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Health Psychology
Lecture 2
Theory and Research
Lecture 2 - Outline
• Part 1
– Theory and Research
• Part 2
– Placebo Effects
• Part 3
– Assignment #1
Theory
• Example: Heart disease is due to excess levels of cholesterol
• Provide a framework for simplifying and describing data in
a meaningful way
• A set of related assumptions from which, by logical
deductive reasoning, testable hypotheses can be drawn
• Theories are judged in terms of their usefulness
– Clearly stated?
– Bring together known facts?
– Enable us to make predictions?
Theories are useful!
Shelly Taylor (1990). American Psychologist, 45, 40-50.
“As a field, health psychology has made substantial contributions to the
understanding of healthy behaviors and to the comprehension of the myriad
factors that undermine health and often lead to illness.
Much of the strongest work has involved providing theoretical and conceptual
frameworks that elucidate the (non)practice of health behaviors, the role of
stress in affecting illness and illness behavior … these theoretical
conceptualizations constitute major contributions inasmuch as they are often
lacking in traditional medicine and medical practice.
For example, it is difficult for physicians to understand why 93% of patients fail
to adhere to certain aspects of their treatment regimens; social psychological
models not only make sense of these data but suggest ways of ameliorating
them.”
Health Belief Model
• Cognitive-behavioral model (cognitive influence on behav.)
• Readiness to seek preventative health care is shaped by 4
core beliefs…
– Perception of SUSCEPTIBILITY to disease
(perceived personal vulnerability)
– Perceived SEVERITY of disease
– Perceived BENEFITS of action
– Perceived COSTS of action
(Rosenstock, 1966)
Health Belief Model
• Readiness to Take Action = Perceived Threat
• Readiness to Change Behavior = Perceived Benefit of
Taking Action (Threat Reduction)
– Cost-Benefit Analysis
Perceived
Threat
+
Perceived
Benefit
=
Likelihood of
Acting
Health Belief Model - Evaluation
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•
•
•
No place for emotions (fear, denial)
Assumes people make rational choices
Best predictor of actual behavior = barriers to health practices
Overall shows moderate predictive power
– Works moderately well for dental visits, safe sex, etc…
Perceived
Threat
Cues to Action
(internal/external)
+
Perceived
Benefit
=
Likelihood of
Acting
Health Belief Model
Theory of Reasoned Action
• Azjen and Fishbein (1980)
• Cognitive-behavioral model (cognitive influence on behav.)
• Behavioral INTENTION is the best predictor of behavior (!)
Attitudes
+
Subjective Norms
=
INTENTION
BEHAVIOR
Theory of Planned Behavior
• Azjen (1985)
• Cognitive-behavioral model (cognitive influence on behav.)
• Behavioral INTENTION is the best predictor of behavior (!)
Attitudes
Behavioral
Control
+
Subjective Norms
=
INTENTION
BEHAVIOR
Theory of Planned Behavior
Summary - Cognitive Approaches
• Cognitive approaches are good at predicting behavior requiring
conscious decisions (e.g., going to dentist), but not good when
when behavior becomes habitual (e.g., substance abuse).
Learning Theory Approaches
• Focus on situations and rewards, not cognitions
• Health behavior = habits controlled by cues
– not necessarily under conscious control
• Broad-spectrum or multimodal approaches
Situation (SD)
:
BEHAVIOR (B)
Reward (R)
Research in Health Psychology
“the ideal health psychologist is a competent and
highly trained individual equipped to intervene at both
the individual and community levels, and who is able
to conduct high quality research”
(Richards, 1992)
Research
• Body of scientific evidence
• Largely free of self-serving bias
• “evolutionary rather than revolutionary”
– typically takes time and develops gradually
• Research in response to theory (tentative explanation)
Research in Health Psychology
• “Health” involves many variables - hard to research
– Numerous misleading claims (e.g., carcinogenic personality )
• But research does not have to be perfect to be useful!
• Types of research design…
–
–
–
–
–
–
–
Experiment
Ex post facto design (quasi experimental)
Single-subject
Correlational
Retrospective
Prospective (longitudinal)
Epidemiology
Experiment (controlled clinical trial)
• Manipulate independent variable and measure dependent
variable
• Able to determine causality
• Characteristics of a good experiment…
–
–
–
–
–
.
.
.
.
.
Quasi -Experiment (ex post facto)
• Not always able to manipulate the independent variable
– Ethical and practical reasons
• Not able to determine causality
– Groups self-select (no random assignment or manipulation)
– Observe dependent variable
– Able to identify “risk factors”
Correlational Designs
• Observe two (or more) variables
• Data analysis
– Simple correlations (2 variables),
– Path analysis/structural equation modeling (multiple variables)
• Not able to determine causality
– Able to identify “risk factors”
– Correlational studies are often misunderstood
Prospective Studies
• Begin with whole population and observe over time
– Initially healthy
• Cross lagged correlations
• Problems…
– Expensive
– Time consuming
– Attrition rates
Epidemiology
• Scientific discipline that considers the various factors determining the
frequency, distribution, and cause of a disease or disorder
• Risk Factor = any characteristic or condition which occurs with greater
frequency in people with a disease than people without.
