Health psychology, often referred to as behavioral medicine or medical psychology, is the application of psychological theory to health-related practices. The field of health psychology includes two sub-fields. Behavioral health focuses on prevention of health problems and illnesses, while behavioral medicine focuses on treatment. Health psychology is concerned with the psychology of a range of health-related behaviors, including nutrition, exercise, healthcare utilization, and medical decision-making.

"Healthy eating tips" by the U.S. National Cancer Institute

Nutrition is often researched by health psychologists.

The Biopsychosocial Model

The biopsychosocial model views health and illness behaviors as products of biological characteristics (such as genes), behavioral factors (such as lifestyle, stress, and health beliefs), and social conditions (such as cultural influences, family relationships, and social support). Health psychologists work with healthcare professionals and patients to help people deal with the psychological and emotional aspects of health and illness. This can include developing treatment protocols to increase adherence to medical treatments, weight loss programs, smoking cessation, etc. Their research often focuses on prevention and intervention programs designed to promote healthier lifestyles (e.g., exercise and nutrition programs).

Goals of Health Psychology

There are eight major goals of health psychology:

1. understanding behavioral and contextual factors for health and illness
2. preventing illness
3. investigating the effects of disease
4. providing critical analyses of health policies
5. conducting research on prevention of and intervention in health problems
6. improving doctor-patient communication
7. improving adherence to medical advice
8. finding treatments to manage pain.

Focuses of Health Psychology

Health psychology addresses individual and population-level issues across four domains: clinical, public, community, and critical (social justice).

Clinical Health Psychology

Clinical health psychology refers to the application of scientific knowledge to clinical questions that arise across the spectrum of healthcare. Because it focuses on the prevention and treatment of health problems, clinical health psychology is a specialty practice area for clinical psychologists. Clinical practice includes education on mechanisms of behavior change and psychotherapy.

Public Health Psychology

Public health psychology investigates potential causal links between psychosocial factors and health at the population level. Public health psychologists present research results on epidemiological findings related to health behaviors to educators, policy makers, and health care providers in order to promote public health initiatives for at-risk groups. 

Community Health Psychology

Community health psychology investigates community factors that contribute to the health and well-being. Community health psychology also develops community-level interventions that are designed to combat disease and promote physical and mental health. Examples of community health initiatives might be efforts to eliminate soft drinks from schools, diabetes awareness events, etc.

Critical Health Psychology

Critical health psychology is concerned with the distribution of power and the impact of power differentials on health behaviors, healthcare systems, and health policy. Critical health psychology prioritizes social justice and the universal right to good health for people of all races, genders, ages, and socioeconomic positions. A major concern is health inequality, and the critical health psychologist acts as an agent of change working to create equal access to healthcare.