An at-home bipolar test, launched in February 2008 and sold over the Internet, is meant to be used with a doctor's evaluation to make a correct diagnosis of bipolar disorder more quickly.
"Sales continue to be brisk," says Kurt May, CEO and founder of Psynomics Inc., the San Diego-based company producing the $399 at-home test for bipolar disorder, the latest in an array of tests marketed to consumers who want to know their risk for various diseases.
But some mental health experts are skeptical about the test, saying that while its premise shows promise, more research about the genetic links to bipolar disorder is needed to back up the credibility of such tests.
On one point proponents and critics alike agree: The bipolar test doesn't tell users if they do or don't have the mental illness. Rather, it reveals whether their genetic makeup may put them at higher risk of having it -- or getting it.
The Bipolar Test: How It Works
The bipolar test, called Psynome, looks for two mutations in a gene, GRK3, associated with bipolar disorder. The test is based on the long-term work of John Kelsoe, MD, a board-certified psychiatrist and professor of psychiatry at the University of California San Diego, who is co-founder of the company and serves as executive vice president.
People who have either of the two gene mutations, are white, are of Northern European ancestry, and have a family history of bipolar disorder are three times more likely to have bipolar disorder themselves, according to the company web site. Research has not shown such an association for other ethnic groups, according to Psynomics.
"This test is different than others that are truly home tests," says Martin Schalling, MD, PhD, a professor of medical genetics at the Karolinska Institutet in Stockholm, Sweden, and a member of the scientific advisory board for Psynomics. "The results go to the treating physician."
Purchasers are mailed a "spit kit" and are instructed to deposit saliva into the kit's resealable container, then mail the saliva sample back to Psynomics.
A second genetic test is also available. It predicts a patient's likely response to serotonin-based drugs, the most widely prescribed class of psychiatric drug therapy today, according to the Psynomic web site. It also costs $399. If both tests are ordered together, the cost is $750.
Tests are analyzed at a lab regulated by the state and by federal standards under the Clinical Laboratory Improvement Amendments of 1988.
The saliva is tested for GRK3 mutations linked to bipolar disorder. The results are sent to the patient's doctor, who discusses them with the patient.
Home Bipolar Disorder Test: How Accurate?
Schalling says the bipolar test is very accurate in detecting the genetic variant. "This test can tell you almost 100% if you have the risk variant," he says.
But it isn't meant to be used in isolation. "The test is really no good on its own," Schalling says. "The test must be used in combination with family history and the clinical picture."
According to Psynomics, bipolar disorder is largely hereditary, with inherited factors perhaps explaining as much as 70% of the cases.
Although the results are accurate, a definite prediction of bipolar disorder remains elusive. "This is a test that works, but it does not provide a huge amount of power, a huge amount of certainty," Schalling says. As more discoveries are made about other genes that are important in predicting bipolar disorder, that power is expected to increase.
Diagnosing Bipolar Disorder
Bipolar disorder, also known as manic depression, is marked by mood shifts, and these shifts can be subtle or dramatic, making it difficult to diagnose the disorder. Generally, it is lifelong, with recurring episodes of mania and depression that can last from days to months, according to the National Institute of Mental Health.
Symptoms of mania can include:
- Increased activity or energy
- Severe irritability
- An overly good, very euphoric mood
- Inability to concentrate
- Lack of good judgment
- Need for very little sleep
- Inability to stay "on topic"
- Lavish spending
- Boost in sex drive
- Drinking too much alcohol or abusing drugs or sleep medications
- Aggressive or provocative behavior
Depression, the other "pole," can be marked by such symptoms as:
- Feelings of pessimism, sadness, anxiety, or emptiness
- Lack of interest in any activities that used to bring pleasure, including sex
- Fatigue or diminished energy
- Feelings of irritability or restlessness
- Sleep problems -- too much or too little
- Weight gain or loss (without trying to) and unusual appetite changes
- Suicidal thoughts or attempts
A diagnosis of mania or depression is made based on how many symptoms occur, how frequently, and for how long. Sometimes, the diagnosis is missed altogether; other times, it's mislabeled as simply clinical depression.
Typically, a doctor takes a careful history, noting the symptoms, and asks about family history.
Estimates of how many people have bipolar disorder vary widely. The National Institute of Mental Health estimates about 5.7 million Americans over age 18 are affected.
The Bipolar Test: Second Opinions
Mental health experts consulted about the new bipolar disorder tests say the science is not yet there.
"Based on everything we know, this science [behind the bipolar test] is not ready for prime time," says Tom Insel, MD, director of the National Institute of Mental Health. He doesn't rule out the possibility that within a few years and with more discoveries about the genetic roots of mental illness, some ''practical information of value'' might be gotten from these types of tests.
Of the genetic links, Insel says: "What has been found is an association with a common [genetic] variant that increases your risk of the illness. It confers a very slight increase in risk. But that is a long way from being able to use that single genetic association to make any practical clinical decision."
"They simply haven't proven an association," says Douglas F. Levinson, MD, the Walter E. Nichols, MD, Professor of Psychiatry at Stanford University School of Medicine. "These tests are based on data which are not considered statistically significant in the field of genetics as a whole," he says, adding that a person's best resource for diagnosing bipolar disorder is still a mental health professional.
Medical ethicist Arthur Caplan, PhD, agrees that the science isn't there yet. "I think we have companies rushing to take advantage of hype that genomics is ready to go and predict a wide variety of diseases," says Caplan, the Emanuel and Robert Hart Professor of Bioethics at the University of Pennsylvania, Philadelphia. "It's coming, but [it's] not there yet."
A more powerful predictor would be to ask a doctor to look at your family history in more detail, says Ken Duckworth, MD, medical director of the National Alliance on Mental Illness and assistant professor at Harvard Medical School. "I would pay that $399 for the best mood disorders consultant in your city. Ask me in five years and perhaps I would have a different take on this.
"We don't actually know enough about the brain to consider genetic testing to be definitive at this point for any mental illness," he says.
The test could have potential harm, says Clarence H. Braddock III, MD, MPH, associate professor of medicine and director of clinical ethics for the Stanford Center for Biomedical Ethics. For instance, a doctor might erroneously diagnose someone as bipolar based on the genetic test results. "There are a lot of consequences [associated with an incorrect diagnosis]," he says, such as medication costs and side effects and the social stigma associated with mental illness.
In a general statement addressing all at-home genetic tests, the Federal Trade Commission notes that "a healthy dose of skepticism may be the best prescription."
A Patient's Perspective
The home test wasn't available when Ross Szabo, now 29, was diagnosed with bipolar disorder at age 16. He probably wouldn't have taken advantage of the test, he tells WebMD, because his diagnosis, based on symptoms, was "pretty clear."
Whether consumers use the test or not, says Szabo, who works as director of youth outreach for the National Mental Health Awareness Campaign, "you can't look at the diagnosis as the end of the problem. It's really only the beginning. Finding the right diagnosis is important. Accepting that diagnosis is more important.''