Most clinicians have heard of placebo-controlled studies, but how important are such studies, and what is a placebo? As a pharmacologist, I believe very few therapies, including those for chemical dependency, do not involve a placebo outcome.
Carlton K. Erickson, PhD
Technically, a placebo effect is the measurable, observable, or apparent improvement in health not attributable to treatment. A placebo (Latin for “I shall please”) is a medication or treatment believed by its administrator to be inert or innocuous. Placebos may be sugar pills, starch pills, or saltwater injections. “Fake” psychotherapy (for example, untrained counseling with an air of credibility) is also considered a placebo-when it has some effect on the patient.
Researchers give placebos to human subjects as a “control” against an active treatment to determine the treatment's actual effectiveness. Why an inert substance or fake therapy would be effective is not known. Some believe the suggestion of an effect is the cause of the placebo's action, while others believe an administrator's attention to the person is responsible. Placebo responses have been as high as 30% in some studies.
Placebo response is apparently not related to the individual's intelligence, gender, race, beliefs, or age. In fact, a placebo responder in a pain-relief study may not be a placebo responder in an antidepressant study. Hypnosis, acupuncture, herbal remedies, and other “alternative therapies” may involve a significant placebo effect, but relatively few placebo-controlled studies have been carried out on such therapies.
A placebo-controlled study in science is believed to be one of the most powerful experimental studies, since a group of patients receiving an inert pill that looks and is administered exactly like an active pill will exhibit some positive effect. In a study of an antidepressant that is effective in 50% of depressed patients, if there is a positive placebo effect in 30% of the patients, the actual effectiveness of the antidepressant will be reported as 20%.
Even the way the medication is administered is critical. If a nurse knows that the patient is receiving a placebo, any suggestion or body language that tips the patient to what is being given can affect the outcome. This is the reason for “double-blind” studies in which neither the subject nor the administrator can be aware of whether a placebo or active medication is being given.
Inactive treatments and the environment in which they are given are so powerful that they can even have negative effects on the patient. This is called a “nocebo” (Latin for “I shall harm”).
Applicability to addiction
Is there an element of placebo response in the treatment of substance problems? Of course. Psychologists call this an “expectancy effect,” and the attitude, demeanor, experience, and charisma of a counselor can clearly add to or subtract from a client's total experience in treatment for drug abuse or dependence. Unfortunately, placebo-controlled studies are not as prevalent in chemical dependence treatment as they are for psychiatric medication therapies.
Yet the large federally funded Project MATCH multisite study of alcohol treatment clearly showed effects that were influenced by the experience of counselors in the study. Other studies are showing that simply assessing a client for abuse or dependence can produce a degree of positive outcome. Is it any wonder that there are many “therapies” for drug problems in our field that seem to help clients, even though there are no scientific studies of them?
Does the production of “addiction” to drugs have a placebo component? If anything, it is small. Chemical dependence is clearly a pathology of the brain's mesolimbic dopamine system, which probably is not influenced by a person's expectations of becoming “addicted.” But the treatment of a chemically dependent person obviously involves some degree of placebo effect, whether the treatment is counseling, 12-Step therapy, or anticraving medications. Sorting out the mostly placebo treatments for chemical dependence from the more powerful and reliable therapies constitutes one of our biggest challenges.
Carlton K. Erickson, PhD, is Director of the Addiction Science Research and Education Center at the University of Texas at Austin's College of Pharmacy.
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- de la Fuente-Fernandez R, Schulzer M, Stoessl AJ. The placebo effect in neurological disorders. Lancet Neurol 2002; 1:85-91.