Caspi et al. (2003) - Study | Psychology

IB Questions

• Genetics and Behaviour - Genes

Name of the Researcher

Caspi

Publication

2003

Aim

To investigate if different alleles of the 5 HTT-gene exhibits varying vulnerability to depression in relation to stress.

Research Method

Quasi-Experiment

Procedure and Participants

Participants - 847 participants from New Zealand who has had their mental health assessed until 21 years of age.

1. Participants were divided into three groups:

   a. Two Short Alleles

   b. One Long and One Short Allele

   c. Two Long Alleles

2. They were asked to fill out a questionnaire with 14 questions about stressful life events concerning health, finance, employment and relationship.

Results

Participants who had a copy of one or more short alleles displayed more symptoms and suicidal ideation in response to stress.

Conclusion

Inheriting a copy of the short allele of 5-HTT in combination with a stressful environment causes a higher vulnerability to depression.

Strengths

+ Holistic Approach (Gene and Stress)

Limitations

- Cause-and-Effect can’t be inferred.
- Inconclusive Findings