A recent study published in the Biological Psychiatry journal suggests that treating depression, especially in individuals showing increasing depressive symptoms, can significantly reduce their risk of developing dementia. As such, there are potential benefits of timely depression treatment — not just in alleviating depressive symptoms, but possibly in reducing the risk of dementia as well.
Dementia, a condition characterized by a decline in memory and cognitive abilities, has long been a subject of concern for medical researchers. With age, the risk of both depression and dementia increases. Previous research has tried to understand if there’s a connection between these two conditions. One of the debates has been whether depression is merely an early sign of dementia or if it independently contributes to its onset.
Researchers embarked on this study to delve deeper into the intricate relationship between depression and dementia. Their primary interest was to determine how the course of depression affects the risk of dementia and if depression treatments have any impact on this risk.
“Older individuals appear to experience different depression patterns over time,” explained study author Jin-Tai Yu of Fudan University. “Therefore, intra-individual variability in symptoms might confer different risk of dementia as well as heterogeneity in effectiveness of depression treatment in relation to dementia prevention.”
To understand this, the team examined 354,313 participants aged 50 to 70 — all of whom were recruited from a UK Biobank cohort. All of the participants had dementia, and a subgroup of individuals who had depression diagnosed during or prior to dementia onset was identified.
Researchers then categorized the subgroup participants based on their depressive symptoms into different courses: increasing, decreasing, and chronically high or low. Subsequently, they compared the risk of developing dementia between those who received depression treatments (either antidepressants or psychotherapy) and those who did not.
The researchers found that participants with untreated depression were found to be 30% more likely to develop dementia compared to those who underwent treatment. The protective effect of treatment was most prominent in those with an increasing course of depressive symptoms.
In other words, when breaking down the treatment types, both antidepressants and psychotherapy showed protective effects against dementia, especially for those on the increasing course.
“Once again, the course of ineffectively treated depression carries significant medical risk,” said Biological Psychiatry editor John Krystal in a news release. He notes that, “in this case, symptomatic depression increases dementia risk by 51%, whereas treatment was associated with a significant reduction in this risk.”
“This indicates that timely treatment of depression is needed among those with late-life depression,” added study author Wei Cheng. “Providing depression treatment for those with late-life depression might not only remit affective symptoms but also postpone the onset of dementia.”
“The new findings shed some light on previous work as well,” said Professor Cheng. “The differences of effectiveness across depression courses might explain the discrepancy between previous studies.”
Alongside the valuable insights this study may offer, it is important to note that since the participants were aged strictly between 50 to 70, the results might not apply to older individuals or other age groups. The study’s design also couldn’t firmly establish if depression is a precursor to dementia or an independent risk factor. Furthermore, as the data was drawn from a specific cohort, there might be unmeasured alternative factors influencing the relationship between depression treatment and dementia risk.
The study, “Depression, Depression Treatments, and Risk of Incident Dementia: A Prospective Cohort Study of 354,313 Participants”, was authored by 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, and Jin-Tai Yu.