Sadness with Consequences: Will Depression help treat dementia
In recent years, depression in the elderly has ceased to be perceived solely as a reaction to loneliness, chronic illnesses, or a "difficult age." More and more studies show that it sometimes appears long before a person is diagnosed with Parkinson's disease or dementia. And in a few years. This forces doctors to look at depression in late life in a new way: perhaps in some cases it is not a consequence, but one of the first signals of the neurodegenerative process.
Why can depression be an early sign of dementia?
A recent major study published in the journal General Psychiatry is just about that. The researchers analyzed data from Denmark's national medical registries and compared the frequency of depressive episodes in almost 18,000 people who were later diagnosed with Parkinson's disease or dementia with Lewy bodies with those in control groups of patients of the same age and gender with other chronic diseases.
The result was significant. In people who were subsequently diagnosed with neurodegenerative disease, depression occurred significantly more often — and several years before the official confirmation of the disease. The frequency of depressive episodes gradually increased and peaked about three years before diagnosis. After that, the level of depression remained higher than in people with rheumatoid arthritis, chronic kidney disease or osteoporosis — that is, other severe age-related diseases.
The association between dementia and Lewy bodies was particularly pronounced, which is the second most common cause of dementia in people over 75 years of age after Alzheimer's disease. The researchers suggest that this is due to an earlier lesion of the brain structures responsible for emotions and behavior.
The main conclusion cautiously reached by the authors is that depression in old age can sometimes be not just an emotional problem, but an early sign of neurodegenerative changes.
Why is this important?
The data obtained confirms the trend that has already emerged in medicine. Today, doctors are increasingly looking at depression not as an isolated mood disorder, but as a possible signal of deeper changes in the body, including in the brain. This is especially true for people of mature and elderly age.
If, as the authors of the study believe, depression can be a very early sign of developing dementia or Parkinson's disease, this will allow doctors to start therapy in advance, significantly slowing the development of the disease.
Therefore, the clinical approach is changing today: many general practitioners and neurologists already consider depression not only as a mental disorder, but also as a possible early signal of neurodegenerative processes. At this stage, specialists have a "window of opportunity" — a time when it is still possible to slow down the development of pathological changes.
If we consider depression as a possible early marker, for example, of Parkinson's disease, several years before the appearance of tremor and stiffness of movements, then the patient receives a period of time "won" from the disease, which should become a time of active prevention. An integrated approach plays an important role, doctors say: drug therapy, physical activity, cognitive training and psychotherapy.
According to Marina Anikina, a neurologist, dementiologist, Candidate of medical Sciences, at the first signs of such processes it is important to undergo a detailed neuropsychological examination. These are special tests that evaluate different brain functions: how easy it is for a person to choose words and formulate thoughts, hold attention, memorize new information, navigate in space and plan a sequence of actions.
According to the expert, the selection of therapy plays an important role. Some antidepressants increase levels of brain—derived neurotrophic factor (BDNF), a protein that supports the viability of neurons and their ability to form new connections. Experimental studies also discuss their effect on the processes of cleansing the brain of pathological proteins, including alpha-synuclein, associated with Parkinson's disease.
By the way, interest in this effect of medications increased during the COVID-19 pandemic, when antidepressants demonstrated anti-inflammatory and neuroprotective properties in prolonged post-viral depressive states.
Can treatment of depression change the prognosis?
There is no direct answer yet. Currently, most of the data is observational: they show a link, but do not prove that depression causes dementia. It can be an early symptom of it, an important risk factor, or a process that develops in parallel.
Nevertheless, doctors agree on one thing: it is dangerous to ignore depression in old age. Especially if it occurs for the first time.
— Depression is a biological process that is accompanied by inflammatory reactions and adverse changes in the functioning of nerve cells. If the episode lasts more than a month, permanent changes may form — neuroplasticity decreases, that is, the brain's ability to adapt and recover. The structures responsible for memory, motivation, and behavior control are particularly vulnerable," the expert explains.
The relationship between depression and dementia does not mean that every depressive episode in old age is a harbinger of a serious diagnosis, emphasizes the neurologist of the highest category, head of the ANO "Healthy Dialogue" Ali Ismailov.
But there are situations that require increased attention, primarily the late onset of depression.
— If an elderly person experiences depression for the first time, especially in combination with sleep disorders, severe fatigue, slow thinking or episodes of confusion, this is not a reason to panic, but a serious reason to consult a doctor. It is important not to attribute the changes to "age," but to assess overall health, memory, attention, and sleep quality," advises Ismailov.
Why is depression difficult to distinguish from dementia?
The problem is that depression itself can disguise itself as cognitive impairment. A person thinks slower, gets tired faster, concentrates worse and remembers new information. These symptoms are called secondary cognitive impairments — they are not related to the death of neurons, but to the influence of an emotional state. In the treatment of depression, such changes are often reversible.
"Therefore, with the late onset of depression, it is important not to limit ourselves to talking about mood," explains Marina Anikina, a neurologist and dementiologist. — We need a detailed neuropsychological assessment: memory, attention, speech, the ability to plan actions. It helps us understand what we're dealing with."
Additional information is provided by neuroimaging methods. On an MRI scan, doctors pay attention to the hippocampus, a brain structure associated with memory formation, as well as the frontal lobes and vascular changes.
"If depression is combined with a decrease in the volume of the hippocampus or signs of atrophy in the frontal lobes, we consider the situation broader than just an affective disorder," says Anikina.
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