Abnormal Psychology, Twelfth Edition
by
Ann M. Kring,
Sheri L. Johnson,
Gerald C. Davison,
& John M. Neale
Copyright © 2012 John Wiley & Sons, Inc. All rights reserved.
 Chapter
4: Research Methods in the Study of
Psychopathology
I. Science and Scientific Methods
II. Approaches to Research on Psychopathology
III. Integrating the Findings of Multiple Studies
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Science
= “to know”
• The systematic pursuit of knowledge through
observation
• Scientists gather data to test theories
 Theory
• Set of propositions developed to explain what
is observed
 A good theory is falsifiable
 Allows for disconfirmation
 Hypotheses
• Specific predictions about what will occur if a
theory is correct
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.

Detailed biographical
description of an
individual
• Family history
• Medical status
• Educational and work
background
• Information about peer and
romantic relationships
• Personality and adjustment
issues
• Current difficulties and prior
experiences in therapy

Usefulness
• Rich description, especially
helpful for rare disorders
• Disprove hypothesis
• Generate hypotheses

Limitations
• Paradigm may influence
observations
• Cannot rule out alternative
explanations
• Cannot prove hypothesis
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Do
variable X and variable Y vary together?
• Are they related in a systematic way?
 Do people who experience more stress have more
headaches?
 Variables
measured but not manipulated
 Cannot determine cause or effect
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.

Correlation Coefficient (r.)
• Varies from -1.0 to +1.0
 e.g., -1.0, -0.65, -0.33, 0, +0.22, +0.70, +1.00

Strength
• The higher the absolute value, the stronger the relationship
 (-0.9 > +0.6; +0.9 > -.08)

Direction
• Positive
 Higher scores on Variable X associated with higher scores on Variable Y
• Negative
 Higher scores on Variable X associated with lower scores on Variable Y
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Statistical
significance
• Probability ≤ .05
• Can be influenced by number of participants
 Larger samples increase likelihood of significance
 Clinical
significance
• Is the association meaningful as well as statistically
significant?
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Correlation
does not imply causality
 Directionality problem
• Variable X may cause Variable Y
• Variable Y may cause Variable X
 Third-variable
problem
• Variable Z causes both Variable X and Variable Y
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Longitudinal
• Studies participants over time
• Examines whether causes are present before disorder
develops
• High-Risk Method
 Include only those who are at greatest likelihood of developing a
disorder
 Reduces the cost of longitudinal research
 Cross-sectional
• Causes and effects measured at the same time
 Confounds
• Third variable may produce changes in two correlated variables
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Epidemiology
• Study of the distribution of disorders in a population and
possible correlates
 Three features of a disorder
• Prevalence
• Incidence
• Risk Factors
 The National Comorbidity Survey–Replication
• Large-scale national survey
• Used structured interviews to collect information on the
prevalence of several diagnoses (Kessler et al., 2005).
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Methods
to determine genetic
predisposition (concordance) to
psychopathology
• Family Method
• Twin Method
• Adoptees Method
© 2012 John Wiley & Sons, Inc. All rights reserved.

Family studies
• First-degree relatives (parents, children, siblings)
 50% shared genes
• Second-degree relatives (aunts, uncles, grandparents)
 25% shared genes
• Index cases/Probands
 Sample of individuals with psychopathology

Twin studies
• Monozygotic (MZ) or identical twins
 100% shared genes
• Dizygotic (DZ) or fraternal twins
 50% shared genes
• Concordance
 Co-occurrence or similarity of diagnosis

Adoption studies
• Study of adoptees who have biological parents with psychopathology

Cross-fostering
• Study of adoptees who have adoptive parents with psychopathology
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Association
studies
• Examine the relationship between a specific allele
and a trait or behavior in the population
 Genome-wide
association studies (GWAS)
• Examines the entire genome of a large group of
people to identify variations between people
© 2012 John Wiley & Sons, Inc. All rights reserved.


Provides information about causal relationships
Involves:
• Random assignment
• Independent variable (manipulated variable)
• Dependent variable (measured variable)


Can evaluate treatment effectiveness
Experimental Effect
• Differences between groups
© 2012 John Wiley & Sons, Inc. All rights reserved.
 The
investigator manipulates an independent
variable.
 Participants are assigned to the conditions by
random assignment.
 Researcher measures a dependent variable
that is expected to vary with conditions of the
independent variable.
 Experimental effect
• Differences between conditions on the dependent
variable
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Internal
validity
• Extent to which experimental effect is due to independent
variable
 Control
Group
• Participants who do not receive treatment
• Standard against which treatment effectiveness is judged
 External
validity
• Extent to which results generalize beyond the study
 Would results apply to others besides the study participants?
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Research
designed to answer the question:
“Does treatment work?”
 Empirically supported treatments
• Treatment Manuals
• Control Groups
 Placebo
 Double-blind procedure
• Sample Composition
 Exclusion of diverse populations
• Efficacy and Effectiveness
• Need for dissemination
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
 Experiments
not always possible in
psychopathology
• Ethical or practical constraints
 Examine
lab
related or similar behavior in the
• Induce temporary symptoms
• Recruit participants with similarities to
diagnosable disorders
 College students who tend to be anxious or depressed
• Animal research
© 2012 John Wiley & Sons, Inc. All rights reserved.


Examine how individual
participants respond to
changes in the
independent variable.
Reversal (ABAB) Design
• The reversal technique
not always possible
 Initial state may not be
recoverable
© 2012 John Wiley & Sons, Inc. All rights reserved.

Meta-analysis
• Identify relevant studies
• Compute effect size
 Transforms results to a
common scale

Smith et al. (1980)
• Meta-analyzed 475 outcome
studies
 Involved 25,000 subjects
• Results: Psychotherapy is
effective
© 2012 John Wiley & Sons, Inc. All rights reserved.
© 2012 John Wiley & Sons, Inc. All rights reserved.
Copyright 2012 by John Wiley & Sons, Inc. All
rights reserved. No part of the material protected
by this copyright may be reproduced or utilized in
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© 2012 John Wiley & Sons, Inc. All rights reserved.