Timely intervention for depression may reduce the risk of dementia in the future

Depression has long been linked to an increased risk of dementia, and now a new study provides evidence that prompt treatment of depression can reduce the risk of
dementia in specific populations.

More than 55 million people worldwide suffer from dementia, a neurocognitive disorder
that primarily affects older adults.
There is currently no effective treatment for dementia, but identifying ways to help reduce or prevent dementia will help reduce the burden of
the disease.

The study, led by Jin-Tai Yu, MD, of Huashan Hospital, Shanghai Medical College, Fudan University, and Dr.
Wei Cheng, of the Institute of Brain-Inspired Intelligence Science and Technology of Fudan University in Shanghai, China, was published in Biological Psychiatry and published by Elsevier
.

Professor Yu and Professor Cheng used data collected by the UK Biobank, a population-based cohort
of more than 500,000 participants.
The current study included more than 350,000 participants, 46,280 of whom suffered from depression
.
Over the course of the study, 725 people with depression developed dementia
.

Previous studies examining whether depression therapies such as medication and psychotherapy could reduce the risk of dementia have had mixed results, an issue that has not been addressed
.
"Over time, older people seem to experience different patterns of depression," Professor Yu said
.
"Therefore, variability in symptoms within individuals may entail different dementia risks, as well as heterogeneity in the effectiveness of depression treatments associated with dementia prevention
.
"

To address this heterogeneity, the researchers divided participants into four stages of depression: an increase phase, with a steady increase in initial mild symptoms; the course of mitigation, which begins with moderate or highly severe symptoms, but then gradually decreases; Chronic high course with persistent severe depressive symptoms; There is also chronic depression, where mild or moderate depressive symptoms persist.

As expected, the study found that depression increased the risk of dementia — a whopping 51 percent
compared to non-depressed participants.
However, the degree of risk depends on the course of depression; Those who are persistently depressed, chronically depressed, or chronically depressed are more likely to develop dementia, and those with a reduced course of disease are no more at greater risk
than those without depression.

What the researchers wanted most was whether receiving treatment for depression reduced the risk of
dementia.
Overall, people with depression who received treatment had about a 30%
lower risk of dementia than those who did not receive treatment.
When the researchers distinguished participants by course of depression, they found that those with an increasing duration of depression and a lower long-term duration had a lower risk of developing dementia after treatment, but those with a higher long-term course did not benefit
from treatment in terms of dementia risk.

John Krystal, MD, editor of biological psychiatry, said: "Once again, the process of depression that is ineffective in treatment poses significant medical risks
.
" "In this case, symptomatic depression increased the risk of dementia by 51 percent, and treatment was associated
with a significant reduction in that risk," he noted.
”

Professor Cheng added: "This shows that patients with advanced depression need timely treatment
.
" "Providing depression treatment to those with older people with depression may not only relieve emotional symptoms, but may also delay the onset
of dementia.
"

Professor Cheng said: "These new findings also provide some clues
to previous research.
" "Differences in effectiveness between different courses of depression may explain differences in
previous studies.
"

Journal Reference:

1. Liu Yang, Yue-Ting Deng, Yue Leng, Ya-Nan Ou, Yu-Zhu Li, Shi-Dong Chen, Xiao-Yu He, Bang-Sheng Wu, Shu-Yi Huang, Ya-Ru Zhang, Kevin Kuo, Wei Feng, Qiang Dong, Jian-Feng Feng, John Suckling, A David Smith, Fei Li, Wei Cheng, Jin-Tai Yu.
   Depression, Depression Treatments, and Risk of Incident Dementia: A Prospective Cohort Study of 354,313 Participants.
   Biological Psychiatry, 2022; DOI: 10.
   1016/j.
   biopsych.
   2022.
   08.
   026