Variability in the Effect of 5-HTTLPR on Depression in a Large European Population: The Role of Age, Symptom Profile, Type and Intensity of Life Stressors
Fig 1
5-HTTLPRxRLE interaction, with PLINK (left column) and Bayesian (right column) analyses.
LR+: likelihood ratio of emergence of the disease; BSI: Brief Symptom Inventory; BSI-DEP: BSI depression score; BSI-ANX: BSI anxiety score; DEP: lifetime depression; RLE: recent negative life events (in the last year). The three categories of RLE are: low = 0–1, medium = 2, high = 3 or more. Numbers in groups: low RLE: ss = 292, sl = 746, ll = 480; medium RLE: ss = 82, sl = 207, ll = 144; high RLE: ss = 51, sl = 146, ll = 134. Standard errors of means are displayed in case of continuous variables (left column). Right column figures display outlines of posterior distributions of Bayesian Odds Ratios of 5-HTTLPR ss versus ll genotype with respect to DEP, BSI-DEP (severe vs. low), and BSI-ANX (severe vs. low). Subsets according to RLE categories (low, medium and high) were analyzed individually. Curve flatness refers to the number of possible models, each with a different odds ratio. An odds ratio greater than one represents a risk for the given phenotype. 1A. Logistic regression analysis showed that having the more s alleles increased the risk of DEP with increasing number of RLE. 1B. Regarding DEP there is a clear difference between subjects with low RLE (with a Bayesian Odds Ratio close to 1) and subjects with medium or high RLE (where the effect of ss genotype is stronger). 1C. As in case of DEP: having the more s alleles also increased BSI-DEP with increasing number of RLE, using linear regression analysis. 1D. As in case of DEP: effect of ss genotype on BSI-DEP is negligible in the low RLE group, but higher in the medium, and especially high in the high RLE group. 1E. In contrast to depression phenotypes: linear regression analysis showed that carrying the more s alleles increased BSI-ANX without interaction with RLE. 1F. In contrast to depression phenotypes, ss genotype represents a risk for BSI-ANX irrespective of RLE group.