PSYC 351 Chapter 4

What three things should treatment decisions consider under Evidence-Based Practice?

(1) High-quality research such as RCTs; (2) clinician judgement and experience; (3) client culture, values, needs, and perspectives

What does 'internal validity' refer to, and which research design is considered the 'gold standard' for it?

Confidence that one thing causes another; randomized controlled designs are the gold standard

In a simple experiment testing 'CBT will reduce depressive symptoms,' what are the independent variable (IV) and dependent variable (DV)?

IV = CBT (manipulated by the experimenter); DV = depressive symptoms (expected to change as a result)

What's the difference between the experimental group and the control group?

The experimental group is exposed to the IV (e.g., CBT); the control group is similar in every other way but not exposed to the IV (e.g., placebo or another intervention)

Using the HAM-D depression scale (0-54 range) as an example, what's the difference between statistical significance and clinical significance?

A 3-point decrease may be statistically significant but not clinically meaningful, while moving from a 22 (moderate-severe) to a 14 (mild-moderate) is clinically significant — i.e., clinical significance is about how meaningful results are in a real clinical setting

What is the difference between a single-blind and a double-blind design?

Single-blind: participants are unaware of the study's purpose. Double-blind: both the participant AND the person working directly with them are unaware of the experimental conditions

Correlational studies can show that two variables are related, but what is their key limitation?

They do not explain the reason for the relationship (i.e., they can't establish causation)

What are the strengths and weaknesses of the case study method?

Strength: can reveal characteristics/course/outcome of a rare disorder; weaknesses: questionable generalizability, and data often reflects the investigator's theoretical bias

What is a 'base rate,' and why does it matter for interpreting research?

The natural occurrence of a phenomenon in the population studied; understanding base rates prevents overinterpreting correlations/causality and helps interpret symptoms within cultural context

What is a 'proband' in a genetic linkage study, and what is the overall procedure?

The proband is the identified person with the disorder; the procedure involves identifying the proband, tracing family psychiatric history, and formally assessing family members

What is an endophenotype? What are the 3 criteria for something to be considered an 'endophenotype'?

Measurable traits that indicate genetic pathways; Must be heritable, must be seen in family members without the disorder, and must occur more frequently in affected families than the general population

Genotype vs. phenotype

Carry a gene; observable manifestation (a disorder)

What is 'penetrance,' and is complete or incomplete penetrance the rule in mental disorders?

The proportion of people with a genotype who manifest the phenotype; incomplete penetrance is the rule in mental disorders

In twin studies, how do monozygotic (identical) and dizygotic (fraternal) twins differ in genetic material, and what does it mean if MZ twins are more similar on a trait than DZ twins?

MZ twins share the same DNA; DZ twins share about 1/2 their genetic material (like regular siblings). If MZ twins are more similar than DZ twins on a trait, that suggests a strong genetic influence

In epidemiological research, what is the difference between 'prevalence' and 'incidence'?

Prevalence = percentage of a population with a disorder during a specific period (e.g., people living with OCD in the past year); incidence = number of NEW cases appearing in a specific period (e.g., newly diagnosed with OCD in the past year)