The National Center for Complementary and Alternative Medicine (NCCAM) defines complementary and alternative medicine as "a group of diverse medical and health-care systems, practice and products that are not presently considered to be part of conventional medicine."

Of course, what qualifies as "in" or "out" of mainstream medicine is not always clear, says Ohio State University psychology professor Catherine Stoney, PhD, who studies CAM therapies. For example, cognitive-behavior therapy for depression was once considered alternative medicine but has since moved into mainstream practice. On the other hand, relaxation treatment for hypertension or hypnosis for pain control is often considered outside of the mainstream, she adds.

A goal of CAM researchers is to identify effective therapies and strategies and move them into the mainstream, says Alan Leshner, PhD, a member of the National Advisory Council for Complementary and Alternative Medicine and CEO of the American Association for the Advancement of Science.

"Today's complementary and alternative medicine is tomorrow's mainstream, but first it must be met with rigorous scientific evaluation," says Leshner, a former director of the National Institute on Drug Abuse at the National Institutes of Health.

In the meantime, psychologists and other health practitioners can seek information on the efficacy of existing CAM practices by visiting the NCCAM Web site at or calling the NCCAM Clearinghouse at (888) 644-6226, advises psychologist and NCCAM Deputy Director Margaret Chesney, PhD. Another resource that's helpful in distinguishing legitimate from flaky alternative treatments is the Cochrane Collaboration (, which publishes results of randomized trials of various CAM therapies.

Chesney also encourages psychologists to ask patients if they use CAM therapies--especially since such strategies may affect treatment outcomes. For example, patients may take vitamin A believing it will help improve skin appearance, but too much vitamin A may cause mental health disturbances, fatigue or agitation, Chesney notes.