Approaches to Abnormality Flashcards
Outline and evaluate the family-risk method of genetic research.
Family-risk method: Large samples of relatives of index cases or probands. However, correlation =/= causation. Other variable: environmental impact of being raised in a psychopathological home.
What are the limitations of the genetic approach to abnormality?
Unfortunately, Mendelian inheritance is rarely, if ever, sufficient in explaining any aspect of human characteristics or behaviour. Human genetics, especially in psychopathology is extremely complex, involving polygenic mutations, codominance, partial dominance. Also need to take everything else into account- never 100% concordance.
Outline and evaluate the twin study method of genetic research.
Uses MZ (identical) and DZ (fraternal) twins. Concordance rate computed. If MZ>DZ then genes might have a role. However, may not be exposed to the same environmental conditions (MZ twins more similar environment than DZ twins; Joseph, 2004). Also, differences in identical twins assumed to be the result of the environment may be producd by gene mutations or chromosomal errors in mitosis or late in gestation. They also don’t provide information about genetic transmission, but rather genetic influence that is inferred from concordance rates (Bentall, 2004).
What are the three method of adoption studies?
Foster family approach: Uses index cases- and measures the adoptive home with one set of children having a biological parent with the disorder.
Cross-fostering approach: Children placed in foster homes that have one disordered foster parent (compare to foster family approach, reducing environmental confounds, Bentall 2003).
Predictive studies: Identifies high-risk children and one biological parent manifesting the disorder and follows over time.
