Comprehensive Notes on Health Psychology Principles, Foundations and Scope of Health Psychology

Introduction to Health Psychology and the Etymology of Health

In the text, health psychology is introduced as a critical field of inquiry, where the desire for the prolongation of life is recognized as one of the most universal of human motives, as stated by Kenneth Arrow ($1963$: $75$). To understand the subject, one must unravel the origin of the word 'health.' Etymologically, 'health' is derived from Old High German and Anglo-Saxon words meaning whole, hale, and holy. The root has been traced back to the Proto-Indo-European term 'kailo-,' which signifies being whole, uninjured, or of good omen. In Old English, this evolved into 'hælan,' meaning to make whole, sound, and well, and 'hal,' which is the root of the adjectives 'whole,' 'hale,' and 'holy,' as well as the greeting 'Hail.' In German, the word became 'heil' (unhurt/unharmed), 'Heil' (good luck/fortune), 'heilig' (holy), and 'heilen' (to heal). Old Norse used 'heill' to denote health, prosperity, and good luck. These roots also provide the basis for everyday English greetings like 'Hello' and 'Hi.'

Historical Perspectives and Ancient Health Frameworks

Ancient links persist between the concepts of health, wholeness, holiness, hygiene, and sanity. Religious texts such as the Bible and the Quran emphasize cleanliness and the removal of evil as pathways to purity. In ancient China and classical Greece, health was conceptualized as a state of harmony, balance, order, or equilibrium with nature. Conversely, disease was traditionally associated with disorder, disintegration, illness, 'crankiness' (the German 'krankheit'), uncleanness, and evil. Galen ($CE\,129-200$), an early Roman physician, expanded upon the Hippocratic tradition, defining 'hygieia' (health) or 'euexia' (soundness) as a balance between the four bodily humours: black bile, yellow bile, phlegm, and blood. Galen posited that the body's 'constitution' or 'state' could be disrupted by excessive heat, cold, dryness, or wetness, often caused by fatigue, insomnia, distress, anxiety, or improper diet. For instance, an excess of black bile was linked to melancholia. This theory was intrinsically tied to the four elements of earth, fire, water, and air ($Table\,1.1$).

Evolution of Health Definitions and the WHO Perspective

The World Health Organization ($WHO$) defined health in $1946$ as 'the state of complete physical, social and spiritual well-being, not simply the absence of illness.' While influential, this definition is often criticized for its idealism, as 'complete' well-being may be unreachable. It also historically overlooked psychological, cultural, and economic factors. Modern health psychology emphasizes 'psychosocial' factors, which describe human behaviour and experience as they influence well-being within a social context. Poverty and social inequalities are strongly associated with health outcomes and must be included in a functional definition. Consequently, a comprehensive definition of health is: 'Health is a state of well-being with satisfaction of physical, cultural, psychosocial, economic and spiritual needs, not simply the absence of illness.'

Need Satisfaction, Well-Being, and Happiness

A key concept in health is need satisfaction. Maslow ($1943$) proposed a hierarchy of needs ($Figure\,1.1$) where health is achieved as a person moves from basic needs—breathing, food, water, sex, sleep, homeostasis, and excretion—toward safety, love/belonging, and self-esteem, eventually reaching self-actualization. Self-actualization represents a 'peak experience' of meaningful existence. However, human needs do not always follow a fixed hierarchy; for example, an extreme sports enthusiast might prioritize self-actualization over safety. Other scholars, such as Doyal and Gough ($1991$), argue that health and autonomy are the most basic universal needs, requiring societal preconditions—political, economic, and ecological—to be fulfilled. Self-Determination Theory ($Ryan\,\text{and}\,Deci,\,2000$) suggests three basic needs: competence, relatedness, and autonomy.

Quality of Life (QoL) and Subjective Well-Being (SWB)

Quality of Life ($QoL$) has been a philosophical interest from Aristotle, who saw happiness as the purpose of life, to Bentham, who viewed it as pleasure without pain. The $WHO$ defines $QoL$ as an individual's perception of their position in life relative to their goals and culture, affected by physical health, psychological state, independence, and environment. Subjective Well-Being ($SWB$), a term championed by Ed Diener (known as 'Dr. Happiness'), refers to the valuations people make regarding their lives, bodies, and minds. Evidence strongly links high $SWB$ to longevity, with some studies suggesting it adds between $4$ and $10$ years to life ($Diener\,\text{and}\,Chan,\,2011$). Luhmann et al. ($2012$) distinguished between 'cognitive' and 'affective' well-being, finding through a meta-analysis of $188$ publications ($65,911$ people) that life events often have more consistent effects on cognitive well-being.

The Theory of Well-Being (TWB) and Attachment

The Theory of Well-Being ($TWB$) explains causal links between physical health, subjective well-being, and life satisfaction. It focuses on developmentally important constructs such as attachment ($Bowlby,\,1969$). The way an infant attaches to a caregiver creates a 'secure base' and a mental model for all future relationships. Attachment style influences many health-related behaviours, including alcohol and drug abuse, smoking, insomnia, and responses to trauma. The theory also identifies a moderate level of consumption and positive affect as significant mediators of health outcomes. Furthermore, the eudaimonic approach focuses on meaning and self-realization, occurring when life activities mesh with authentic values. This is mirrored in Antonovsky's ($1979$) Salutogenic Theory, which emphasizes a 'Sense of Coherence' and purpose as drivers of health.

