Interaction of Child Maltreatment and 5-HTT Polymorphisms: Suicidal Ideation among Children from low-SES Backgrounds

OBJECTIVE: To investigate whether genotypic variation of the serotonin transporter gene-linked promoter region (5-HTTLPR) moderates the effect of maltreatment on suicidal ideation in school-aged children. METHODS: Eight hundred and fifty low-income children (478 maltreated; 372 non-maltreated) provided DNA samples and self-reported depressive and suicidal symptoms. Genotypes of 5-HTTLPR (s/s or s/l vs. l/l) were determined by fragment analyses. RESULTS: Higher suicidal ideation was found among maltreated than non-maltreated children; the groups did not differ in 5-HTTLPR genotype frequencies. Children with one to two maltreatment subtypes and s/s or s/l genotypes had higher suicidal ideation than those with the l/l genotype; suicidal ideation did not differ in non-maltreated children or children with three to four maltreatment subtypes based on 5-HTTLPR variation. The results were applicable to emotionally maltreated/neglected and to physically/sexually abused children. Gene-environment interaction was not found for depressive symptoms. CONCLUSION: The protective effect of the 5-HTTLPR l/l genotype on suicidal ideation was limited to maltreated children experiencing fewer subtypes.