Developing adaptive treatment strategies in substance abuse research

For many individuals, substance abuse possesses characteristics of chronic disorders in that individuals experience repeated cycles of cessation and relapse; hence viewing drug dependence as a chronic, relapsing disorder is increasingly accepted. The development of a treatment for a chronic disorder requires consideration of the ordering of treatments, the timing of changes in treatment, and the use of measures of response, burden and adherence collected during treatment to make further treatment decisions. Adaptive treatment strategies provide a vehicle through which these issues can be addressed and thus provide a means toward improving and informing the clinical management of chronic substance abuse disorders. The sequential multiple assignment randomized trial (SMART) is particularly useful in developing adaptive treatment strategies. Simple analyses that can be used with the SMART design are described. Furthermore, the SMART design is compared with standard experimental designs.