1. The Health Belief Model (HBM) is a psychological model that attempts to explain and predict health behaviours by focusing on the attitudes and beliefs of individuals. The HBM was developed in the 1950s as part of an effort by social psychologists in the United States Public Health Service to explain the lack of public participation in health screening and prevention programmes (e.g., a free and conveniently located tuberculosis screening project). Since then, the HBM has been adapted to explore a variety of long- and short-term health behaviours, including sexual risk behaviours and the transmission of HIV/AIDS. The key variables of the HBM are as follows (Rosenstock, Strecher and Becker, 1994):

• Perceived Threat: Consists of two parts: perceived susceptibility and perceived severity of a health condition.
  
  • Perceived Susceptibility: One's subjective perception of the risk of contracting a health condition,
  • Perceived Severity: Feelings concerning the seriousness of contracting an illness or of leaving it untreated (including evaluations of both medical and clinical consequences and possible social consequences).

• Perceived Benefits: The believed effectiveness of strategies designed to reduce the threat of illness.
• Perceived Barriers: The potential negative consequences that may result from taking particular health actions, including physical, psychological, and financial demands.
• Cues to Action: Events, either bodily (e.g., physical symptoms of a health condition) or environmental (e.g., media publicity) that motivate people to take action. Cues to actions is an aspect of the HBM that has not been systematically studied.
• Other Variables: Diverse demographic, sociopsychological, and structural variables that affect an individual's perceptions and thus indirectly influence health-related behaviour.
• Self-Efficacy: The belief in being able to successfully execute the behaviour required to produce the desired outcomes. (This concept was introduced by Bandura in 1977.)

"The Health Belief Model (HBM) was one of the first models that adapted theory from the behavioral sciences to health problems, and it remains one of the most widely recognized conceptual frameworks of health behavior. It was originally introduced in the 1950s by psychologists working in the U.S. Public Health Service (Hochbaum, Rosenstock, Leventhal, and Kegeles). Their focus was on increasing the use of then-available preventive services, such as chest x-rays for tuberculosis screening and immunizations such as flu vaccines. They assumed that people feared diseases, and that health actions were motivated in relation to the degree of fear (perceived threat) and expected fear-reduction potential of actions, as long as that potential outweighed practical and psychological obstacles to taking action (net benefits)."