Can untreated depression lead to dementia? Research shows a strong link, where untreated depression can speed up memory decline and raise the risk of dementia, though it does not directly cause it in every case.
Depression often brings memory problems, especially in older adults. Studies call depression the main reason for memory loss in this group. A long-term study from 2024 followed people for 16 years and found that depression symptoms came before memory issues, with severe cases leading to faster decline over time[1]. This memory loss from depression is known as pseudodementia. It looks like dementia at first, with forgetfulness and poor focus on tests. But people with pseudodementia usually know their memory is failing and feel upset about it. They struggle due to low motivation or concentration, not true brain damage. The good news is that treating the depression often fixes these memory problems. Cognitive skills like attention and recall improve as depression fades[1].
What happens when depression goes untreated? It can do real harm to the brain. Chronic depression raises stress hormones like cortisol, sparks inflammation, and hurts the hippocampus, the part of the brain that handles memory[2]. A large Swedish study of over 1.3 million adults found that those with a history of depression or chronic stress were twice as likely to get mild cognitive impairment or Alzheimer’s disease. The risk jumped to four times higher if both were present[2]. Untreated depression may not just cause short-term fog. It could push the brain toward lasting changes that look like early dementia[1].
Experts from the Lancet Commission note that up to 45 percent of dementia cases worldwide tie to changeable factors, including depression[2]. Treating depression early helps. Antidepressants and talk therapies like CBT boost neuroplasticity, growing new brain cells and strengthening connections[1]. Simple steps like exercise, mindfulness, and good sleep also lower the risk by cutting stress and inflammation[2].
Depression and dementia often show up together. Up to 40 percent of people with dementia have major depressive symptoms[4]. In Alzheimer’s patients, depression appears in about one-third to one-half of cases[3]. But the key question is the other way around: does skipping treatment for depression invite dementia? The evidence points to yes, through faster cognitive drop and brain damage over time[1][2].
Sources:
https://www.abhasa.in/articles/depression-and-memory-loss/
https://beingpatient.com/how-to-lower-dementia-risk/
https://www.consultant360.com/articles/behavioral-and-psychological-symptoms-dementia-part-i-epidemiology-neurobiology
https://www.thebrf.org/understanding-depression-in-dementia/
