Task 5 Genes, stress, and emotionality

Question 1

5-HTTLPR

Answer 1

• polymorphism within promoter region of gene encoding the serotonin transporter (SERT)
• 5-HTTLPR has short (s) and long (L) allele
  –> S allele leads to decreased SERT expression compared to L allele
  –> S allele is associated with increased stress sensitivity, higher likelihood to develop PTSD and MDD: due to lower resilience in S allele carriers

Question 2

5-HTTLPR x Environment interaction

Answer 2

• 5-HTTLPR moderates the effect of environmental factors (childhood maltreatment, stressful life events) on risk of depression: ss allele carriers have a *higher risk of depression after being exposed to stressful life events or childhood maltreatment)

Question 3

Three-way interaction

Answer 3

• interaction between life events x neuroticism x 5-HTTLPR allele and effect on depression
• high trait neuroticism:
  a. more emotionally vulnerable to stress
  b. low expectations for self-efficacy
  c. less-adaptive coping strategies for stressful events
  d. most vulnerable to develop MDD

Findings:
- interaction between 5-HTTLPR and life events on depression is more powerful for high-impact events experienced by individuals with high-trait neuroticism
–> only individuals with high trait neuroticism and high impact of life events increased in depression scores when carrying S allele compared to LL allele

Question 4

Summary

Answer 4

5-HTTLPR x life events interaction on depression **may be conditional on cognitive vulnerability to attribute events as highly threatening*