This is a good question, but one that it very difficult to answer. It has been suggested, with only mild sarcasm, that it may be easier to do psychotherapy than it is to define it (London, 1986). In preparing this chapter we reviewed many suggested definitions of psychotherapy. And although we found many suitable candidates, the definition with which we felt most comfortable was one offered by John Norcross (1990, p. 218):
One might quibble with Norcross’s definition by, for example, challenging the meaning of some of the key terms and phrases. What exactly is meant by “interpersonal stances,” and who decides which “psychological principles” are “established” and which are not? But such an enterprise is not worth the time of the authors or the reader. The scope of “psychotherapy” is so broad that no single definition is likely to satisfy everyone. One count has the number of different psychotherapy techniques for adults at over 400 (Karuso, 1985, cited in Kazdin, 1994b). And psychotherapies for children and adolescents number over 200 (Kazdin, 1988). It is not only the number of psychotherapies that make the task of defining psychotherapy so challenging but also the diversity of approaches. Psychotherapy has been used to describe everything from primal screams (Janov, 1970) to biofeedback (Blanchard & Epstein, 1978). In light of the volume and heterogeneity of psychotherapies, it is not surprising that most definitions can be found lacking.