Epidemiology and Research Methods Flashcards
What is epidemiology?
The study of prevalence, distribution, and risk factors of psychological disorders within populations.
Define prevalence in the context of psychological disorders.
The percentage of people in a population who have a disorder at a specific time point.
What are the different types of prevalence measurements?
- Point prevalence
- Past-month/year prevalence
- Lifetime prevalence
What is incidence in epidemiology?
The percentage of people who develop a disorder for the first time during a given period.
What is a risk factor?
A correlate linked to a disorder’s occurrence or a predictor that contributes to disorder development.
What is etiology in psychology?
The scientific study of how something develops, focusing on underlying factors causing illness.
Explain equifinality.
Multiple different factors can lead to the same outcome.
What does multifinality mean?
A single cause can lead to multiple different outcomes.
Define final common pathway.
A theoretical mechanism where multiple causes converge on the same outcome.
What is the environmental model of mental disorders?
Mental disorders can develop due to environmental factors, particularly early life experiences.
What is the ‘Schizophrenogenic Mother’ hypothesis?
Suggests that inconsistent parenting from mothers could cause schizophrenia.
What are the implications of genetics in mental disorders?
- Genes are not deterministic
- Most genes are probabilistic
- Psychopathology is polygenic
What does the diathesis-stress model explain?
How mental disorders develop from an interaction between vulnerability and external stressors.
What is a vulnerability marker?
Helps identify individuals at risk for a disorder before its onset.
Differentiate between case-control and cohort studies.
- Case-Control Study: Compares those with a disorder to those without.
- Cohort Study: Follows a large sample over time.
What is the goal of family studies in genetic epidemiology?
To determine whether a disorder runs in families and assess patterns of inheritance.
What are the key findings from family studies?
- Many disorders run in families
- Subthreshold symptoms can exist
- Coaggregation of related disorders
What is the purpose of adoption studies?
To examine how genetic risk interacts with a low-risk environment for a disorder.
What is the ACE model in twin studies?
- A: Additive Genetic Effects
- C: Common Environment
- E: Unique Environment
What are gene-environment correlations (rGE)?
Interactions between genes and environments that influence individual traits.
Define passive rGE.
The environment shaped by the same people who provide the genes.
What is evocative rGE?
A person’s traits elicit specific responses from the environment.
Explain active rGE.
People actively select environments that match their genetic traits.
What is one limitation of twin studies?
MZ twins often share a placenta, creating a more similar prenatal environment than DZ twins.
True or False: Heritability estimates indicate genetic determinism.
False
What does rGE stand for?
Gene-Environment Correlation
How can rGE lead to overestimation of genetic effects?
Heritability estimates may falsely attribute environmental influences to genetics alone.
Provide an example of how rGE might work.
A child with genes for high intelligence raised in an intellectually stimulating environment.
What is Gene-Environment Interaction (G×E)?
The effect of the environment depends on an individual’s genetic makeup.
What is an example of G×E?
Two kids experience high family stress; one develops depression due to genetic vulnerability, the other does not.
Define Single-Gene Transmission.
A single gene determines the phenotype of the child.
What is a key expectation of Single-Gene Transmission in psychiatric disorders?
50% of first-degree relatives would also have the disorder if caused by a single dominant gene.
What is the problem with Single-Gene Transmission in psychiatry?
No psychiatric disorders show this pattern of inheritance.
Define Polygenic Transmission.
Most psychological traits and disorders are influenced by multiple genes.
What are characteristics of Polygenic Transmission?
- Multiple genes contribute to a disorder
- Additive effects
- Interactive effects
What is Missing Heritability?
Heritability estimates suggest strong genetic influences, but specific genetic mechanisms are not fully identified.
Why is there Missing Heritability?
- Common genetic variants explain small proportion
- Polygenic complexity
- Gene-environment interactions
- Rare genetic variants
What was the hypothesis of the cohort study on psychopathology?
Genes alone don’t cause disorders; they create vulnerabilities requiring environmental catalysts.
What was the key finding regarding the 5-HTT gene and childhood abuse?
Presence of at least one short allele increases vulnerability to depression under severe abuse.
What does epigenetics refer to?
Regulation and expression of genes without changes in the DNA sequence.
What was the main finding of Michael Meaney’s rat study?
Maternal care influenced stress regulation and cortisol levels in pups.
What do endophenotypes represent?
An intermediate biological or cognitive marker linking genetic variation to observable traits.
List the criteria for identifying an endophenotype.
- Segregate with the illness
- Be heritable
- Not state-dependent
- Co-segregate with illness in families
- Be present at a higher rate in affected families
- Be measurable and specific
Why are endophenotypes important?
They help understand genetic factors in psychiatric disorders and may improve detection and prevention.
True or False: No known endophenotype is completely specific to a single disorder.
True
