Psychologist explained the effects of depression on the brain and body
Depression is one of the leading causes of disability in the world: according to WHO, more than 280 million people suffer from the disorder. The disease changes not only the mood, but it rebuilds the work of the brain, body and immune system, and long before a person seeks help. About how depression changes neural networks, why antidepressants do not destroy personality and how not to harm loved ones in a crisis — in the material of Izvestia.
How depression disguises itself as fatigue
What is depression?
Depression is one of the leading causes of disability worldwide. According to the World Health Organization (WHO), more than 280 million people suffer from the disorder.
Depression rarely starts suddenly. In most cases, the disorder is preceded by a prodromal phase, a period that lasts weeks and months and looks like normal fatigue or stress. At this stage, there are mild sleep disturbances, periodic irritability, decreased energy, increasing difficulty concentrating, and an indefinite feeling of anxiety or inner restlessness. It is during this period that most people do not consult a doctor — the symptoms seem too vague and familiar.
"Depression can go unnoticed for a very long time, sometimes for months or even years. Especially if a person is used to living in a state of constant tension, fatigue, or emotional suppression. Depression is a disease that affects both the psyche and the functioning of the body as a whole," Maria Todorova, a child and family psychologist and neuropsychologist, explained to Izvestia.
Risk factors include chronic stress and emotional burnout, severe life events such as bereavement, divorce, job loss, early psychological trauma, chronic physical illnesses, and circadian rhythm disorders. Increased sensitivity and a tendency to self-criticism create additional vulnerability.
The first mental signals are a persistent decrease in interest in habitual activities, loss of the ability to enjoy, and a growing sense of guilt and hopelessness. They are joined very early by physical symptoms: changes in appetite and weight, sleep disorders, and a feeling of constant fatigue for no apparent reason. It is sleep changes — early awakenings, not refreshing sleep, nighttime awakenings with anxiety — that often turn out to be the very first visible signs of incipient depression, but they can easily be attributed to stress.
Physical symptoms of depression
Depression is considered to be a mood disorder, but it also changes the body — even before a person realizes that he is ill. Even without treatment, the overall activity level decreases, chronic fatigue, muscle tension, headaches, gastrointestinal complaints, and unstable weight appear. These changes are not related to the effect of drugs, but to an imbalance of stress hormones, a violation of biological rhythms and a restructuring of the autonomic nervous system.
"Sleep disorders often occur — either insomnia or constant drowsiness. Appetite changes, motivation decreases, and there is a sense of meaninglessness," Todorova said.
Behavioral markers by which a specialist may suspect a chronic course of the disease long before neuroimaging include persistent social isolation, abandonment of hobbies, a marked decrease in initiative, and "getting stuck" in negative thoughts about oneself and the future.
Biologically, depression disrupts the functioning of neurotransmitter systems — serotonin, norepinephrine, dopamine — increases the activity of stress axes, is associated with atrophy of the hippocampus and prefrontal cortex and a decrease in the number of synaptic connections. This affects the work of internal organs: the rhythms of hormone release, heart rate, body temperature, and immune regulation change — which, in turn, increases the risk of somatic diseases and worsens the course of existing ones.
Depression often "comes through the body": chronic pain, fatigue, sleep and appetite disorders are so pronounced that patients first turn to therapists and neurologists rather than to a psychiatrist. The psychosomatic aspect here is two—sided: a mental state worsens physical health, exacerbates existing diseases — from diabetes to immune disorders - and can provoke new ones; at the same time, chronic inflammation and pain themselves increase the risk of depression.
Inside the depressed brain
Modern neuroscience describes depression not as a breakdown of a single "point" in the brain, but as a malfunction of large functional networks. In people with major depressive disorder, the organization of neural connections is disrupted: large networks connecting different parts of the brain become less well-ordered, while subnets associated with self-referential reflections turn out to be overly active.
The interaction between the central executive network (CEN), which provides voluntary attention and cognitive control, and the passive brain mode network (DMN), which is associated with self—reflection and internal dialogue, plays a key role. A study published in Scientific Reports in 2026 showed that it is the duration of depression that determines how much the severity of symptoms affects the connection between these networks.
