There is evidence that proneness to experience psychological distress is a risk factor for Alzheimer's disease (AD). In the present study, an attempt is made to examine the possible association between stressful events and cognitive impairment of the elderly, based on a sample of 1271 patients (500 male, 771 female) diagnosed with dementia according to the DSM-IV criteria and 140 age- and gender-matched cognitive healthy subjects. All patients were recruited from the Memory and Dementia Outpatient Clinic of the 3rd University Department of Neurology in "G. Papanikolaou" General Hospital, Thessaloniki, and examined over a period of 7 years. The majority of patients reported a history of a stressful event before the onset of dementia (n=990, 77.9%), while fewer patients reported insidious onset (n=281, 22.1%). The most frequently reported event was the announcement of a life threatening disease (n=472, 37.1%), followed by problems within the family (n=157, 12.4%), spouse death (n = 100, 7.9%), death of a sibling or other beloved person (n=77, 6.1%). Only 55% of the control subjects encountered stressful events, which is significantly different from the percentage of the study group. Our results demonstrate that a stressful event in the elderly could potentially trigger a cognitive decline.