Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis function is associated with suicidal behaviour and age-associated alterations in HPA axis functioning may render elderly individuals more susceptible to HPA dysregulation related to mood disorders. Research on the role HPA axis function in suicidal behaviour in elderly mood disorder patients is sparse.The study sample consisted of 99 depressed elderly inpatients 65 years of age or older admitted to the department of Psychiatry at the Karolinska University Hospital between 1980 and 2000. 24 % of patients had attempted suicide just before admission. The hypothesis was that elderly mood disorder inpatients who fail to suppress cortisol in the dexamethasone suppression test (DST) are at higher risk of suicide.

During a mean follow-up time of 17 years (range 6-25.5 years), six suicides were identified from the death certificates. The DST non-suppression distinguished between suicides and survivors in elderly depressed inpatients and the suicide attempt at the index episode was a strong predictor for suicide. Additionally, the DST non-suppression showed higher specificity and predictive value in the suicide attempter group. Due to age associated alterations in HPA axis functioning, the optimal cut-off for DST non-suppression in suicide prediction may be higher in elderly mood disorder inpatients.