Even after the age of 70, people prone to feelings of anxiety, worry, distress and insecurity face a risk for a first lifetime episode of clinically significant depression, according to a unique study led by a University of Rochester Medical Center researcher.
"We assume that because depression has not developed for people with these personality traits by the age of 70 that it won't develop," said Paul R. Duberstein, Ph.D., professor of psychiatry who led the study. "But even in older adulthood, these traits confer risk. Presumably something about aging helps take down the façade or destroys the protective sheath that has kept them from significant depression."
The findings from the prospective study, the first of its kind, are published in the May issue of the journal Psychological Medicine.
Having a working-class background also may place older adults at heightened risk for depression, particularly prior to the age of 80, the study found. Consistent with previous research, women were found to be at greater risk than men. The study enhances the understanding of late-life depression and could aid in the identification and treatment of people at risk.
"The findings suggest that long-standing personality traits can predict onset of depression into older adulthood," said Duberstein, who is director of the Laboratory of Personality and Development at the Medical Center.
The researchers utilized data from a multi-disciplinary study of 70-year-old residents of Göteborg, Sweden, that began in 1971 to gain a greater understanding of aging and age-related disorders.
Because most people in Sweden receive their health care through a public health system, the study had access to decades of medical records. Data collection also involved physical and mental health examinations and a social assessment. After the initial test, participants were examined over a 15-year period at the ages of 75, 79, 81, 83 and 85.
For the current study, researchers eliminated people at age 70 with dementia and other psychiatric disorders. In all, the records of 275 people were analyzed. There were 59 cases of first lifetime episodes of depression after the age of 70.
"Although we are aware of no research on how people who are highly distress prone manage to stave off clinically significant depression, protective factors might play a role," the study authors state. "Candidate protective factors include close personal relationships, rewarding occupations or meaningful hobbies, physical vigor and vitality, economic independence, and spiritual well-being. Processes related to aging might inexorably erode some of these protective factors."
The researchers urge more study of the relationships between personality, age and first lifetime episodes of depression.
"This is a particularly important issue for older men, given their high suicide rate in many Western countries, and the observation that they often take their lives in the midst of a first lifetime episode of depression," the researchers state.
In addition to Duberstein, the authors of the Psychological Medicine article are Sigurour P. Pálsson of the Division of Psychiatry, Landspitali University Hospital, University of Iceland, and Margda Waern and Ingmar Skoog, of the Institute of Neuroscience and Physiology, Department of Psychiatry, Sahlgrenska University Hospital, Göteborg University.
The research was supported in part by grants from the United States Public Health Service, the Swedish Research Council and the Swedish Council for Working Life and Social Research.