Potential clients and students of psychology often ask a very good question: “Which therapy works best or, at least, does one work better than others?” Unfortunately, the answer, at least according to a famous meta-analysis (Smith et al., 1977, 1980), may be that all therapeutic approaches are equally effective (or ineffective, depending on how one interprets the data). This is due to a variety of factors known as nonspeciﬁc effects of treatment— nonspeciﬁc because they occur in all therapeutic settings, rather than being speciﬁc to a particular type.
Although all therapies have advocates who claim that theirs is clearly the superior product, Smith’s comparison yielded no winner. Furthermore, the type of therapy, the context (individual or group), and the level of training and experience of the therapist were all equally useless in discerning relative effectiveness of therapies. Note, however, that this analysis was based on studies in which clients in treatment were compared to a control group of people who were not undergoing treatment. The real conclusion to be drawn, therefore, is that receiving treatment is generally more likely to be helpful than not receiving treatment.
These nonspeciﬁc effects involve elements that are common to all therapeutic settings. These include, but are not limited to, the following:
- Hope for improvement—Simply seeking out therapy indicates an expectation that improvement is possible, and so the person who seeks out treatment is motivated by hope in a way that somebody who does not seek it out clearly is not. In other words, they expect to get better, and so they do.
- A trusting relationship with a caring person—In seeking therapy, the client is establishing a trusting relationship with another person who also believes improvement can happen, and who is dedicated to helping the client. The mere fact that someone is paying attention to the client may produce improvement.
- Most illnesses, both mental and physical, are self-limiting—When a person has a cold and gets proper medical treatment, that person may feel much better within a week. Another person who does not seek treatment, however, may take as long as seven days to improve. Most physical illnesses go away on their own. What is missing from many discussions of Smith and his colleagues’ ﬁndings, however, is that most of the untreated people in those studies of different therapies also got better over time.
It is because these effects are well known that studies of treatment efﬁcacy must be designed in such a way as to distinguish real treatment effects from nonspeciﬁc effects.
One way that this is accomplished is through the use of placebos. A placebo is simply a fake treatment. In medical studies, a placebo is frequently a pill containing only an inert substance, often sugar, rather than any medically active ingredient. In this way, people receiving the actual drug can be compared to people who have experienced all aspects of treatment except for the drug. In psychological treatment studies, placebo treatments are often used in which the placebo control group is treated in the same way as the group receiving the experimental treatment except that they do not receive the elements of the treatment that are expected to actually produce improvement. One example of this would be a recent study of eye movement desensitization and reprocessing (EMDR). The control group received treatment without the eye movements that give the therapy its name. A common ﬁnding in such studies is that participants receiving a placebo almost always show signiﬁcantly greater improvement than untreated control subjects. This well documented pattern of results is known as the placebo effect and is clearly due primarily to nonspeciﬁc effects.
- Perlman, L. M. “Nonspeciﬁc, Unintended, and Serendipitous Effects in Psychotherapy.” Professional Psychology: Research & Practice, 32(3) (2001): 283–289;
- Smith, M. L., and Glass, G. V. “Meta-Analysis of Psychotherapy Outcome Studies.” American Psychologist, 32(9) (1977): 752–760;
- Smith, M. L., Glass, G. V., and Miller, R. L. The Beneﬁts of Psychotherapy. Baltimore: Johns Hopkins, 1980.