Evidence-Based Reviews

The placebo effect in psychiatric practice

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“It is a mystery how a ubiquitous treatment used since antiquity was unknown, unnamed, and unidentified until recently. It is even more remarkable because this is the only treatment common to all societies and cultures.”1

The treatment discussed above is not a specific pill, surgery, plant, or herb. Rather, the authors are referring to placebo. Indeed, the history of medical treatment is largely a chronicle of placebos. When subjected to scientific scrutiny, the overwhelming majority of treatments have turned out to be devoid of intrinsic therapeutic value; they derived their benefits from the placebo effect. Despite these benefits, the term “placebo” comes with unfortunate baggage. Latin for “I shall please,” it is the first word of the Christian vespers for the dead. In the 12th century these vespers were commonly referred to as placebos. By the 1300s, the term had become secular and pejorative, suggesting a flatterer or sycophant. When the word entered medical terminology in the late 18th century, the negative connotation stuck. A placebo was defined as a medicine given to please patients rather than to benefit them. In the modern era, the lack of pharmacologic activity became part of the definition as well.

The word placebo brings with it connotations of deception, fakery, and ineffectiveness. But one of the things about placebos that contribute mightily to the health care community’s aversion toward them is, in fact, their effectiveness. They bring relief across a wide range of medical conditions.2 In doing so, placebos impugn the value of our most cherished remedies, hamper the development of new therapeutics, and threaten our livelihoods as health professionals.3

Placebos often are conceptualized as any treatment that lacks intrinsic therapeutic value, such as sugar pills. But looking at what placebo treatment actually entails, both in placebo-controlled treatment trials and in clinical settings, suggests a more comprehensive definition. Placebos encompass all the elements common to any treatment or healing situation. These include a recognized healer, evaluation, diagnosis, prognosis, plausible treatment, and most importantly, the expectation that one will recover. Along these lines, the placebo response can be thought of as the response to the common elements of the treatment or healing situation.3

Research regarding the placebo effect has mushroomed in the past 2 decades. Over this time, we have learned a good deal about both the mechanisms underlying the placebo effect and how the placebo effect can be applied to enhance the benefit of conventional treatment. Brain imaging technology has revealed that when placebo treatment alleviates pain, Parkinson’s disease, and depression, brain changes occur that are similar to those observed with active pharma­cologic treatment.4,5 Recent studies also show that deliberate, open (nondeceptive) use of placebo can improve the symptoms of several conditions, including depression, pain, and irritable bowel syndrome.6 Furthermore, intermittent substitution of placebo pills for pharmacologically active treatment in a conditioning paradigm can be as effective as the “real” treatment.7 Also, research over the past decade has verified that certain common features of the treatment situation, particularly the quality of the doctor–patient encounter, contribute to the placebo response and have a demonstrable impact on the outcome of treatment.8 Clearly, the placebo effect has gone from being simply a nuisance that interferes with the evaluation of new treatments to a variable worthy of study and application in its own right. Although, for the most part, clinical practice has not kept up with these advances.

Placebos seem to have their greatest impact on the subjective symptoms of disease—pain, distress, and discouragement. It should come as no surprise, then, that placebos are particularly effective in certain psychiatric conditions. In some forms of anxiety and depressive disorders, for example, distress is the illness, and placebos reliably bring relief. Patients with panic disorder, mild to moderate depression, or generalized anxiety disorder get almost as much relief with placebo as they do with conventional treatment (about one-half improve with placebo).9-11 But <20% of those with obsessive-compulsive disorder improve with placebo, and placebo response rates are also low in patients with schizophrenia or dementia. Mania, attention-deficit/hyperactivity disorder (ADHD), and severe depression fall somewhere in the middle.3

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