Interestingly, and in contrast to previous results, we could only demonstrate an effect of recent life events in our interaction models, but not of childhood maltreatment [10,11,14,38]. As a possible explanation for the discrepancies concerning 5-HTTLPR and different types of life events it has been suggested that the role of childhood adversity may be more specific to recurrent or chronic depression than to single depressive episode occurrences [38,39]. This is in line with the stress sensitization hypothesis, which suggests that childhood adversity leads to increased vulnerability to adult stressors and thus more psychopathology, especially increased risk for depression [40]. In our study, childhood adversity sensitized young subjects (≤30) to recent negative life events, such that even in the case of medium number of RLE 5-HTTLPR showed high relevance in the depression-related multivariate phenotype. However, we could not demonstrate a similar sensitization effect in the older group (>30).
