March 25, 2015 by Nicholas Spence
In an age of chronic (lifestyle) disease, the quest for effective prevention, management, and treatment interventions is the focus of clinicians and scientists. This includes fostering healthy lifestyle behavioral changes. As discussed elsewhere, motivational interviewing has been credited with having a positive impact on a host of health behavior outcomes, such as body weight, physical activity, fruit and vegetable intake, and medication adherence. Despite the mounting evidence of its effectiveness, surprisingly, our understanding of the causal chain or process by which motivational interviewing results in desirable health behavior outcomes is still a mystery.
A recent paper, “Mechanisms of change within motivational interviewing in relation to health behavior outcomes: A systematic review,” in the journal Patient Education and Counseling, sought to shed some light on this specific issue.
At the outset of the paper, the studies eligible for inclusion in the analysis were quite telling in regards to the lack of work in this area: studies from the last 34 years were examined that delivered individual motivational interviewing, tested a mechanism of change, and focused on a health outcome, excluding addictions. Out of 291 studies, 37 were eligible for inclusion, and only a few of those studies formally examined the process of change empirically between motivational interviewing and health behavior outcomes.
Commonly proposed mechanisms of change were grouped into two categories: therapist behaviors (empathy; motivational interviewing spirit; open questions and reflections; motivational interviewing consistent practices; motivational interviewing inconsistent practices) and client behaviors (change talk and change statements; planning; self-monitoring; motivation; perceived behavior control; self-efficacy; stage of change; self-exploration; and therapeutic alliance).
The results were somewhat surprising. Motivation (i.e., the process that initiates, guides, and maintains goal-oriented behaviors) and motivational interviewing spirit (i.e., collaboration, evoking the client’s ideas about change, and autonomy) were identified as the likely mechanisms mediating the relationship with health behavior outcomes.
There was, however, an added layer of complexity: some evidence showed that the therapist behavior effects were mediated through client behaviors; for example, motivational interviewing spirit increased change talk (i.e., the client revealed consideration, motivation, and commitment to change), which resulted in positive changes in health behavior outcomes.
Another key point worth highlighting was the role of self-efficacy. Self-efficacy has been a construct given much importance in motivational interviewing. Identified as having two dimensions, beliefs and capabilities, self-efficacy is commonly defined as a person’s confidence and capacity or skill set to change lifestyle behaviors. This review, however, found that self-efficacy was unlikely to figure into the process of change, moving from motivational interviewing to health behavior outcomes.
Putting these findings into context, it would be prudent to heed the following point: even though the authors attempted to answer a question of cardinal significance, in the face of the limited body of evidence to evaluate the different pathways, leading from motivational interviewing to health behavioral outcomes, it would be premature to definitively “write off”, or advocate strongly for, a specific mechanism of influence.
In a nutshell, this is an area deserving of much more research attention. Testing theories and related hypotheses to elucidate the causal pathways between motivational interviewing and health behavior outcomes is of primary importance. No doubt, we must move beyond simply demonstrating that motivational interviewing has an impact on desired outcomes. This is not only a scientific concern, as the increasing popularity and promise of motivational interviewing among clinicians, particularly in the context of lifestyle behavior outcomes associated with chronic disease, is without question. We cannot, however, enhance practice, delivery, efficacy, and outcomes in the absence of understanding the process of change.