably well, without experiencing toxic stress or going on to develop more serious outcomes such as post traumatic stress disorder (PTSD). Diathesis/stress models posit that certain intrinsic factors (diatheses) predispose someone to greater or lesser vulnerability to stressful situations (Zuckerman 1999). Having a genetic predisposition to depression would be one example. Early exposure to toxic stress is another critically important contributor to stress vulnerability (Anda et al. 2006). As we discussed earlier, chronic illness can be a significant source of stress that can be experienced as traumatic (at diagnosis) and unremitting (as in the case of illnesses like diabetes that require daily management and allow no “holidays”).

In many cases even severe stressors can be modulated by parental warmth and support, serving to “detoxify” extreme stress to some degree (National Scientific Council on the Developing Child 2004); but when support is lacking, vulnerability to the affects of stress can be quite high. The role of parents in moderating stress further highlights the importance of parenting to the adjustment (and ultimately adherence behaviors) of children with chronic illness, as will be discussed further below.

The impact of toxic stress also falls especially heavily on the poor and minorities, contributing to disparities in development, educational and occupational attainment, and both mental and physical health (Shonkoff 2010). We believe that toxic stress is also likely an important contributor to disparities in chronic illness management among impoverished and minority children. Toxic stress could potentially affect adherence in multiple ways.

Poor chronic illness control in turn can make adherence much more challenging (Bender and Klinnert 1998; DiMatteo et al. 2007). Patients can end up feeling helpless and hopeless when faced with unresponsive and unremitting symptoms and eventually “give up” on attempts to manage their illness (Polonsky 1996). As suggested by DiMatteo et al. (2007), “Establishing medication and treatment routines central to the management of complex regimens, and attempting to live normal gratifying lives despite the demands of serious disease, can be very difficult when health status becomes increasingly poor.”

In addition to mental health and behavioral concerns, toxic stress is also associated with cognitive difficulties that can influence adherence. Early in life, toxic stress affects brain development and is believed to be a potent contributor to disparities in learning and cognitive functioning (Baker et al. 2013; Pechtel and Pizzagalli 2010; Shonkoff 2010); including significant memory impairment (Anda et al. 2006) and executive dysfunction (Bos et al. 2009), abilities which are integral to successful illness management (Duke and Harris 2014; Soutor et al. 2004). Memory impairment is especially notable, given that the most common reason offered for medication nonadherence is forgetting (e.g., Buchanan et al. 2012).

The research reviewed above provides a strong albeit circumstantial case for the effect of toxic stress on pediatric adherence. However, there is also some direct evidence that toxic stress can impair adherence. Stressful life events have been found to be associated with lower adherence in children with HIV (Williams et al. 2006), while a history of childhood abuse is a very strong predictor of nonadherence and graft failure in liver transplant patients (Lurie et al. 2000; Shemesh et al. 2007).

In a classic article on the effects of poverty on children’s psychological functioning, Evans (2004) wrote:

Psychologists are aware of the multiple disadvantages accompanying low income in America. Yet the search for explanatory processes of poverty’s impacts on children has focused almost exclusively on psychosocial characteristics within the family, particularly negative parenting.

He rightly goes on to criticize this focus as too limited, suggesting that it ignores the cumulative exposure to multiple stressors and environmental risk factors that poor children routinely face. While we agree that parenting is not the cause of health disparities —that parenting is not the problem—it is unquestionably a critical part of the solution.

Healthy relationships provide the strongest buffers for childhood adversity (National Scientific Council on the Developing Child 2004). Positive parenting—defined as parenting that is supportive and warm—is strongly associated with children’s development, behavioral functioning, and psychological well-being (O. S. Schwartz et al. 2013). As we discuss in Chap. 7, positive parenting is also associated with better regimen adherence, although what constitutes effective parenting changes at different ages.

Finally, it also should be noted that impoverished children and their families are more likely to have multiple risk factors that can interact to further complicated adherence. In one study (Schwartz et al. 2011), children with type 1 diabetes and behavior problems who came from single-parent families (but not those living in dual parent households) had an almost six-fold increase in risk for a diabetes-related emergency room visit post-diagnosis. It may simply be too difficult for single parents to gain compliance from behaviorally difficult children in the face of all of the other competing demands vying for their attention. This finding reinforces two points: that parent-child interactions are a critical determinant of adherence and illness control, and that these interactions (and their outcomes) are strongly influenced by broader macrosystem factors (Bronfenbrenner 1979). To the latter point, in another study examining risk factors in children with type 1 diabetes (Schwartz et al. 2014), patients at moderate risk for developing poor glycemic control had a high incidence of demographic risk factors only, whereas high risk patients had both demographic and psychosocial risk (Fig. 8.2.).

Due to the persistence of poverty-related disparities in healthcare utilization, parent education, and health literacy , many clinicians despair of helping their low income patients when problems with adherence emerge. It simply feels like the problems are too big, and too much out of their hands. Poverty is first and foremost a societal and political issue, and progress in addressing poverty-related health disparities in the U.S. has been limited. There are some very promising changes occurring, such as the move to the medical home model, that have the potential to transform healthcare for the poor. Yet the effects of poverty are likely to remain potent for a long time to come.

However, there is a growing recognition that pediatricians and other clinicians do have an important role to play in identifying and managing toxic stress in their patients. The American Academy of Pediatrics has identified toxic stress as a priority area (Garner et al. 2012), and a work group is currently developing guidelines for prevention, screening, and treatment, and for parent education. The AAP recommends public outreach for preventive efforts, in-office screening, and collaborating with networks of other professionals (social workers, psychologists) in treatment. Importantly (we believe critically), the guidelines also stress promotion of the role of positive parenting :