How Much Therapy Is Really Enough?

A Session-by-Session Analysis of the Psychotherapy Dose-Effect Relationship

¹ Department of Psychology and Clinical Psychology, Brigham Young University, 284 Taylor Building, P. O. Box 28626, Provo, Utah 84602-8626.

Dr. Lambert, Department of Psychology and Clinical Psychology, Brigham Young University, 284 Taylor Building, P. O. Box 28626, Provo, Utah 84602-8626.

Previous investigations of the dose-effect relationship in psychotherapy suggest that therapeutic benefits occur early in treatment.

Approximately 25% of patients have been estimated to improve after 1 session, and 50% improve by 8 sessions. The aim of this study was to compare such estimates with the actual performance of outpatients in therapy. Forty-five patients seen at an outpatient clinic were monitored session by session for evidence of clinically significant change. Results indicated only 22% of patients "recovered" (as defined in this study) after 8 sessions, with the earliest recovery occurring after 2 sessions. Possible reasons for the lower dose-effect relationship found here are discussed.

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