GCSE Psychology 9-1

Psychology  9-1 GCSE -  3.2.1 - Caspi et al. (2003) Influence of Life Stress on Depression: Moderation by a Polymorphism in the 5-HTT Gene: Aims -  To investigate whether functional change in the 5HTT gene is linked to a higher or lower risk of depression in an individual. Method -  The researchers used an opportunity sample from a cohort of participants who were part of another longitudinal study. There were 847 participants of 26 years old and they were split into 3 groups, depending on the length of their alleles on their 5HTT transporter gene. Group 1 - Two short alleles, group 2 - one short and one long allele, group 3 - two long alleles. 1. Stressful life events occurring after the 21st birthday and before the 26th birthday were assessed using a life history calendar.  2. Post-year depression was assessed using the diagnostic interview schedule. 3. A correlation was tested between stressful life events and depression. Between the leng...