The Ubiquitous Decay Curve: Service Delivery Similarities in Psychotherapy, Medicine, and Addiction

Accumulating data from three fields of research and practical endeavor point to strong similarities in the way in which service delivery systems operate. Psychotherapy, medical delivery systems, and client behavior in addiction treatment all show the "same" negatively accelerating, declining, decay curve that is based, respectively, on attrition, noncompliance, and relapse across a wide range of independent variables within each research area. Unification and understanding of outcome data and comparisons across treatment modalities can be enhanced by recognition of the apparent universality of the decay function.