• Morbidity = disease
– Incidence = number of new cases in a specified time interval
– Prevalence = total # of cases in a specified time interval
• Mortality = death
– # of deaths to a known cause
– (premature death = death before age 75)
Treatments and Interventions
3 elements of a treatment/intervention:
1)
2)
3)
Assumptions / Goals (Theory!)
Techniques (Theory-driven)
Treatment Evaluation…
a) Outcome - is the person better?
b) Process - why is the person better?
3) Treatment Evaluation…
Experiment (controlled clinical trial)
•
Manipulate independent variable and measure dependent variable
•
Able to determine causality
•
Characteristics of a good experiment…
–
–
–
–
–
•
Random sampling
Random assignment
Valid manipulation of independent variable
Valid and reliable measurement of dependent variable
Control extraneous variables
Placebo effect
Placebo
Active treatment = substance or procedure that is
explicitly directed at the symptoms of the condition in
question.
Placebo = substance or procedure that does not
specifically target the condition being treated
Placebo Effect
Provide about 35% of improvement for a variety of conditions.
– Physical conditions - headaches, warts, etc
– Psychological conditions - pain, depression, etc
Example - Depression
Cognitive-Behaviour…...………….
Antidepressant medication……….
Placebo drug………………………
65-70%
65%
30%
Why the placebo affects…
Expectancies
• Anticipation of the emotional and physiological response
Non-Specific Factors
• Features, or incidental elements, common to all therapeutic interventions
• Eg - doctor-patient relationship, hope, suggestion, expectancies
Demand Characteristics
Classical Conditioning
Can a placebo have a negative effect?
Can a placebo have a negative effect?
Nocebo effect - the flipside of the placebo effect
• case study … “she’s a TC!”
• Inert pills can produce negative side effects
• experiment … reactions to a “poisonous” plant
Placebo effect
• limitations of the placebo effect
• ethical considerations
• implications for research
Implications for Research
Double-blind trials (Sarafino, p. 26)
1.
2.
Diagnosis
Intervention
Independent variable
Experimental group
(active drug)
3.
4.
Placebo group
(inert drug)
Assess on relevant dependent variables
Follow-up (long-term gains)
Control group
(no pills)
Implications for Research
Illness
Results … if the drug is effective!
Experimental group
(active drug)
Placebo group
(inert drug)
Control group
(no pills)
Tutorial Assignment #1
• Practice exercise
– Effect of herbal extracts on health
Empirical Evidence
Hoodia Weight-Loss Pill
– A few years ago South African scientists discovered the plant contained a
previously unknown molecule, which has since been christened P 57.
– You can find pills containing Hoodia extract advertised on the Internet.
– Would you give this pill to patients who want to lose weight?
Educated doctors need to know:
• .
• .
Practice Exercise - Modern Juice
… add a supplement to boost your health!
• Vitamin C (with potent antiviral and antibacterial properties, vitamin
C plays a vital role in strengthening the immune system, especially
with regard to preventing and treating the common cold)
• Echinacea (organic herbal extract, mobilizes the immune system
response to bacterial invaders by increasing the production of white
blood cells)
• Royal Jelly (the sole food of the queen bee, this premium quality
extract is a super-nutrient and well-known booster of immune
function and is rich in protein, vitamins, and enzymes)
• Organic Wheatgrass (nutritional scientists have hailed it as the most
powerful blood, tissue, and colon cleanser. As it detoxifies the liver
and kidneys, it enriches the blood with an array of vitamins and
minerals. 1 or 2 oz a day helps maintain a strong immune system)
Practice Exercise - Modern Juice
… add a supplement to boost your health!
• Hawaiian Spirulina (an organic blue green micro-algae which
contains high doses of 10 readily assimilated essential nutrients.
Beneficial for stress-related mental and physical fatigue and iron
deficiency)
• Panax Chinese Ginseng (considered the most stimulating of all
ginsengs. Helpful to relieve stress and fatigue, and to improve mental
and physical performance, stamina, and exercise)
• Kava Kava (a sacred plant extract from the pepper plant, native to the
South Sea islands. Promotes a deep restful sleep, pain relief with
sedative effects and muscle relaxation)
• Ginko Biloba (an anti-oxidant rich herb that has a scavenging effect
on free-radicals. It increases dopamine, which aids in memory and
mental alertness)
Practice Exercise - Modern Juice
We are interested in whether the consumption of juice
supplements is related to improved health and greater
resistance to illness.
•
Boost immune system
– vitamin C, echinacea, royal jelly, wheatgrass
•
Relieve stress
– Hawiian Spirulina, Ginseng, Kava, Ginko Biloba
1.
Design a correlational study to test this. What can you conclude?
2.
Design a “true” experiment. What can you conclude?
What will you measure, how will you measure it? (reliability and validity)
Design a Correlational Study/True Experiment
–
–
–
Hypothesis/Rationale
Participants
Measures
•
•
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Predictor variable
Outcome variable
Mechanism
–
–
Procedure/Design
Data analysis
–
Conclusions
Term Paper #1
We are interested in whether higher levels of physical activity
are associated with lower cholesterol levels.
1.
Design an ex-post facto (quasi-experimental) study to
test this. What can you conclude?
2.
Design a “true” experiment. What can you conclude?
Maximum Length: 1000 words
Due date: Monday, October 4
References: Sarafino (pp. 25-32, 241-242)