Hypothalamic-Pituitary-Adrenal Axis Hyperactivity Is Associated With Decreased Brain-Derived Neurotrophic Factor In Female Suicide Attempters

Introduction: Both decreased levels of brain-derived neurotrophic factor (BDNF) and hypothalamic-pituitary-adrenal (HPA) axis dysregulation may be involved in the pathophysiology of suicidal behaviour, as well as cognitive symptoms of depression. Pre-clinical and clinical studies have shown interactions between HPA-axis activity and BDNF, but this has not been studied in a clinical cohort of suicidal subjects. The purpose of this study was, therefore, to investigate associations between HPA-axis activity and BDNF in suicide attempters. Furthermore, this study examined the relationship between the HPA-axis, BDNF, and cognitive symptoms in suicidal patients. Since previous data indicate gender-related differences in BDNF and the HPA axis, males and females were examined separately.Method: Seventy-five recent suicide attempters (n=41 females; n=34 males) were enrolled in the study. The Dexamethasone Suppression Test (DST) was performed and BDNF in plasma were analysed. Patients were evaluated with the Comprehensive Psychopathological Rating Scale (CPRS) from which items Concentration difficulties' and Failing memory' were extracted.Results: Only among females, DST non-suppressors had significantly lower BDNF compared to DST suppressors (p=0.022), and there was a significant correlation between post-DST serum cortisol at 8 a.m. and BDNF (r(s)=-0.437, p=0.003). Concentration difficulties correlated significantly with post-DST cortisol in all patients (r(s)=0.256, p=0.035), in females (r(s)=0.396, p=0.015), and with BDNF in females (r(s)=-0.372, p=0.020).Conclusion: The findings suggest an inverse relationship between the HPA-axis and BDNF in female suicide attempters. Moreover, concentration difficulties may be associated with low BDNF and DST non-suppression in female suicide attempters.