Depresyon etyopatogenezinde, semptomatolojisinde ve tedavisinde etkili genler ve gen-çevre etkileşimi


Tuğ E., Arısoy Ö.(Yürütücü)

Yükseköğretim Kurumları Destekli Proje, 2009 - 2011

  • Proje Türü: Yükseköğretim Kurumları Destekli Proje
  • Başlama Tarihi: Şubat 2009
  • Bitiş Tarihi: Şubat 2011

Proje Özeti

Across the life span, stressful life events influence the onset and cause of  depression. Diathesis-stress theories predict that individuals’ sensitivity to stressful life events depends on their genetic make-up. A functional polymorphism in the promoter region of the serotonin transporter gene was found to moderate the influence of life events on depression. Caspi et al (2003), showed that individuals with one or two copies of the short allele of the serotonin promoter polymorphism exhibited more depressive symptoms in relation to stressful life events than individuals homozygous for the long allele.  Our aim in this study was to retest if serotonin transporter polymorphism was associated with stressful life events and depression in Turkish population. Methods: 70 patients with major depression (MD) and 55 age-sex-education matched healthy controls were evaluated with SCID-I, Hamilton depression rating scale (HDRS), stresful life events and childhood trauma questionnaire and temperemant and character inventory (TCI). Results: Number of stressful life events in the preceding year  and their distress and adaptation scores were significantly higher in the MD group. Likewise; emotional abuse, emotional neglect and physical neglect  scores in childhood were also significantly higher in MD group. For TCI; novelty seeking and harm avoidance scores were significantly higher but self-directedness scores were significantly lower in the MD group. But, there were no differences in terms of either biallelic or triallelic serotonin transporter genotyping between the two groups. In spite of this, Beck depression inventory score, emotional abuse and emotional neglect scores were found to be significantly higher in the SS genotype group compared to LS an LL groups, although no difference could be found between the 3 genotype groups in terms of number of stresful life events in the preceding year.  Regression analysis revealed that number of stressful life events in the preceding year and their distres score, emotional abuse, emotional neglect and physical neglect scores predicted HAMD score while serotonin transporter genotype did not have a predictor effect. Conclusion: This is the first replication study from Turkey. Although we could not find a difference in terms of serotonin transporter genotype, we showed that the moderating effect of serotonin transporter polymorphism was greater for childhood trauma than for stresful life events just before the onset of depresssion like in other gene-environment interaction studies in major depression (1,2). These findings might suggest an influence of serotonin transporter polymorphism on serotonin transporter levels at an earlier phase of life, with the possibility of a disruption of normal maturation of certain neural networks which have an influence upon risk of depression independent of the current state of serotonin function (3)