Men with a history of depression long before the onset of any memory or other cognitive problems have a substantially higher risk of developing dementia, especially Alzheimer’s disease (AD), later in life, a study indicates. This risk is not observed in women.

Dr. Gloria Dal Forno, of University Campus BioMedico and Associazione Fatebenefratelli per la Ricerca, Rome, Italy, and colleagues examined the association between premorbid symptoms of depression and the development of dementia and AD over a period of 14 years in 1357 subjects enrolled in a study on aging.

Researchers assessed the frequency and severity of depressive symptoms every 2 years using standard instruments.

A total of 49 cases of dementia were diagnosed among women during the study period. Of these, 40 represented AD. A total of 76 men were diagnosed with dementia, of which 67 were AD.

The risk of dementia, especially AD, was significantly increased with premorbid depressive symptoms only in men. The risk was approximately two times greater in those with a history of depression than for those without a history of depression, and was independent of the presence of vascular disease.

“The prevalence and clinical manifestations of both AD and depression differ in men and women,” Dal Forno noted in an interview with Reuters Health.

“We know that male and female brains have anatomical and functional differences and are exposed differently to sex hormones throughout life, hormones known to have effects on both depression and AD,” she noted.

“As a consequence, male and female brains might react to conditions causing or enhancing a disease quite differently, which seems to be precisely what we found in this investigation.”

Given the prevalence of depression and increasing longevity worldwide, “clearly the public health and economic implications are significant,” the researcher added.

Furthermore, “Prevention of depressive disorders and aggressive as well as long-term treatment of depression may impact on the epidemiology of dementia,” she added. “This is particularly relevant in men since they generally are less likely to admit to symptoms of depression and to seek treatment.”

SOURCE: Annals of Neurology March, 2005.