Volumetric Analysis of the Hypothalamus, Amygdala and Hippocampus in Non-Suicidal and Suicidal Mood Disorder Patients - A Post-Mortem Study

In recent years, the hypothalamus, amygdala and hippocampus have attracted increased interest with regard to the effects of stress on neurobiological systems in individuals with depression and suicidal behaviour. A large body of evidence indicates that these subcortical regions are involved in the pathogenetic mechanisms of mood disorders and suicide. The current neuroimaging techniques inadequately resolve the structural components of small and complex brain structures. In previous studies, our group was able to demonstrate a structural and neuronal pathology in mood disorders. However, the impact of suicide remains unclear. In the current study we used volumetric measurements of serial post-mortem sections with combined Nissl-myelin staining to investigate the hypothalamus, amygdala and hippocampus in suicide victims with mood disorders (n = 11), non-suicidal mood disorder patients (n = 9) and control subjects (n = 23). Comparisons between the groups by using an ANCOVA showed a significant overall difference for the hypothalamus (p = 0.001) with reduced volumes in non-suicidal patients compared to suicide victims (p = 0.018) and controls (p = 0.006). To our surprise, the volumes between the suicide victims and controls did not differ significantly. For the amygdala and hippocampus no volume changes between the groups could be detected (all p values were n. s.). In conclusion our data suggest a structural hypothalamic pathology in non-suicidal mood disorder patients. The detected differences between suicidal and non-suicidal patients suggest that suicidal performances might be related to the degree of structural deficits.