USING MORE THAN ONE THEORY
As there are typically multiple determinants of health and behaviors, an intervention may need to be informed by more than one theory. This is particularly the case for complex health and psychosocial problems in which no single action alone may have a positive effect. Rather, a multicomponent approach informed by one or more theories may be more effective. As multiple pathways may need to be targeted to bring about the expected changes, one theoretical framework may complement another and together explain the different conduits by which the intervention has its impact. Similarly, if the intervention targets a dyad, let’s say a caregiver and the person receiving care, different theories may be needed to articulate the specific pathways by which outcomes are achieved for each party, such as the example of an intervention targeting the behavioral symptoms of persons with dementia. These points are illustrated in the examples described earlier.
Furthermore, multiple theories may be necessary if an intervention is multimodal. A multimodal intervention includes treatment components that intervene through different mechanisms of action. For example, an intervention designed to enhance cognitive abilities by impacting physiological reserve through a physical exercise program and cognitive reserve through a cognitive training program would require multiple theories to understand these distinct potential pathways.
The challenge in using more than one theory is to logically and systematically link them coherently (Michie & Prestwich, 2010). Here is an example of how investigators integrated different frameworks to form a strong rationale for an intervention designed to reduce risk for HIV and sexually transmitted diseases (STDs).
The theoretical framework for the Eban HIV/STD Risk Reduction Intervention integrates components of social cognitive theory (SCT) and an Afrocentric paradigm into a relationship-oriented ecological framework that addresses multilevel risk and protective factors associated with HIV/STD risk reduction among African American HIV- serodiscordant couples. SCT informed the factors in the ecological model that are referred to as ontogenic- or personal-level and micro- or interpersonal-level factors. These SCT tenets are designed to build individual’s and couples’ selfefficacy, behavioral skills, and positive outcome expectancies with respect to HIV/ STDs prevention. SCT behavior change strategies implemented in sessions include guided practice with rewards, modeling of behavioral skills (e.g., condom use) and communication and negotiation skills, and problem solving and decision-making.
The intervention design incorporates an Afrocentric paradigm by organizing session content around discussions of one or more of the 7 principles of Nguzo Saba, which are aimed at addressing community-level or macro- structural-level factors. Through the use of these principles, African American couples learn to link the practice of safer sex to enhancement of cultural and gender pride and to an overall more positive way of living based on a healthy balance between self-protection and peer/community support. (NIMH Multisite HIV/STD Prevention Trial for African American Couples Group, 2008, pp. S16—S17)
Locher et al. (2011) also clearly explain how two theoretical approaches are used complementarily to inform the Behavioral Nutrition Intervention for Community Elders (B-NICE).
The B-NICE study was guided by the theoretical approaches of the Ecological Model (EM) and Social Cognitive Theory (SCT). These theories are especially useful in combination with one another because they emphasize the reciprocal relationship that exists between individual behavior and the social environment; moreover, both have been recommended as particularly well-suited for addressing the problem of poor nutritional health in home-bound older adults. Specifically, we used an EM in designing particular components of the intervention and SCT in developing the manner in which the intervention was implemented. (Locher et al., 2011, p. 3)
Most behavioral interventions will require the use of more than one theoretical framework. To effectively use more than one theory, a clear explication of the link between theories and how each contributes to the intervention design is central.