1. © Cengage Learning 2016 Research Methods for Studying Mental Disorders 4

2. © Cengage Learning 2016 Scientific method –Systematic data collection, controlled observation, and testing hypotheses Hypothesis –Tentative explanation for certain facts or observations Theory –Group of principles and hypotheses that together explain some aspect of a particular area of inquiry Research Methods Used to Study Mental Disorders

3. © Cengage Learning 2016 Replication –Repeating results under similar test conditions Replicating research has resulted in changes to previous “conclusive” results –Examples: Childhood vaccines may cause autism Antidepressants raise suicide risk in children and adolescents Most sexually abused children exhibit signs of trauma Importance of Replication

4. © Cengage Learning 2016 Development of hypotheses about relationships Potential for self-correction Consideration for reliability and validity Use of operational definitions Acknowledgement of base rates Evaluation based on statistical significance Characteristics of Clinical Research

5. © Cengage Learning 2016 Best tool for testing cause-and-effect relationships Components of a simple experiment –Experimental hypothesis –Independent variable Manipulated by the experimenter –Dependent variable Expected to change as a result of manipulating the independent variable Experiments

6. © Cengage Learning 2016 Experimental group –Group exposed to an independent variable Control group –Similar in every way to experimental group but not exposed to independent variable Placebo group –Participants receive an inactive substance Over 75 percent of participants may correctly guess their position in this group based on effects Types of Groups in an Experiment

7. © Cengage Learning 2016 Design of the experiment –Single-blind design Participants unaware of purpose of research –Double-blind design Participant and individual working directly with the participant unaware of the experimental conditions Some variables cannot be manipulated –Example: child abuse –Correlational studies are appropriate Additional Controls in Experimental Research

8. © Cengage Learning 2016 Statistical analysis to determine correlation between variables Allow analysis of variables that cannot or should not be controlled Types of correlation –Positive correlation –Negative correlation –No correlation Correlational Studies

9. © Cengage Learning 2016 Possible Correlations Between Two Variables

10. © Cengage Learning 2016 Investigation that attempts to simulate real-life situation under controlled conditions Used when not possible to control all variables in real-life situations –Or when ethical, legal, or moral issues preclude other types of studies Analogue Studies

11. © Cengage Learning 2016 Behaviors and events are observed and recorded in their natural environment The main technique is observation –Sometimes with interviews or questionnaires Observers must be highly trained –Avoid disrupting the natural environment Provides no information about causality Difficult to control variables Field Studies

12. © Cengage Learning 2016 Most studies are nomothetic –Study large numbers of people collectively Idiographic study –In-depth study of one person –Used to examine a rare or unusual phenomenon Types of single-participant studies –Case study –Single-participant experiment Single-Participant Studies

13. © Cengage Learning 2016 Intensive study of one individual –Relies on clinical data Observations Medical and psychological tests Historical and bibliographic information Can determine characteristics, course, and outcome of a rare disorder Used to study therapeutic or diagnostic techniques Case Study

14. © Cengage Learning 2016 Some aspect of a person’s behavior is used as a control (baseline) for comparison with future behaviors Multiple-baseline study –Baselines on two or more behaviors or the same behavior in two or more settings are obtained prior to intervention Raises questions about external validity Single-Participant Experiment

15. © Cengage Learning 2016 A Multiple-Baseline Study

16. © Cengage Learning 2016 Methods for studying biological processes involved in mental illness –Endophenotypes –Twin comparisons –Genetic studies –Study of the epigenetic processes Biological Research Strategies

17. © Cengage Learning 2016 Endophenotypes: measurable characteristics –Characteristic must be heritable –Occur more frequently in affected families than in the general population –Examples: anatomical or chemical differences in the brain, eye-tracking irregularities Guide prevention and early treatment efforts The Endophenotype Concept

18. © Cengage Learning 2016 Monozygotic (identical) twins –Share the same DNA –Have different fingerprints –Develop more differences from one another as they age Fraternal twins –Share same childhood environments –Often used to evaluate hereditary versus environmental influences on development Twin Studies

19. © Cengage Learning 2016 Goal: determine whether a disorder follows a genetic pattern If disorder is genetically linked: –Individuals closely related to person with disorder (proband) more likely to display disorder Penetrance –Proportion of individuals with a particular genotype who manifest the phenotype Genetic Linkage Studies

20. © Cengage Learning 2016 Study of environmental factors that influence whether or not a gene is expressed Builds on idea that certain environmental factors have greatest impact during sensitive periods in development Epigenetic changes can leave an imprint on eggs or sperm –Affects traits inherited by future generations Epigenetic Research

21. © Cengage Learning 2016 The use of animal models is a frequent practice –Allows for better control of variables –Permits experimental procedures not practical to use on humans –Example: newborn mice separated from mothers resulted in different behavior, emotional development, and gene expression Researchers were able to pinpoint the occurrence of exact biological processes Using Animals in Biological Research

22. © Cengage Learning 2016 Examines rate and distribution of mental disorders in the population Prevalence –Percentage of individuals in targeted population with a particular disorder during a specific period of time Incidence –Number of new cases of a disorder that appear in an identified population within a specific period of time Epidemiological Research

23. © Cengage Learning 2016 Meta-analysis: simplified process of comparing numerous research findings –Published versus unpublished studies Increasing emphasis on evidence-based practice Concerted effort to reduce bias and misconduct Focus on locating biomarkers and endophenotypes for particular disorders Contemporary Trends and Future Directions

24. © Cengage Learning 2016 What methods do researchers use to study the causes of and treatments for psychopathology? How does biological research help us understand causes of abnormal behavior? Why is epidemiological research important in understanding mental illness? What are current trends in psychopathology research? Review