The study of psychological and behavioural processes in health, illness, and healthcare is known as health psychology. It seeks to comprehend how psychological, behavioural, and cultural factors influence physical health and illness. Psychological factors can have a direct impact on health. Chronically occurring environmental stressors, for example, that affect the hypothalamic–pituitary–adrenal axis can be harmful to health in the long run. Behavioral factors can also have an impact on a person's health. Certain behaviours, for example, can either harm (smoking or consuming excessive amounts of alcohol) or benefit (health) over time (engaging in exercise). A biopsychosocial approach is used by health psychologists. In other words, health psychologists consider health to be the result of psychological (e.g., thoughts and beliefs), behavioural (e.g., habits), and social processes as well as biological processes (e.g., a virus, tumour, etc). (e.g., socioeconomic status and ethnicity)
Health psychologists can improve health by working directly with individual patients or indirectly in large-scale public health programmes by understanding psychological factors that influence health and constructively applying that knowledge. Furthermore, health psychologists can assist in training other healthcare professionals (such as physicians and nurses) to use the knowledge generated by the discipline when treating patients. Health psychologists work in a variety of settings, including hospitals and clinics alongside other medical professionals, public health departments working on large-scale behaviour change and health promotion programmes, and universities and medical schools where they teach and conduct research.
Although its roots can be traced back to clinical psychology,  four distinct divisions within health psychology and one related field, occupational health psychology (OHP), have emerged over time. Clinical health psychology, public health psychology, community health psychology, and critical health psychology are the four divisions. Division 38 of the American Psychological Association (APA), the Division of Health Psychology of the British Psychological Society (BPS), the European Health Psychology Society, and the College of Health Psychologists of the Australian Psychological Society are professional organisations for the field of health psychology (APS). The American Board of Professional Psychology offers advanced certification as a clinical health psychologist in the United States.
Origins and development
Health psychology evolved in various forms in various societies. Psychological factors in health had been studied by disciplines such as psychosomatic medicine and later behavioural medicine since the early twentieth century, but these were primarily branches of medicine, not psychology.
The United States William Schofield wrote a report for the APA titled The Role of Psychology in the Delivery of Health Services in 1969.
While there were exceptions, he discovered that at the time, psychological research frequently separated mental and physical health and paid little attention to psychology's impact on physical health. Schofield, one of the few psychologists working in this field at the time, proposed new methods of education and training for future psychologists. In response to his proposal, the APA formed a task force in 1973 to investigate how psychologists could|
(a) assist people in managing their health-related behaviours,
(b) assist patients in managing their physical health problems, and
(c) train healthcare staff to work more effectively with patients.
In the 1970s, health psychology emerged as a distinct discipline of psychology in the United States. In medicine, there was a growing understanding of the effect of behaviour on health in the mid-twentieth century. The Alameda County Study, which began in the 1960s, found that people who ate regular meals (e.g., breakfast), maintained a healthy weight, slept enough, did not smoke, drank little alcohol, and exercised regularly were in better health and lived longer. Furthermore, psychologists and other scientists were discovering links between psychological and physiological processes.
In 1977, the American Psychological Association (APA) added a division devoted to health psychology, led by Joseph Matarazzo. Matarazzo delivered a speech at the first divisional conference that helped define health psychology. "Health psychology is the aggregate of the specific educational, scientific, and professional contributions of the discipline of psychology to the promotion and maintenance of health, the prevention and treatment of illness, the identification of diagnostic and etiologic correlates of health, illness, and related dysfunction, as well as the analysis and improvement of the healthcare system and health policy formation," he defined the new field. Similar organisations sprang up around the world in the 1980s. The British Psychological Society established a Division of Health Psychology in 1986. In 1986, the European Health Psychology Society was founded as well. Other countries, including Australia and Japan, have established similar organisations. Universities began to establish doctoral training programmes in health psychology. Post-doctoral level health psychology training programmes were established in the United States for individuals who had completed a doctoral degree in clinical psychology.
For many years, psychologists in the United Kingdom have worked in medical settings (in the UK sometimes the field was termed medical psychology). Medical psychology, on the other hand, was a relatively small field aimed primarily at assisting patients in adjusting to illness. The reconsideration of the Medical Section's role by the BPS resulted in the emergence of health psychology as a distinct field.] In a letter to the BPS Bulletin, Marie Johnston and John Weinman argued that a Health Psychology Section was desperately needed. The section was established at the BPS London Conference in December 1986, with Marie Johnston as chair. A review of "Current Trends in Health Psychology" was organised at the Annual BPS Conference in 1993, and a definition of health psychology as "the study of psychological and behavioural processes in health, illness, and healthcare" was proposed.
In 1993, the Health Psychology Section was designated as a Special Group, and in 1997, it was elevated to divisional status within the UK. With the awarding of divisional status, health psychologists' individual training needs and professional practise were recognised, and members were able to obtain chartered status with the BPS. The BPS continued to regulate training and practise in health psychology until 2010, when statutory registration with the Health Professions Council took over the regulation of professional standards and qualifications.