The Nature and Rationale of Health Psychology

Health psychology is an interdisciplinary field applying psychological knowledge to health, illness, and health care. It is growing rapidly, with psychologists now essential in multidisciplinary teams across cardiology, oncology, paediatrics, and more. One primary rationale for the discipline is that leading causes of mortality are behavioural. For adults aged $15-59$, the leading cause globally in $2002$ was $HIV/AIDS$ ($2,279,000$ deaths), followed by Ischaemic heart disease ($1,332,000$) and Tuberculosis ($1,036,000$). For those aged $60$ and over, Ischaemic heart disease ($5,825,000$ deaths) and Cerebrovascular disease ($4,689,000$) dominated. Because these causes involve behaviour, effective change methods are necessary.

The Global Burden of Disease and DALYs

The Global Burden of Disease ($GBD$) study uses the Disability-Adjusted Life Year ($DALY$) as a quantitative indicator of the burden of disease. One $DALY$ represents the loss of one year of 'healthy' life, calculated as the sum of years of life lost from premature mortality and years lived with disablement. Between $1990$ and $2010$, there was a significant increase in $DALYs$ for certain conditions, most notably a $354\%$ increase for $HIV$. Conversely, progress was seen in reducing $DALYs$ for lower respiratory tract infections and diarrhoea. High blood pressure is the leading risk factor for global disease burden, accounting for $138$ million $DALYs$ ($9.5\%$), followed by tobacco ($6.3\%$) and alcohol ($4.4\%$). Collectively, the top five risk factors account for nearly $30\%$ of the total global burden of disease.

Individualism, Victim Blaming, and the Toxic Environment

Contemporary Western society often promotes 'individualism,' viewing individuals as agents responsible for their own health. This can lead to 'victim blaming,' where illness is seen as a person's 'fault' due to poor lifestyle choices like smoking or lack of exercise. Fitzpatrick ($2001$) compares disease with sin and health with virtue. However, this perspective ignores environmental constraints. The 'obesogenic environment' provides affordable but unhealthy foods on an industrial scale, while the 'socially toxic environment' (Garbarino, $1997$) exposes children to violence and poverty. Brownell ($1994$) argues that the environment is engineered to draw people toward unhealthy habits. Consequently, changing individual behaviour without addressing environmental 'poisoning' is often ineffective.

Measurement Challenges in Health Psychology

Psychology faces a fundamental 'measurement problem.' While natural sciences measure objective physical attributes, psychologists often assign numbers to attributes according to rules—a principle called 'operationism' by S.S. Stevens ($1951$). However, this can be illusory; for example, labeling red=$1$ and blue=$2$ does not make the numbers quantitatively meaningful. Michell ($1999,\,2002$) and Sijtsma ($2012$) argue that psychological attributes like 'Life Satisfaction' may be ordinal rather than quantitative. On Dr. Ed Diener's Satisfaction With Life Scale ($SWLS$), scores range from $5$ (Extremely dissatisfied) to $35$ (Extremely satisfied). Treating these scores as interval data for statistical analysis is an unproven assumption. Despite this, health psychology 'gets by' by focusing on observable outcomes, behaviour changes, and qualitative experiences.

Cultural Perspectives: The African Example

Mainstream health psychology is often ethnocentric, assuming a Western worldview of individualism where illness is caused by atomistic physiological processes. In contrast, many African cultures view individuals as interconnected with relatives, ancestors, and spiritual forces. Markus et al. ($1997$) refer to these cultural assumptions as 'selfways.' In some African settings, the concept of 'enemyship'—the belief that the hatred of another can cause illness—is prevalent. This challenges Western assumptions about social support, as intimate family members might also be perceived as sources of danger or stress. A truly cultural approach to health psychology recognizes that social embeddedness is an inevitable fact of existence.

The Health Onion Framework

The 'Health Onion' is a multi-layered framework for understanding health influences, adapted from Dahlgren and Whitehead ($1991$). It places the individual at the core ($Age,\,sex,\,and\,hereditary\,factors$) and identifies four surrounding layers of influence: (Level $1$) Individual lifestyle factors; (Level $2$) Social and community influences; (Level $3$) Living and working conditions (including education, housing, and health care services); and (Level $4$) General socio-economic, cultural, and environmental conditions. The framework is holistic, interdisciplinary, and acknowledges that health determinants are complex and interconnected, without claiming one level is more important than another.

Filtering Evidence in Evidence-Based Practice (EBP)

Evidence-Based Practice ($EBP$) relies on randomized controlled trials to determine treatment effectiveness. However, the 'filtering' of evidence is highly selective. For example, a systematic review of peer health promotion for young people found $5,124$ citations, but only $12$ ($0.234\%$) were judged to have 'sound' evaluations (Oakley, $2001$). Evidence must typically pass through seven filters: current knowledge/theory, funding priorities, hypotheses, approved methodology, journal publication, systematic reviews, and translation into $EBP$. This process can be wasteful and biased toward established practices, such as preferring pharmacotherapy over psychological therapies or quantitative data over qualitative insights.