Transcript 02-Health Research

Health Research
What is the placebo effect?
• An expectation of an effect gives that
effect.
What can increase the
placebo effect?
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Big pills - not little ones
Colored pills - not white tablets
Capsules - not tablets
Two doses - not one
Injection - not pill
Surgery - not injection
Psychological treatments
subject to the placebo effect.
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Counseling
Hypnosis
Biofeedback
Relaxation training
Massage
Stress & pain management techniques
What can increase the
placebo effect?
• Both patient and physician expectations
How effective is the placebo
effect?
• It can:
– Reduce insomnia
– Decrease low back pain
– Lower high blood pressure
– Decrease burn pain
– Relieve knee pain with sham (false)
surgery
How can we separate the
placebo effect from the real
treatment effect?
• Double-blind design.
Research Methods:
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Correlational studies
Cross-Sectional studies
Longitudinal studies
Experimental designs
Ex Post Facto designs
Correlational studies
• Show the degree of relationship
between two factors
• Cannot indicate cause and effect
Cross-Sectional VS
Longitudinal studies
• Cross-sectional studies
• Compare two or more separate groups
– Faster
– One point in time
• Longitudinal studies
– Compares one group over time
– Longer
– Follow participants over years
Experimental study
• Can determine “cause”
• At least two groups
– Experimental group
– Control group
• Variables
– Independent variable
– Dependent variable
Ex Post Facto designs
• “After the fact”
• Does not manipulate variables
• Two groups
– One with subject variable
• (e.g Overweight)
– One without subject variable
• (e.g Not overweight)
– Measure dependent variable (eg. Smoking)
Ex Post Facto designs
• Comparison group is not a control group
– No random assignment
– May differ on other factors
Research Methods in
Epidemiology
• Epidemiology = study of epidemics ( eg.
AIDS)
• Risk factors
– Demographic
– Behavioral
• Prevalence
– Portion of population with disease
• Incidence
– New cases in a year
Observational studies
• Prospective
– Follow disease-free population for years to
see what happens
• Retrospective
– Opposite approach
– Find population with disease and look
backward
The “gold standard” of
scientific research
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Randomized
Placebo-controlled
Double-blind
Used for:
– Drug studies
– Effectiveness of psychological and
educational interventions
Psychometrics (psychological
tests) in research
• Reliability
– Consistent results
– Test-retest
– Inter-rater
• Validity
– Measures what it is designed to measure
– Criterion validity
– Predictive validity