Genetic Testing and Stress

Overview of Genetic Testing. The knowledge generated by the Human Genome Project has already started to revolutionize our understanding of health and illness. It is now possible to identify people who have a genetic predisposition to an increasing number and variety of diseases. This knowledge offers great potential for disease prevention, developing more effective treatments, and, indeed, the hope of treating diseases that are currently incurable.

This new understanding of the human genome also brings with it a whole host of ethical, social, and psychological dilemmas. Although genetic testing for certain conditions means that those at risk can reduce their chances of developing the disease, for other conditions genetic testing means that some people have to live with the knowledge that they are almost certain to develop an incurable disease.

Genetic testing has implications for decisions about whether to have children and who to have them with, what to do if a fetus is known to have a genetic disease, and whether individuals will be discriminated against when seeking employment or insurance.

In this article, we focus on the role of stress in predictive genetic testing. This is because most of the well-conducted psychological evaluations conducted to date that assess stress using validated measures concerned predictive genetic testing. Also, in other forms of genetic testing, such as carrier testing, the psychological issues primarily concern decisions about pregnancy and childbirth.

Carrier testing is concerned with identifying people who have a copy of a deleterious mutation for an autosomal recessive condition. These people do not develop the disease in question, but if they have children with someone who is also a carrier of the mutation, each child has a 25% chance of having the condition.

Examples of these conditions are Tay-Sachs disease, sickle cell disease, and cystic fibrosis. Predictive genetic testing is concerned with identifying people who are at high risk of developing the disease themselves. All of the predictive genetic tests currently available raise different medical, psychological, and ethical issues.

One of the first genetic tests developed was for Huntington disease, an incurable neurodegenerative condition that typically develops in middle age or later life. People who carry the mutation definitely develop Huntington disease at some point, and those who do not carry the mutation definitely do not develop the disease.

There is understandable concern that offering at-risk families genetic testing will constitute an enormous psychological burden for those who test positive. There are a number of exemplary longitudinal studies conducted worldwide to evaluate the consequences of genetic testing for these families. There are also an increasing number of psychological evaluations of genetic testing for a predisposition to cancer, particularly breast and ovarian cancer but also forms of colon cancer. In these cases, the psychological issues include the stress that may be associated with being found to be a carrier of a predisposing mutation and behavioral responses to genetic risk information.

These behaviors include whether people adhere to recommendations about surveillance to detect possible cancers and also decisions about whether to have surgery to remove tissues likely to be affected prior to the development of any cancer (called prophylactic surgery). In the case of an inherited predisposition to cancer, being a carrier of a mutation increases the cancer risk considerably, typically making the likeliness of developing cancer 60-80%, but it does not make cancer inevitable.

In addition, those found not to carry the genetic mutation still have at least the same risk as the general population of developing cancer, which means it is important that these people do not believe they are not at risk. For other diseases, genetic testing is still in its infancy. For example, it is possible to offer predictive genetic testing for the predisposition to coronary heart disease and Alzheimer’s disease.

In the case of coronary heart disease, predictive genetic testing can be offered for familial hypercholesterolemia, an inherited predisposition to raised cholesterol levels. Because the treatment for this condition, in the form of cholesterol-lowering statin medication, is very effective, the psychological issues raised pertain particularly to preventative behavior, that is, whether those identified adhere to medication regimens and engage in other risk-reducing behaviors such as eating a low-fat diet and not smoking.

Like Huntington disease, Alzheimer’s disease is not curable at present. However, genetic testing for Alzheimer’s indicates whether an individual has an increased risk for the disease rather than providing the information that an individual definitely will or will not go on to develop it. In this case, it is necessary for those undergoing testing to understand quite complicated probabilities.

Genetic testing programs differ in how they are organized. In some cases, everyone within a particular population may be offered genetic testing. Such population-based screening programs are most common for detecting carriers of recessive genes and for the prenatal and neonatal screening of infants. More common among predictive genetic testing programs is some form of cascade screening.

These programs start with an individual who either has the disease or is at known risk (called the proband) and, if a deleterious mutation is identified in this individual, genetic testing is then offered to other biological relatives.

All these factors have an impact on the emotional state, risk perceptions, and expectations of those offered genetic testing and receiving the results of genetic tests. An interactional model of stress is widely accepted within the stress community, whereby stress is conceptualized as a process involving an interaction of individuals and their environment.

One such example is the transactional model of stress and coping proposed by Lazarus and Folkman in the 1980s. Using this framework, we address three main questions with respect to genetic testing: does stress influence the decision to have a genetic test, is receiving the results of genetic testing stressful, and does genetic testing influence secondary appraisal processes and coping strategies? Each of these issues is now considered in turn.