Resilience Mediates the Influence of a Polymorphism in the Serotonin Transporter Gene on the Relationship between the Burden of Chronic Illness and Depression

Genetic Variants Associated With Resilience in Human and Animal Studies

“…The most frequently investigated polymorphism ( n = 18) was the 5-HTTLPR (serotonin transporter linked polymorphic region) which is located in the promoter of the human serotonin transporter gene ( SLC6A4 ). Out of these studies, 12 found the L′/L′ allele to be associated with resilience ( 37 , 59 , 102 , 114 , 117 , 126 , 130 – 134 , 144 ) and four studies found the S or S′ allele to be associated with resilience ( 103 , 104 , 123 , 145 ), and one study found that only haplotypes of the serotonin transporter were associated with resilience, the single genetic variants were not ( 115 ). There are a several factors that might contribute to these inconsistent findings.…”

“…This is the triallelic classification system. 12 of the studies excluded the SNP rs25531 from their analyses ( 37 , 102 , 103 , 114 , 115 , 117 , 126 , 130 , 132 , 134 , 144 , 145 ), and five studies genotyped for rs25531 and recoded accordingly ( 59 , 104 , 123 , 131 , 133 ). One study found a significant association with the biallelic classification system, but not with the triallelic ( 37 ), and another study excluded the results of the triallelic system due to a low number of participants carrying the L G allele ( 102 ).…”

Association between resilience and a functional polymorphism in the serotonin transporter (SLC6A4) gene: A meta-analysis

“…These results should be interpreted with caution because of the fact that it was not possible to carry out several comparisons, due to the lack of availability of relevant data in the included articles. In addition, it was not possible to include several other studies in our analysis, taking into account that key data were missing on them (Agnafors et al, 2017[ 1 ]; Amstadter et al, 2012[ 2 ]; Beaver et al, 2011[ 5 ]; Delis et al, 2017[ 14 ]; Gibbons et al, 2012[ 19 ]; Hemmings et al, 2013[ 23 ]; Resnick et al, 2019[ 36 ]). Therefore, we suggest that all studies analyzing possible effects of genetic variations associated with resilience should report all scores and measures stratified by genotypes and alleles; this will improve further analyses.…”