Familial suicide behaviour: association with probands suicide attempt characteristics and 5-HTTLPR polymorphism

Objective: There is compelling evidence that a serotonergic dysfunction may play a major role in suicide behaviour and it has also been demonstrated that suicide is, at least partially, genetically determined. Thus, the serotonin-related genes are the major candidates. Previously a functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) was identified and the presence of the short allele (S) was found to be associated with a lower level of expression of the gene and lower levels of 5-HT uptake when compared with the long allele (L).The purpose of this study was to evaluate the association between family suicide behaviour history and probands' suicide attempt (SA) history, SA characteristics and 5-HTTLPR genotype. Method: We genotyped 237 probands (major depressed or schizophrenic patients) and used a semistructured interview to determine probands' SA characteristics and first- and second-degree family suicidal behaviour. Results: An association between suicidal family history and proband's SA but not with SA characteristics and probands genotype was found. Conclusion: Our results suggest that multiple biological and environmental factors underlie familial transmission of suicidal behaviour.