There are about 30,000 suicides per year in the US and is predominant among the young and geriatric (75+) populations. Suicide is a symptom rather than a disease and there are a number of risk factors such as depression, alcohol and drug abuse, early life trauma, family history, hopelessness, abnormal neurobiology, impulsive-aggressive behavior, conduct adjustment disorder, stress and contagion-copy cat cluster. The last few of these are predominantly seen in teenage populations which are also characterized by the fact that they are non-responsive to tricyclics but do respond to SSRIs.
Dr Pandey's group studied post mortem brain samples of depressed suicide victims and found that Protein and mRNA expression of Glucocorticoid receptors (GR) were lower in the prefrontal cortex(PFC) and amygdala. The same was true for Corticotropin Releasing Factor Receptor 1 (CRF-R1) and CRF Binding Proteins. Overall, dysregulation of the Hypothalamo-Pituitary-Adrenal (HPA) axis was seen to be related to altered expression of CRF and GR in PFC and amygdala. Interestingly, there was no change seen in the hippocampus. This could be because the sample population was young and perhaps the hippocampi had not yet been compromised.
In addition to the HPA axis, pro-inflammatory cytokines such as IL-1, IL-6, and INF-a were found to be increased and BDNF expression was decreased in depressed suicide victims.