Abnormal Psychology, Thirteenth Edition by Ann M. Kring, PowerPoint  Lecture Notes Presentation Chapter 4 Research Methods in Psychopathology Abnormal Psychology, Thirteenth Edition by Ann M. Kring, Sheri L. Johnson, Gerald C. Davison, & John M. Neale © 2015 John Wiley & Sons, Inc. All rights reserved.

Chapter Outline Chapter 4: Research Methods in Psychopathology 9/18/2018 Chapter Outline Chapter 4: Research Methods in Psychopathology I. Science and Scientific Methods II. Approaches to Research on Psychopathology III. Integrating the Findings of Multiple Studies © 2015 John Wiley & Sons, Inc. All rights reserved.

Science and Scientific Methods 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Table 4.1: Approaches to Research on Psychopathology © 2015 John Wiley & Sons, Inc. All rights reserved.

Case Study 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Correlational Method 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Figure 4.1: Correlational vs. Experimental Studies © 2015 John Wiley & Sons, Inc. All rights reserved.

© 2015 John Wiley & Sons, Inc. All rights reserved.

Measuring Correlation 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Figure 4.3: Scatter Diagrams © 2015 John Wiley & Sons, Inc. All rights reserved.

Statistical and Clinical Significance 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? © 2015 John Wiley & Sons, Inc. All rights reserved.

Problems of Causality 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Longitudinal vs. Cross-sectional Designs 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Epidemiological Research 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) © 2015 John Wiley & Sons, Inc. All rights reserved.

Table 4.4: Lifetime Prevalence Rates of Selected Disorders © 2015 John Wiley & Sons, Inc. All rights reserved.

Correlational Research: Behavioral Genetics Methods to determine genetic predisposition (concordance) to psychopathology Family Method Twin Method Adoptees Method © 2015 John Wiley & Sons, Inc. All rights reserved.

Correlational Research: Behavioral Genetics 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 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Correlational Research: Molecular Genetics 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

The Experiment 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Basic Features of Experimental Design 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Figure 4.4: Health Center Visits Before/During Experiment © 2015 John Wiley & Sons, Inc. All rights reserved.

The Experiment External validity Internal validity Control group 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? © 2015 John Wiley & Sons, Inc. All rights reserved.

Experimental Research: Treatment Outcomes 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Figure 4.5: Treatment Outcomes © 2015 John Wiley & Sons, Inc. All rights reserved.

Table 4.5: Examples of Empirically Supported Treatments for Adult Disorders © 2015 John Wiley & Sons, Inc. All rights reserved.

Table 4.7: Percentage of People Seeking Treatment by Country © 2015 John Wiley & Sons, Inc. All rights reserved.

Analogue Experiment Experiments not always possible in psychopathology Ethical or practical constraints Examine related or similar behavior in the lab Induce temporary symptoms Recruit participants with similarities to diagnosable disorders College students who tend to be anxious or depressed Animal research © 2015 John Wiley & Sons, Inc. All rights reserved.

Single-Case Experimental Research 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Integrating Findings from Multiple Studies 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 © 2015 John Wiley & Sons, Inc. All rights reserved.

Table 4.8: Meta-Analysis: One-Year Prevalence Rates for Mental Illness Across 21 European Studies © 2015 John Wiley & Sons, Inc. All rights reserved.

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