DPH 801 Module 2 Individual-Level Theories Compared Example

Beliefs, Intentions and Readiness: Comparing Individual-Level Theories for Hypertension Medication Adherence

Student Name

Doctor of Public Health Program, Aspen University

DPH 801: Health Determinants, Disparities, Behavior and Promotion

Instructor Name

Month Day, Year

Beliefs, Intentions and Readiness: Comparing Individual-Level Theories for Hypertension Medication Adherence

Individual-level theories are the most widely used in health promotion, and doctoral practitioners must know their strengths and blind spots. This paper compares three of them, the health belief model, the theory of planned behavior and the transtheoretical model, by applying each to one behavior: taking blood pressure medication as prescribed among Black adults with hypertension in a composite city, where uncontrolled pressure is common.

Why Theory Matters

A review of behavioral science in public health argued that interventions grounded in theory are more likely to be effective than those without, because theory identifies the determinants to target and the mechanisms to test. It also noted that the most frequently used theories focus on individuals, and called for greater use of multilevel and community models (Glanz & Bishop, 2010).

The Behavior

Medication adherence is a proximal behavior on the path to controlled blood pressure. In the composite city, clinic pharmacy records suggest that about four in ten Black patients prescribed antihypertensives have gaps in refills long enough to lose control. Reasons patients give include side effects, cost, feeling well, distrust of medications and difficulty keeping pharmacy hours. Adherence also depends on whether a clinician intensified treatment when pressure stayed high, which is outside the patient's control.

Health Belief Model

The health belief model locates action in a person's appraisal of threat and of the recommended response: how vulnerable they feel, how serious the condition seems, what they expect to gain and what stands in the way, with cues and confidence added in later versions. A classic review found perceived barriers to be the strongest single predictor across behaviors (Janz & Becker, 1984). For adherence, the model points to beliefs that hypertension is serious only when symptoms appear and to barriers such as cost and side effects.

Theory of Planned Behavior

The theory of planned behavior places intention at the center and traces it to attitudes toward the behavior, perceived social expectations and perceived control (Ajzen, 1991). Applied to adherence, it highlights family and church members' views of medication, the patient's sense of control over refills and routines, and overall attitudes toward taking pills daily.

Transtheoretical Model

The transtheoretical model describes change as movement through stages of readiness and emphasizes processes, decisional balance and self-efficacy at each stage (Prochaska & Velicer, 1997). Adherence is an ongoing behavior rather than a single change, so the model is most useful for patients newly diagnosed or restarting treatment, who may be ambivalent.

Constructs Compared

The table compares how each theory frames adherence.

What the Theories Miss

All three focus on the individual's mind. None directly addresses pharmacy deserts, costs set by insurers, clinic hours that conflict with hourly jobs or distrust rooted in experiences of discrimination in health care. The determinants analyzed in the previous module show that these structural factors shape adherence as much as beliefs do.

Critiques From an Equity Perspective

Relying on individual models can frame poor adherence as a personal failing and lead to programs, such as reminder texts, that help people already able to adhere. An equity perspective asks which barriers are structural and which can be addressed by changing systems, such as ninety-day refills, pharmacy delivery or free medications.

Combining Theories

A doctoral practitioner can combine individual theories with multilevel frameworks. Constructs such as perceived barriers and control can be measured and addressed through system changes, while norms can be engaged through community settings. The ecological perspective, discussed in later modules, provides the structure for combining them.

Measurement

Each theory offers measurable constructs: validated scales exist for beliefs about medicines, intention and perceived control, and stage of change. Measuring constructs at baseline allows an intervention to target the most influential ones for the local population and to test whether they changed.

Evidence on Each Theory

Each theory has supporting evidence and critics. The health belief model's constructs predict preventive behaviors moderately, with barriers most consistent. The theory of planned behavior explains a substantial share of intentions but less of behavior. The transtheoretical model is widely used, but trials of stage-matched interventions have produced mixed results.

Applying Theories With Communities

Doctoral practitioners should test theories against community experience. Focus groups with Black men with hypertension could reveal which beliefs and norms matter most, whether readiness varies and which barriers are structural. Theory then guides questions rather than dictating answers.

Selecting Among Theories

Selection depends on the behavior and setting. For a clinic-based adherence program, the health belief model's barriers and benefits may be most useful; for a church-based program, planned behavior's norms matter more; for newly diagnosed patients, readiness may guide counseling. A single program may use constructs from more than one.

Implications for the Course Project

The comparison suggests that individual constructs, especially perceived barriers, perceived control and self-efficacy, should be measured and addressed, but within a framework that also acts on community and policy levels. Later modules develop that framework.

Doctoral-Level Critique

A doctoral analysis goes beyond describing theories to asking whose experience they were built on. Many individual models were developed and tested mainly with white, middle-class samples, which may limit their explanatory power for groups facing discrimination. Testing constructs in the target population, rather than assuming they transfer, is essential.

Summary Judgment

In sum, each theory contributes a useful lens, but none is sufficient for a disparity rooted in structure. The next modules therefore turn to interpersonal and community models.

Conclusion

The health belief model highlights silent-disease beliefs and barriers, the theory of planned behavior highlights norms and control and the transtheoretical model highlights readiness. Each explains part of medication adherence among Black adults with hypertension, and each misses structural barriers. Used within a multilevel design, their constructs can sharpen an intervention; used alone, they risk addressing symptoms rather than causes.

References

Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50(2), 179-211. https://doi.org/10.1016/0749-5978(91)90020-T

Glanz, K., & Bishop, D. B. (2010). The role of behavioral science theory in development and implementation of public health interventions. Annual Review of Public Health, 31, 399-418. https://doi.org/10.1146/annurev.publhealth.012809.103604

Janz, N. K., & Becker, M. H. (1984). The health belief model: A decade later. Health Education Quarterly, 11(1), 1-47. https://doi.org/10.1177/109019818401100101

Prochaska, J. O., & Velicer, W. F. (1997). The transtheoretical model of health behavior change. American Journal of Health Promotion, 12(1), 38-48. https://doi.org/10.4278/0890-1171-12.1.38