Lecture #04

Objective:
• Scientific Method
• Threats to findings
• Adequacy of findings
• Research strategies/clinical trials
• Statistical vs Clinical Significance
• Range of primary foci o Description (DSM) o Causation (psychopathology) o Intervention/outcome (one of primary reasons for the study of abnormal psychology)

Historical Perspectives revisited: Integrative models
Diathesis-Stress
• Basic argument: we are all born with a physiological vulnerability to the development and expression of mental health disorders
• Multiple genetic factors
• We have to a greater or lesser extent, that genetic vulnerability
• Person A vs B vs C
• Person A may have a small amount of genetic vulnerability, B has more and C has the most
• Each person must experience a certain amount of “stress” before they will express a mental health disorder
• Stress is psychosocial (or environmental) in nature; stress is not constant  it’s fluid, ebbs and flows
• Risk factor is biological in nature
• Diathesis may be related to interpersonal factors; or stress is related to biological factors
• Additive model; certain amount of vulnerability and stress  then does it reach the threshold for mental health disorder or not
• Risk of expression influenced by stress
• Some pathology factor that we can identify that produces this form of deviance dysfunction; not of the models that he introduce can do an adequate job of explaining all of the abnormal pathologies; better to take an integrative look; the most basic of the integrative models is the diathesis-stress model
Reciprocal Gene-Environment
• More dynamic process than diathesis
• Assumes that the traits associated with our genetic endowment that may lead us to experience stress
• People who like risk will seek activities that expose them to risky situations which would expose them to more environmental stressful events.
• We still have an additive process, but it’s our traits that make us more or less likely to expose ourselves to stress

Introduction: Research … Scientific method
Identify / define problem of interest
Gather background information
Develop strategy for testing hypothesis
Conduct study, review findings
Refine hypothesis and continue process

Range of research objectives
Description
Causation
Intervention / treatment outcome

Managing “random error”

Threats to findings
• Imprecision of measures of interest o Ex. Using a ruler to measure barometric pressure o Use a measure appropriate to the measure of thing of interest
• Error

Validity revisited
Internal Validity (IV)
• The independent variable causing the dependent variable to change
• Can enhance IV by random assignment of groups, use of control groups (ensure that a group of subjects is exposed to everything except the active ingredient), blind studies (double blind  experimenter and participant don’t know who is obtaining the active ingredient and who is obtaining the placebo)
• Treatment interventions use placebo effects (make sure participants are blind to the treatment they are exposed to)
External Validity (EV)
• How well findings relate to “real world”
• Enhance EV by ensuring that samples in our study relate closely to the sample we would like our findings to apply to

Research strategies: Duration
Cross-sectional
• study the relationships/effects at one point in time
• only examine a participant once
Longitudinal

Single-subject research
• Case Studies: detailed exploration of rare events (ex. P. Gage)
• Help generate causal hypotheses
• Allows test of causal hypotheses
• Difficult to generalize to others

Multiple Subject Observational Research
• Population Studies (e.g. epidemiological NCS-R)
• Note: Prevalence is always greater than incidence
• Multiple group studies: Correlation
• Correlational research style o defining characteristics of interest o Question is: is the correlation meaningful?
 Negative correlation
 Zero correlation
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