Assigned Articles

Question 1

Bouchard

Answer 1

scientific question: “How do genetic differences affect psychological differences?”
data: 54 sets of adult monozygotic twins, two sets of triplets that were reared apart, and 274 sets of adult monozygotic twins reared together. The average age among the participants was 41; the reared-apart twins were separated after five months and separated for 30 years on average; all participants were mainly from the UK and the US.
Analytical approach: To study the reared apart and reared together, participants completed 50 hours of assessment, independently under supervision, that covered IQ, life history, a psychiatric interview, and sexual history. After this, a test is administered to measure their mental ability.
Findings: genetic factors are pivotal in behavior and general intelligence

Being raised in the same home is not essential for behavioral traits.

Question 2

Grove

Answer 2

Scientific Question: “mechanical and clinical methods, which one is more accurate?”
Design: To study this question, he used a meta-analysis study design. Meta-analysis is a statistical technique that combines the findings from individual studies.
Grove used data such as individual studies that predicted human behavior, made medical diagnoses, or assessed states and traits. Groves used a meta-analysis to compare the accuracy of clinical and mechanical prediction results because it would lead to more straightforward and concrete results.
Findings: that mechanical prediction performs as well or better than clinical.

Question 3

Kendler

Answer 3

Question: To what degree do stressful life events cause major depression?

Data: They bring data from over 15 classes of stressful life events and the onset of major depression over a 1-year period in female twins. The sample consists of 24,648 person-months and 316 onsets of major depression. The stressful events were rated on threat and dependence (the degree to which the stressful life event could have resulted from the respondent’s behavior)

the analytical approach used: co-twin control analysis

take home findings: Stressful life events have a substantial causal relationship with the onset of episodes of major depression.

Question 4

Colodro-conde

Answer 4

question: Are adults with higher genetic risk for schizophrenia more likely to live in urbanized and populated areas than those with lower risk?

Data: They brought in four large samples of genotyped individuals of European ancestry older than 18 years with known addresses in Australia, the United Kingdom, and the Netherlands. They also brought in 5894 twins and 15544 participants from the QIMR sample.

Analytical approach: a cross-sectional study, twin models, polygenic scores, and mendelian randomization

Take home findings: participants living in more densely populated areas had a higher genetic loading for schizophrenia. individuals with increased genetic risk tend to live in urban/dense areas and suggest the need to refine the social stress model for schizophrenia by including genetics as well as possible gene-environment interactions.

Question 5

Saunders

Answer 5

Question: what are the longitudinal effects and environmental moderation of ALDH2 and ADH1B gene variants on substance use?

Data: They bring in 412 genotyped adopted individuals of East Asian ancestry between the ages of 14 and 40.

Analytical approach: an adoption study with a longitudinal design

Take home findings: found strong associations between alcohol frequency, quantity, and maximum drinks and ALDH2, but not ADH1B. They also found that the magnitude of the ALDH2 protective effect increased with age, especially for maximum drinks. Finally, there was no strong evidence of associations between ALDH2 status and tobacco, marijuana, or illegal drug use. This is contrary to expectations if alcohol serves as a gateway to the use of other drugs.

Question 6

Kreuger

Answer 6

question: First, what is the etiologic basis for the phenotypic externalizing factor? Second, are there etiologic factors that distinguish among specific externalizing disorders? Third, are disinhibitory personality traits part of the externalizing spectrum?

Data: 1,048 male and female seventeen-year-old twins.

Analytical Approach: 1,048 male and female seventeen-year-old twins.

Take-Home Findings: The externalizing spectrum here is highly heritable and is thought to be the etiological factor that gives rise to high comorbidity across the different disorders.