Randomized clinical trials support the efficacy of a wide range of psycho-educational interventions. However, the mechanisms through which these interventions improve outcomes are not always clear. At times, the theoretically specified factors within interventions have been shown to have specific effects on patient outcomes. But it has also been argued that other factors not identified in the intervention theory (e.g. "non-specific" factors such as patient expectations and therapeutic patientclinician alliances) have powerful "non-specific" effects that account for most, if not all, of the observed efficacy of psycho-educational interventions. This paper describes important concepts in this debate and discusses key issues in distinguishing between specific and non-specific effects of psycho-educational nursing interventions. Four examples are used to illustrate potential methods of identifying and controlling for non-specific effects in clinical intervention trials.
KeywordsNon-specific effects; placebo effect; intervention methods In a recent editorial, Conn (2008) called for increased efforts to publish reports of studies that quantitatively assess effects of nursing interventions. She emphasized the persistent gap between "real world nursing practice and available empirical evidence about interventions" (p. 913). One critical aspect of such research is identifying an intervention's active components so they can be adequately communicated, transferred, and implemented across populations and settings. In the "real world", nurses do not have time to deliver intervention components that fail to contribute to beneficial outcomes. Moreover, they need to know the specific factors that must be included to reproduce improvements in outcome. It is the role of nurse investigators to determine whether or not the theoretically active components of an intervention result in specific effects on patient outcomes or whether other factors may have influenced outcomes (resulting in non-specific effects). A long history of opinion exists around specific and nonspecific treatment effects in the medical and psychology literatures, but this important topic has received far less attention in nursing. The purpose of this paper is to review key aspects of the historical debate, to discuss the implications of these arguments for tests of psychoeducational interventions in nursing, and to provide examples of approaches that can be used by nurse investigators to account for specific and non-specific treatment effects.
Basic ConceptsIn testing health-related interventions (psycho-educational or otherwise), researchers develop their treatments to include theoretically-derived "specific" factors. That is, they include key elements with theoretically derived actions that are expected to produce the desired change in health outcomes. For example, Johnson's self-regulation theory suggests that providing patients with education including sensory preparation prior to a noxious medical procedure will help them make sense of their experien...