An additional reason for the difference between the meta-analyses of the different stressor subgroups may be the nature of the stressors studied. Most of the specific stressor studies focused on chronic stressors while the SLE studies focused on acute stressful life events. Interestingly, three studies have explicitly looked at both acute and chronic stressors in their cohorts and all three have found that the 5-HTTLPR moderating effects were stronger for chronic stressors 10, 16, 45. Future primary studies that are able to systematically test genetic moderation effects on different types of stressors will be valuable in furthering our understanding of the specific characteristics of stressors that are moderated by 5-HTTLPR and other genetic loci important in stress response.
