Handbook of Psychotherapy and Behavior Change: The Handbook of Psychotherapy and Behavior Change is perhaps the most important compendium of psychotherapy research covering a large number of research areas. The Handbook is updated approximately every 10 years, and the most recent 6th edition was published in January 2013. In the coming months I will review one chapter a month in addition to commenting on psychotherapy research articles. Book chapters have more restrictive copy right rules about distributing content, so I will not provide author email addresses for these chapters. If you are interested, you can view the table of contents on Amazon.
Lambert, M.J. (2013). The efficacy and effectiveness of psychotherapy. In M.J. Lambert (Ed.) Bergin and Garfield’s handbook of psychotherapy and behaviour change (6th ed.), pp169-218. Hoboken, N.J.: Wiley.
This comprehensive chapter in the Handbook reviews research on the efficacy and effectiveness of psychotherapy. Lambert’s reviews focus on meta-analyses, which is a way of summarizing effect sizes in a research area. The bottom line is that psychotherapy is effective so that 40% to 60% of clients show substantial benefit in controlled research trials, though the effect is likely smaller in routine practice. Concurrently, a consistent proportion of adults (5% to 10%) deteriorate during psychotherapy. Patients who receive formal treatment are better off than those who receive no treatment, and bona fide treatments are superior to control conditions that provide only some aspects of effective treatment. When psychotherapy is offered by skilful therapists, on average clients experience appreciable gains and return to normal functioning. Fifty percent of patients achieve clinically significant gains after 8 sessions, and 50% achieve recovery after about 20 sessions of psychotherapy. The effects of psychotherapy tend to be long lasting. For example, only 25% treated depressed patients relapse, whereas 50% of those who receive antidepressants relapse. Research continues to support those therapies that have been rigorously tested, and differences in effectiveness between therapy types (e.g., cognitive behavioural therapy (CBT), psychodynamic, interpersonal, etc.) tend to be small or negligible for many disorders. Cognitive behavioural therapy is still the most tested therapy modality, though other treatments are also accumulating evidence of efficacy. Treatment is likely facilitated by a therapeutic relationship that is characterized by trust, understanding, acceptance, kindness, and warmth. The effect of the therapist providing the therapy is at least as large as the effect of different therapy techniques. That is, some therapists are unusually effective, whereas others may not help the majority of patients who seek their services. Continuous monitoring of outcomes and providing regular feedback to the therapist improves the therapy’s effectiveness.
Providers and patients can be assured that a broad range of formally defined and tested psychotherapies when provided by skilful therapists are likely to result in appreciable gains in clients including a return to normal functioning. Therapy relationships characterized by trust, understanding, acceptance, and warmth can greatly facilitate change in depression, anxiety, inadequacy, and inner conflicts. When making a decision about which therapy to choose, clients would be wise to consider the therapist as a person at least as much as the type of therapy being offered. Treatment efforts should be based on the best evidence available for treatment types, therapist behaviors, and relationship factors. Routinely monitoring the effects of therapy with each patient will give the therapist ongoing information about their effectiveness and may improve their patients’ outcomes.