A number of relevant trends coincided with the emergence of health psychology, including:
Epidemiological evidence linking behavior and health.
The addition of behavioral science to medical school curricula, with courses often taught by psychologists.
The training of health professionals in communication skills, with the aim of improving patient satisfaction and adherence to medical treatment.
Increasing numbers of interventions based on psychological theory (e.g., behavior modification).
An increased understanding of the interaction between psychological and physiological factors leading to the emergence of psychophysiology and psychoneuroimmunology (PNI). [
The health domain having become a target of research by social psychologists interested in testing theoretical models linking beliefs, attitudes, and behavior.
The emergence of AIDS/HIV, and the increase in funding for behavioral research the epidemic provoked.
The formation of academic/professional bodies to promote research and practise in health psychology was followed by the publication of a series of textbooks that laid out the discipline's interests.
Understanding behavioral and contextual factors
Health psychologists conduct research to identify behaviours and experiences that promote health, cause illness, and affect the efficacy of health care. They also make policy recommendations to improve health care. To promote health and prevent illness, health psychologists have worked to develop methods to reduce smoking and improve daily nutrition. They have also investigated the link between illness and individual characteristics. For example, health psychology has discovered a link between thrill seeking, impulsiveness, hostility/anger, emotional instability, and depression on the one hand, and high-risk driving on the other.
Health psychology is also concerned with contextual factors that influence health, such as economic, cultural, community, social, and lifestyle factors. Smoking cessation is hampered by physical addiction. Some research suggests that seductive advertising contributes to psychological dependence on tobacco, while other studies have found no link between media exposure and smoking in youth. According to OHP research, people who work in jobs with little decision latitude and a high psychological workload are more likely to develop cardiovascular disease. Other research has found a link between unemployment and high blood pressure. Epidemiologic studies show a link between social class and cardiovascular disease.
Health psychologists also aim to change health behaviours in order to help people stay healthy while also assisting patients in adhering to disease treatment regimens (also see health action process approach). For this purpose, health psychologists use cognitive behavioural therapy and applied behaviour analysis (also known as behaviour modification).
Health psychologists, as previously stated, promote health through behavioural change; however, they also attempt to prevent illness in other ways. Health psychologists work to help people live healthier lives by developing and implementing programmes that encourage people to make lifestyle changes such as quitting smoking, drinking less alcohol, eating more healthily, and exercising regularly. Tobacco use has been targeted in campaigns informed by health psychology. Tobacco products are most commonly consumed by those who can least afford them. Tobacco gives people a way to control aversive emotional states that come with the daily stressors that characterise the lives of the poor and vulnerable. Because many people do not recognise or minimise the risk of illness in their lives, practitioners emphasise education and effective communication as part of illness prevention. Furthermore, many people are unable to put their knowledge of health practises into practise due to daily pressures and stresses. Anti-smoking campaigns are a common example of population-based attempts to motivate the smoking public to reduce their reliance on cigarettes.
Health psychologists also aim at educating health professionals, including physicians and nurses, in communicating effectively with patients in ways that overcome barriers to understanding, remembering, and implementing effective strategies for reducing exposures to risk factors and making health-enhancing behavior changes.
Health psychologists also aim to educate health professionals, such as physicians and nurses, on how to communicate effectively with patients in ways that overcome barriers to understanding, remembering, and implementing effective strategies for reducing risk factors and changing health-promoting behaviours.
OHP also provides evidence that stress-reduction interventions in the workplace can be effective. Kompier and his colleagues, for example, demonstrated that a variety of interventions aimed at reducing stress in bus drivers benefited both employees and bus companies.
The effects of disease
Health psychologists study how disease affects people's psychological well-being. A person who becomes seriously ill or injured is subjected to a plethora of practical stressors. These stressors include difficulties in meeting medical and other bills, difficulties in obtaining proper care when returning home from the hospital, difficulties in caring for dependents, the experience of having one's sense of self-reliance compromised, gaining a new, unwanted identity as a sick person, and so on. These stressors can lead to depression, low self-esteem, and other negative outcomes.
Health psychology is also concerned with improving the lives of people who are nearing the end of their lives. When there is little hope of recovery, health psychologist therapists can improve the patient's quality of life by assisting the patient in regaining some of his or her psychological well-being. Health psychologists are also concerned with providing bereaved people with therapeutic services.
Critical analysis of health policy
Critical health psychologists investigate how health policy affects inequities, inequalities, and social injustice. These research avenues broaden the scope of health psychology beyond the level of individual health to include an examination of the social and economic determinants of health within and between regions and nations. Critical health psychologists have used qualitative methods that focus on the health experience to critique and deconstruct the individualism of mainstream health psychology.
Health psychologists, like psychologists in the other major psychology disciplines, have advanced knowledge of research methods. Health psychologists use this knowledge to conduct research on a wide range of topics. Health psychologists, for example, conduct research to answer questions such as:
What influences healthy eating?
How is stress linked to heart disease?
What are the emotional effects of genetic testing?
How can we change people's health behavior to improve their health?
