Genetic susceptibility testing from a stress and coping perspective

Abstract

Four theories of health behavior and of stress and coping are reviewed for their ability to illuminate interest in uptake and outcomes of genetic testing for adult-onset diseases. These theories are the Health Belief Model, the Theory of Planned Behavior (TPB), the Common Sense Model of Self-regulation (CSM), and the Transactional Model of Stress and Coping (TMSC). Basic concepts of each theory are discussed, followed by evidence from the literature supporting the relevance of these concepts to the understanding of genetic testing for four adult-onset diseases: Huntington's disease, Alzheimer's disease, hereditary breast/ovarian cancer, and hereditary colorectal cancer. Emphasis is placed on the finding that a decision to undergo genetic testing may be considered as a way to cope with both the cognitive and affective concerns that arise from living at increased risk of developing a disease in the future. The potential value of genetic testing for reducing uncertainty about and gaining a sense of control over one's risk of developing a chronic disease is highlighted. We argue that theories which focus on stress and coping provide a useful framework for future studies of genetic testing decisions for adult-onset disease risk.

Introduction

In their primer on genomic medicine, Guttmacher and Collins (2002) write that “we have recently entered a transition period in which specific genetic knowledge is becoming critical to the delivery of effective health care for everyone” (p. 1512). By studying the entire set of human genes, scientists have begun to identify genes associated with complex disorders such as diabetes, certain cancers, and Alzheimer's disease. In a recent article in Social Science & Medicine, Wang, Gonzalez, and Merajver (2004) examined the goals of genetic testing and counseling services and proposed a framework for evaluating the outcomes of those services. This paper furthers the discussion about enhancing understanding of genetic testing decision-making by framing cognitive and affective motivations for undergoing testing.

Theories about how individuals respond to a threat to their health, such as the potential for developing a life-threatening condition, and theories about why individuals perform certain health behaviors, such as availing themselves of screening tests, are relevant to genetic testing research. Although only a portion of genetic testing studies have explicitly based their research designs on psychological theories, domains common to theories of health behavior and stress and coping have been examined in many studies and have emerged as important predictors of who utilizes genetic testing and how individuals respond to their results. Several researchers have called for a more systematic application of health psychology theories to the design and interpretation of studies of genetic testing (Croyle, Achilles, & Lerman, 1997). This article explores those health psychology theories most relevant to the genetic testing experience and argues for understanding interest in, uptake, and outcomes of genetic testing from a stress and coping perspective and for using stress and coping theory to design research about these issues in the future.

Two neurodegenerative diseases (Huntington's and Alzheimer's) and two cancers (breast/ovarian and colorectal) are the foci of this discussion. Highlights from empirical studies of genetic testing for these four diseases are reviewed and examined from the perspective of two theories of health behavior (the Health Belief Model (HBM) and the Theory of Planned Behavior (TPB)) and two theories of stress and coping (the Common Sense Model of Self-regulation (CSM) and the Transactional Model of Stress and Coping (TMSC)). These specific theories were selected because each has been explicitly employed in two or more empirical studies of genetic testing for adult-onset conditions. Studies of interest in genetic testing comprise the bulk of the empirical research reviewed. Where available, uptake and outcome studies are included.

The characteristics of Huntington's disease, Alzheimer's disease, hereditary breast/ovarian cancer, and hereditary colorectal cancer create interesting opportunities for comparison of their associated genetic testing experiences. The spectrum of lifetime risk of future disease in those receiving positive results using currently available genetic tests ranges from 100% for Huntington's disease (Evers-Kiebooms & Decruyenaere, 1998), 60–90% for breast/ovarian cancer (Gelehrter, Collins, & Ginsburg, 1998), 80–100% for colorectal cancer (Chung & Rustgi, 2003), to approximately 50% for Alzheimer's disease (Cupples et al., 2004). Only those without the genetic mutation associated with Huntington's disease are left with no residual risk of future disease. Individuals with negative genetic testing results for the other conditions still face the general population risks for those diseases. Similarly, methods available to at-risk persons for screening for each disease range from accurate (colonoscopy for colorectal cancer) to controversial (mammography for breast cancer) to crude (mental status examinations for Alzheimer's disease).

Interventions available to prevent future disease vary as well. Colorectal cancer and breast/ovarian cancer can be largely prevented by radical surgeries to remove the organ at-risk. However, these surgeries come with their own repercussions, and in the case of mastectomies and oophorectomies are not entirely preventive (Rebbeck et al., 2004). Conversely, there are no known preventions for Huntington's disease and only preliminary recommendations about diet, mental, and physical activity for prevention of Alzheimer's disease. Finally, Huntington's and Alzheimer's diseases involve the loss of cognition, while breast/ovarian and colorectal cancers primarily cause physical suffering. Certainly each disease can produce psychological pain associated with changes in one's state of health and ultimately one's own mortality. These common threats to health and well-being are doubtless part of the motivation for pursuit of genetic testing for adult-onset conditions.

Despite the differences amongst these four conditions, empirical studies have revealed remarkably similar characteristics describing individuals interested in and choosing to learn personal genetic risk information about their susceptibility to them. This suggests that there may be personal values and preferences, interacting with the characteristics of the specific diseases and the properties of their genetic tests, which are common to many individuals who decide to undergo genetic testing. Understanding components of this decision-making process and its outcomes helps to ensure informed choices about testing and “good” decisional outcomes by identifying opportunities for effective interventions. Through our examination of constructs from health psychology, we aim to provide a research framework for understanding those common characteristics that motivate interest and use of genetic testing as a way to cope with the threat of being at-risk for disease.