Related Experiment Video
Updated: May 21, 2026

Signal Attenuation as a Rat Model of Obsessive Compulsive Disorder
Published on: January 9, 2015
How Much Therapy Is Really Enough? : A Session-by-Session Analysis of the Psychotherapy Dose-Effect Relationship
S W Kadera1, M J Lambert, A A Andrews
1Department of Psychology and Clinical Psychology, Brigham Young University, 284 Taylor Building, P. O. Box 28626, Provo, Utah 84602-8626.
Abstract:
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.
Related Concept Videos
Elements Crucial for Effective Psychotherapy
The Therapeutic Alliance
The therapeutic alliance refers to the relationship between the therapist and the client. The alliance strengthens when the therapist and the client engage in a nurturing, supportive, trusting, empathetic, and respectful relationship, improving therapeutic outcomes. Therapists must monitor this relationship...
Dose Size and Dosing Frequency: Determination Methods
Dose-Response Relationship: Potency and Efficacy
Pharmacokinetic–Pharmacodynamic Relationship: Dose to Pharmacological Effect
Psychotherapy
Pharmacokinetic–Pharmacodynamic Relationship: Intensity of Dose-Effect Relationship
