Psychological symptoms in middle age may rise dementia risk

Psychological symptoms in middle age increase the risk of developing dementia in old age, according to a new population-based study.

The study carried out collaboratively by the Finnish Institute for Health and Welfare (THL), the University of Helsinki and the University of Eastern Finland demonstrated that the risk of dementia is one-fifth higher in people who report more perceived stress or depression, nervousness or exhaustion, said the THL in a press release on Tuesday.

The development of memory disorders is a gradual process affected by a number of factors at different stages of life.

Diagnosis of depressive disorder is considered a risk factor for dementia.

Prior research has suggested that even milder symptoms of psychological distress increase the dementia risk.

However, these studies have included either a small cohort of patients with dementia or a short follow-up period. Consequently, the studies have been unable to reliably distinguish between actual risk factors and the prodromal symptoms caused by changes in brain that develop before the clinical diagnosis of memory disorder.

The new findings published in the JAMA Network Open journal indicate that psychological distress symptoms increase the risk of dementia. This does not appear to be explained by the prodromal symptoms of memory disorders.

It was found that symptoms of depression, exhaustion or nervousness reported even as early as 45 years of age had a significant association with to a subsequent risk of dementia.

The study encompassed about 68,000 Finns who participated in the National FINRISK study from 1972 to 2007.

They were followed for several decades (10 to 45 years) for dementia diagnoses.

The study subjects were between 25 and 75 years of age.

“In the analyses, we considered deaths with causes other than dementia, something only a handful of dementia researchers have previously done. Those who die younger never have the time to develop dementia, which usually occurs only in older age. We used statistical models that take mortality into account as a competing risk of death,” said Sonja Sulkava, principal investigator for the study.

“As the population ages, memory disorders are becoming more common. Naturally, this makes understanding their risk factors important. From the perspective of psychiatry, it’s particularly interesting that, through careful modelling, we established a connection between symptoms associated with mental distress and an organic brain disease,” said Professor Tiina Paunio of the University of Helsinki.