Background:
A genetic variation within the promoter region of the serotonin transporter (5-HTT) gene has been found to moderate the effect of stressful life events on onset of major depression (Caspi et al. 2003; Wilhelm et al. 2006). This paper examines for observable characteristics underlying the genetic liability to depression following stressful events associated with differing 5-HTT genotypes within two study samples.
Method:
Study 1 – ‘diabetes study’. Commencing in July 2006, patients presenting to a hospital-based diabetes clinic were recruited. Participants provided data on psychiatric diagnosis, personality traits (NEO) and coping styles (COPE), as well as provided saliva samples for genetic analysis. Study 2 – ‘teachers cohort study’. Between 1978 and 1998, episodes of major depression, life events, coping behaviours and trait anxiety measures (EPQ, TCI) were recorded at 5 yearly intervals. In 2003, blood or saliva samples were collected for genetic analysis.
Results:
Associations between the 5-HTT gene and candidate phenotypes (trait anxiety and coping styles) were examined using preliminary data from the diabetes sample (anticipated n > 100). For the teachers cohort study, no associations between the 5-HTT genotype and trait anxiety were found for those who provided genetic material (n = 128). There were, however, significant differences on the coping behaviours used by differing genotype groups when under stress.
Conclusions:
These findings raise the possibility of a genetic disposition to emotional reactivity to stressors that may predispose individuals to use different coping strategies. Replication of these findings will be examined within the diabetes sample.
