There are a number of distinct specialty areas within health psychology:
• Clinical Health Psychology: This subfield of health psychology is strongly linked to clinical psychology and involves activities such as psychotherapy, behavior modification and health education.
• Community Health Psychology: Individuals working in this subfield of health psychology often focus on developing interventions and prevention techniques at the community-level. These professionals may conduct assessments of communities or work with groups to encourage healthy behaviors or promote behavior change.

Health psychology deals with individual behavior in a social context. However, within the public health sector, behavior is not restricted to behavior of at-risk persons, but also includes behaviors of peers, parents, health professionals, employers, politicians, and others. Unfortunately, while there is a large amount of empirical data available regarding individual behavior of the at-risk person or patient, there is very little data available about behaviors at other social levels.

The first public health applications of psychology were strongly focused on risk perception and risk taking. The best example may be the health belief model, where the perception of the severity of the risk and the susceptibility for the risk were seen as the primary determinants of health-protective behaviors. Over time, it became clear that people have many reasons for health-related behaviors, of which risk perception is often not an important one. In this multicausality approach, there is also a growing recognition of the many psychosocial and environmental influences on individual behavior. Changes in psychosocial determinants (e.g., self-efficacy) are most effective in creating behavior change when paralleled by changes in the social and physical environment(e.g., removal of barriers).