Estresse precoce e comportamento suicida em pacientes bipolares: estudo de associação com polimorfismos dos genes da COMT e do BDNF

Abstract

The Bipolar Disorder (BD) is a psychiatric disorder associated with high rates of suicide attempts. Early life stress (ELS) one of several factors that contribute to the appearance of Suicidal Behavior and negatively influences the course of BD. There are many articles that confirm this association. We selected 47 patients with BD I, attending the Affective Disorders Clinic of the Residence of Psychiatry, Federal University of Minas Gerais (UFMG). In addition, 48 randomly selected controls by sex, age and education. Were fulfilled Hamilton depression scales, the Young Mania Scale, and a structured psychiatric interview (MINI PLUS 5.0). ELS was assessed by questionnaire on the Childhood Trauma Questionnaire(CTQ) and suicidal behavior by Beck's Suicide Scale, and the attempt lethality by Becks Lethaliy Scale. Genetic polymorphisms of COMT and BDNF were assessed by PCR. Statistical analyzes were performed using Kolmogorv-Smirnov test, the Student t test or the Mann Whitney U and the chi-square (X2) Statistical analyzes were performed using the genetic program unphased 3.0.12. Among patients with BD were divided in groups with and without ELS and groups with and without suicidal behavior there were no significant differences in any variable studied. No association was found between the allelic or genotypic SNP studied for COMT and BDNF genes with suicidal behavior and ELS. We observed aslight tendency to the higher frequency of the heterozygous genotype GA in patients without Stress Early with suicidal behavior (p = 0.06). In conclusion, this study corroborates the notion that Suicidal Behavior is the result of complex interactions between multiple variables, including genetic factors. Independent replications in larger samples and further investigation on the role of ELS in this intricate network are necessary.