Health Research

What is the placebo effect? An expectation of an effect gives that

effect.

What can increase the placebo effect? 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. 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 potentially:

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: Correlation studies Cross-Sectional studies Longitudinal studies Experimental designs Observational designs

Correlation 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

Observational studies Does not manipulate variables Prospective

Follow disease-free population for years to see what happens

Retrospective Opposite approach Find population with disease and look backward “After the fact” Comparison group is not a control group

• No random assignment• May differ on other factors

Observational studies Retrospective (Cont.)

Two groups• One with subject variable

• (e.g Overweight)• One without subject variable

• (e.g Not overweight)• Measure dependent variable (eg. Smoking)

Looks for risk factors in a disease Factors increasing chance of the disease Demographic Behavioral

The “gold standard” of scientific research 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 (Two or more raters = same results)

Validity Measures what it is designed to measure Criterion validity Predictive validity