Teaching and communication
Health psychologists may also be in charge of training other health professionals on how to deliver interventions to promote healthy eating, smoking cessation, weight loss, and so on. Health psychologists also teach other health professionals communication skills such as how to break bad news or support behaviour change in order to improve treatment adherence.
Improving doctor–patient communication
During medical consultations, health psychologists facilitate communication between physicians and patients. There are numerous issues with this process, with patients demonstrating a significant lack of understanding of many medical terms, particularly anatomical terms (e.g., intestines).  One area of investigation on this subject is "doctor-centered" or "patient-centered" consultations. In general, doctor-centered consultations are directive, with the patient answering questions and playing a smaller role in decision-making. Although this style is preferred by the elderly and others, many people dislike the sense of hierarchy or ignorance it fosters.
Improving adherence to medical advice
Health psychologists conduct research and practise to encourage people to follow medical advice and stick to treatment regimens. Patients frequently forget to take their pills or choose not to take their prescribed medications due to side effects. Failure to take prescribed medication is expensive and wastes millions of usable medicines that could otherwise be used to help others. Adherence rates are difficult to estimate (see below); however, there is evidence that adherence could be improved by tailoring treatment programmes to individuals' daily lives. Furthermore, traditional cognitive-behavioral therapies have been adapted for people with chronic illnesses and comorbid psychological distress to include modules that encourage, support, and reinforce adherence to medical advice as part of the overall treatment approach.
Ways of measuring adherence
Health psychologists have identified a number of ways of measuring patients' adherence to medical
Counting the number of pills in the medicine bottle
Using "Trackcap" bottles, which track the number of times the bottle is opener
Pain anomalies such as episodic analgesia, causalgia, neuralgia, and phantom limb pain are studied in health psychology in order to find treatments to reduce or eliminate pain. Although measuring and describing pain has been difficult, the development of the McGill Pain Questionnaire has aided in making progress in this area. Pain treatments include patient-administered analgesia, acupuncture (which has been shown to be effective in reducing pain in osteoarthritis of the knee), biofeedback, and cognitive behaviour therapy.
Health psychologist roles
The positions held by health psychologists in applied settings such as the UK's NHS and private practise are listed below.
Consultant health psychologist: A consultant health psychologist will be in charge of health psychology in public health, including tobacco control and smoking cessation services, as well as professional leadership in the management of health trainers.
Principal health psychologist: A principal health psychologist, for example, could direct the health psychology service at one of the UK's top heart and lung hospitals, providing clinical care to patients and advising all members of the multidisciplinary team.
Health psychologist: A health psychologist's role could include providing health psychology input to a weight management centre, for example. Psychological evaluation of treatment, development and delivery of a customised weight management programme, and advice on methods to improve adherence to health advice and medical treatment.
Research psychologist: Research health psychologists conduct health psychology research, such as investigating the psychological impact of receiving a dementia diagnosis or evaluating methods of providing psychological support to people with burn injuries. Research in the field of health promotion can also be conducted, for example, to investigate the determinants of healthy eating or physical activity, or to better understand why people misuse substances.
Health psychologist in training/assistant health psychologist: A health psychologist will gain experience as an assistant/in training assessing patients, delivering psychological interventions to change health behaviours, and conducting research while being supervised by a qualified health psychologist.
Health psychologists in the United Kingdom are registered with the Health Professions Council (HPC) and have completed sufficient training to be eligible for full membership in the British Psychological Society's Division of Health Psychology. Registered health psychologists who are chartered with the BPS will have completed a minimum of six years of training and a minimum of three years of specialisation in health psychology. Health psychologists in training must have completed BPS Stage 1 training and be registered with either the BPS Stage 2 training route or a BPS-accredited university doctoral health psychology programme. Health psychologists who have completed their training can work in a variety of settings, including the NHS, universities, schools, private healthcare, and research and charitable organisations. A health psychologist in training may work in clinical settings while pursuing registration and chartered status.  A health psychologist will have demonstrated expertise in the following areas:
professional skills (including implementing ethical and legal standards, communication, and teamwork),
research skills (including designing, conducting, and analyzing psychological research in numerous areas),
consultancy skills (including planning and evaluation),
teaching and training skills (including knowledge of designing, delivering, and evaluating large and small scale training program),
intervention skills (including delivery and evaluation of behavior change interventions)
Throughout their careers, all qualified health psychologists must participate in and document their continuing professional development (CPD) for psychology.
The Psychology Board of Australia registers health psychologists in Australia. A minimum of six years of training and a two-year registrar programme are required to become an endorsed health psychologist. Each year, health psychologists must also complete continuing professional development (CPD).
Health psychologists are registered with the New Zealand Psychologists Board in New Zealand and work within the psychologist scope of practise. A Masters in Health Psychology and a two-year registration Postgraduate Diploma in Health Psychology at the University of Auckland are required for the training pathway to become a registered health psychologist. Graduates may pursue careers in research and health promotion in universities and private settings in addition to clinical work in primary, secondary, and tertiary healthcare settings. Health psychologists can become members of the Institute of Health Psychology (IHP) as practitioners, academics, or students.