Effects of acute psychosocial stress exposure on endocrine and affective reactivity in college students differing in the 5-HTTLPR genotype and trait neuroticism

Enhanced stress vulnerability has been implicated in the pathogenesis of affective disorders. Although both genetic (5-HTTLPR) and cognitive (neuroticism) factors are known to increase stress vulnerability, no experimental study has investigated the interaction between these two factors on psychobiological reactivity following acute stress exposure. This study used a balanced experimental design to examine the interaction between the 5-HTTLPR genotype and trait neuroticism in neuroendocrine and affective stress responses. From a large group of 771 students, 48 carriers of the short/short (S/S) allele and 48 carriers of the long/long (L/L) allele with the lowest and the highest neuroticism scores (77 females, 19 males; mean age?±?SD: 20.6?±?2 years) were selected and exposed to an acute psychosocial stressor. Mood was assessed before and after the stressor, and salivary cortisol concentrations were measured before and at 20, 30, and 60?min after stressor onset. Acute stress increased salivary cortisol concentration regardless of either 5-HTTLPR genotype or neuroticism, but it caused a less profound negative mood change in L/L compared to S/S-allele carriers with the lowest neuroticism scores. The 5-HTTLPR genotype influences affective reactivity to acute stress conditional upon neuroticism, improving resilience to acute stress in L/L-allele carriers if they do not already possess high cognitive-affective (neuroticism) vulnerability.