Taking Psychology with You

Should You Have Genetic Testing?

Imagine that you have been feeling depressed and you go to a clinical psychologist for help. The psychologist interviews you, gives you a battery of psychological tests, lets you talk about your problems—and then has your blood drawn to check your DNA, to find out if you have a genetic predisposition for depression.

You have your blood drawn? Right now, this scenario is hypothetical, but perhaps not for long. Genetic testing can already identify DNA markers that indicate an increased risk of developing many physical diseases. Eventually, the same may be true for learning disabilities and emotional disorders. Testing now relies on genome-wide associations, but many geneticists expect whole-genome mapping to become a standard tool in the coming years. Although it took the Human Genome Project several years and billions of dollars to produce the first map of the human genome, a map of an individual's genome can now be produced in hours for just several thousand dollars, and the price is expected to drop much further. Francis Collins (2010), former director of the Human Genome Project, believes that whole-genome mapping is likely to become part of newborn screening in just a few years.

Genetic testing can reveal information that a person may or may not want to know. What’s your view of the pros and cons of such testing?

The growing popularity of genetic testing raises many questions. Such testing is beginning to provide an invaluable tool for predicting how a person will respond to a particular medication, and can also help scientists hone in on the causes of specific medical conditions. But except for diseases like Huntington's, which is caused by a single variant, a genetic test cannot tell you that you will get a disease; it can only tell you your risk relative to that in the general population. You could have double the usual risk, yet that risk could still be quite low—a jump from 1.5 percent to 3 percent is “double” the risk, but still extremely rare.

Would you want to be tested for a gene that moderately increases the risk of developing Alzheimer's disease, which affects many people as they age and is currently not curable? What about a disorder that might or might not become symptomatic, or one that could be easily treated? What if the disorder in question were depression? And how would you feel about being tested for a gene that indicates a slight increase in the risk of dying early? Would you want to know so that you could plan accordingly or make lifestyle changes, or would you rather let life, and death, take their own course?

Consider, too, some questions raised by prenatal genetic screening. Pregnant women and their partners are often tested to determine whether they are carrying genes that are likely to condemn their child to a fatal or painful disease. When the test results are positive, many choose to abort the pregnancy. But what if you could be tested for a gene that slightly increases your future child's risk of developing schizophrenia, drug addiction, or autism? Or growing up gay? Or being short? Or having a reading disability? If you had that information, what would you do with it (Khan et al., 2014)?

In coming years, as noninvasive methods of genetic testing such as blood tests and saliva analysis become widespread, all of us are going to have to think long and hard about such questions. You can use information from this chapter to evaluate the pros and cons of such testing for yourself or a family member. Here are some things to keep in mind:

Genes are not destiny. You learned in this chapter that most human traits are influenced by many genes interacting with many environmental factors. As a result, genes do not determine most traits and diseases; they simply affect the probability of developing a particular trait or disease. That is why knowing that you have markers for one or two genes that may contribute slightly or moderately to a trait or disorder does not necessarily tell you much in practical terms.
Genetic information could be used to discriminate against you. Critics of genetic testing worry that insurance companies will refuse coverage to adults and children who are currently healthy but whose DNA reveals that they have some genetic predisposition for developing a physical or psychological disorder later in life. Employers may also be reluctant to hire them. Some countries—such as the United States, the United Kingdom, Finland, and New Zealand—have laws, codes, or other guidelines to protect the privacy of genetic information. But some bioethicists worry that these laws are not strong enough and are not keeping up with the rapid advances in genetic testing.
Knowing your genetic risk does not necessarily tell you what to do about it. If your child has a physical disorder called phenylketonuria (PKU), which prevents the body from assimilating protein and causes mental retardation, the solution is obvious: Limit the intake of protein. (Children in most developed countries are screened for PKU at birth.) But in the case of behavioral, cognitive, or emotional problems, the answer may not be so straightforward. Often we simply don't yet know how to prevent problems that have a genetic component. Or many possible approaches exist and we don't know which one is best.
Genetic testing can be liberating or stigmatizing. Knowing that a condition or trait is “not your fault” may help you live with it. On the positive side, knowing that your child's autism is genetic and not caused by bad parenting or vaccination can keep you from feeling unnecessary guilt. On the negative side, genetic testing can activate prejudices against anyone with “undesirable” looks or abilities. In the past, such prejudices led to horrifying efforts to “improve” the species through forced sterilization of low-IQ people—and not only in Nazi Germany. From the beginning of the 20th century until the mid-1960s, thousands of mentally ill and developmentally delayed Americans were sterilized against their will (Bruinius, 2006).
Defenders of genetic testing answer that the goal of prenatal screening is not to improve the human species; it is to relieve the suffering of parents and children, and therefore prospective parents should not feel guilty for taking advantage of this technology (Cowan, 2008). But to some social critics, prenatal testing for run-of-the-mill human qualities reflects a view of children as products to be perfected instead of as individuals to be appreciated for who they are (Sandel, 2007).
Knowing about a genetic disposition can create a premature diagnosis or a self-fulfilling prophecy. If parents and school officials know that a child is at risk of developing a learning disorder, they may treat the child as cognitively impaired even though the child has not shown any signs of a problem. If they know that a child carries a gene associated with an increased risk of aggressiveness, they may come to think of the child as a “bad seed” even if the child has never had behavioral problems. If a person is aware of having a genetic predisposition toward depression, he or she may not develop the skills to cope with setbacks, deciding incorrectly that “There's nothing I can do.”

We hope we have given you some things to think about. Under what circumstances, if any, would you want to undergo a genetic test, and why? And how might this information change your life?