Chapter 4 -- Research Methods in Psychopathology

I. Research Goals of Abnormal Psychology

A. Describe with systematic observations (measure variables and collect data)
B. Explain by identifying causes and effects (use theory and experiments)
C. Predict future occurrences (hypotheses and correlations)
D. Control through therapy, medication, education, and support
(outcome research)

II. Types of Participant Samples

A. Convenience (whoever is available and willing, most common sample) (less generalizable)
B. Selected or screened (chosen because of specific characteristics such as need for treatment) (less generalizable)
C. Stratified (chosen to represent demographic characteristics of the population such as gender, age, and race, often used in national surveys) (more generalizable)
D. Random (everyone in population has an equal chance of being chosen, seldom used because of high refusal to participate) (more generalizable)

III. Types of Research Validity

A. Internal Validity is the extent to which the results of the study can be attributed to the independent variable (experiments have the highest internal validity)
B. External Validity is the extent to which the results of the study can be generalized to others outside the study (representative or random samples have the highest external validity)
C. Confound is any factor that makes the results uninterpretable and threatens validity

IV. Approaches to Research on Psychopathology
A. Case Study - collection of biographical information
1. Excellent source of hypotheses
2. Cannot provide causal evidence because of alternative hypotheses
3. May be biased by observer's theoretical viewpoint
B. Correlation - study of 2 or more variables measured as they exist in nature
1. Often used to study risk and protective factors for disorders
2. Cannot determine cause and effect
C. Experimental Method
1. Most powerful to study cause and effect
2. Some variables may not be ethical to manipulate

V. Experimental Methods
A. Independent Variable (possible cause) is the phenomenon that is manipulated (cognitive therapy) to bring about change in a dependent variable
B. Dependent Variable (outcome measured) is the phenomenon that is measured (depression) and expected to be influenced by the independent variable
C. Experimental Group receives treatment or experimental manipulation (cognitive therapy)
D. Control Group will not receive treatment
E. Placebo Control Group is given procedures with the expectations of change (goal-setting workshop), but do not receive the treatment or manipulation being tested
F. Randomization is assignment to conditions so that everyone in sample has an equal of being in the experimental or control groups
G. Manipulation check makes sure that the experimental group is getting the treatment

VI. Empirically Supported Treatment for Adult Disorders

A. Depression
1. Cognitive therapy
2. Behavior therapy
3. Interpersonal therapy
4. Problem solving therapy
5. Self-control therapy
B. Generalized Anxiety Disorder
1. Cognitive therapy
2. Applied relaxation
C. Social Anxiety
1. Exposure
2. Cognitive Behavioral group therapy
3. Systematic desensitization

VII. Correlational Methods assesses the degree to which two variables are associated (ranges between +1 and -1)
A. Positive correlation occurs when one variable increases as another variable increases
B. Negative correlation occurs when one variable decreases as another variable increases
C.Epidemiological research uses the correlational method to examine the relationship of risk (negative) and protective (positive) factors to the prevalence (number of people with a disorder at any time) incidence (number of new cases in a specified time), and duration of disorders

VIII. Lifetime Prevalence Rates of Disorders by Gender
A. Major Depressive Disorder (20.2% Female; 13.2% Male)
B. Alcohol Abuse (19.6% Male; 7.5% Female)
C. Social Anxiety (13.0% Female; 11.1% Male)

IX. Single-Case Experimental Design assesses someone first and then manipulates a variable to create change
A. Multiple baseline design examines one person over time with A-B-A-B experiment in which A is baseline and B is treatment
B. Strength of this approach is to economically test a treatment and get multiple observations (good internal validity)
C. Weakness is the limited generalizabilty (poor external validity)

X. Genetic research examines genotypes (unique genetic makeup) and phenotypes (observable characteristics or behavior)
A. Twin studies compare twins with unrelated or less closely related individuals to examine genetic influences
B. Adoption studies compare first-degree relatives reared in different families to examine environmental influences