The authors analyzed functional MRI scans of 46 patients with major depressive disorder. In those who had been ill relatively recently, as the symptoms increased, the functional relationship between the CEN and the DMN zones — primarily the areas around the parietal lobe on the inner surface of the cerebral hemispheres (preclinium) — decreased. In patients with chronic depression lasting more than two years, the opposite pattern was observed: the more severe the symptoms, the stronger this relationship.
Such a pattern may underlie the fact that a person gets "stuck" in negative rumination and it becomes increasingly difficult for him to switch to external tasks and stimuli. Structurally, the severity of depression in the same study was associated with changes in gray matter volume in the anterior cingulate cortex and the right dorsolateral prefrontal cortex, regions traditionally involved in mood regulation. Important: all participants did not take antidepressants, so the identified changes reflect the effect of the disease itself, not the therapy.
"With chronic depression, a person may no longer remember what he was like before this condition, and perceive his condition as normal," Todorova emphasized.
Cognitive impairments—problems with attention, memory, and information processing speed—are considered one of the key components of an episode. Some of them are reversible with effective treatment, but the data from the 2023 review indicate a "scarring" effect of multiple episodes: psychomotor and mnestic deficits increase with each relapse and do not fully recover even in remission.
The price of procrastination: What happens if depression is not treated?
Neuroimaging data confirms what doctors have long warned about: the longer depression remains untreated, the deeper the changes in the brain. The duration of the episode, as shown by the study on the relationship between CEN and DMN, directly enhances the severity of these changes.
"If depression is not treated, it tends to become entrenched. After a few years, chronic depression begins to affect almost all areas: the risk of anxiety disorders, addictions, psychosomatic diseases, and cardiovascular problems increases," the psychologist warned.
Without therapy, the risk of chronicity increases with deeper changes in brain networks, persistent cognitive dysfunction, increased somatic diseases, and increased suicidal risk. Modern reviews describe depression and inflammation as a "double trouble": a significant proportion of patients show dysregulation of both innate and acquired immunity — increased levels of pro-inflammatory cytokines, which worsen the prognosis and response to therapy. Inflammation can be both a risk factor — a consequence of early trauma, chronic stress — and a consequence of already developed depression.
Antidepressants: what do they actually do to the brain?
One of the main barriers to treatment is the fear of antidepressants. Many patients are afraid of "getting hooked," "losing themselves," or "becoming a different person." Neuroscience provides specific answers to these fears.
"Antidepressants often cause fear because people hear the phrase "affect the brain." But it's important to understand that with depression, the brain already works differently. The balance of neurotransmitters is changing, and the regulation of emotions, sleep, anxiety, and concentration is disrupted. Antidepressants do not break a person's personality and do not make a person different. Their task is to help the brain return to more stable work," Todorova explained.
The classic idea of "correcting chemical imbalances" is now considered a simplification: antidepressants act not only through changes in serotonin or norepinephrine levels, but also trigger neuroplastic processes. Chronic drug use is associated with a decrease in hippocampal atrophy, increased neurogenesis, increased levels of neurotrophic factors, and the restructuring of synaptic connections, which makes mood networks more stable.
Functionally, antidepressants alter activity patterns in the prefrontal cortex and limbic structures: A number of studies show a decrease in hyperactivity in certain prefrontal areas and normalization of reactions to emotional stimuli, as well as an effect on neurovascular connectivity and energy metabolism of the brain. According to UCLA Health, this is clinically manifested not by an instantaneous rise in mood, but by a gradual change in perception: negative bias decreases, a person interprets signals from the outside world differently, and a "gap" appears for other reactions.
"Pull yourself together" doesn't help: how to talk to a depressed person
Loved ones often intuitively do things that only increase suffering in depression: they minimize their condition ("get together", "everyone has problems"), appeal to their will, compare them with "more unhappy people", criticize them for "laziness" and social passivity. Such words reinforce the belief that "something is fundamentally wrong with me" and increase the risk of going into isolation.
"A lot depends on the reaction of loved ones. Depression is not cured by willpower and the words of loved ones "calm down", "don't cry", etc. Such phrases increase feelings of guilt and loneliness. Support does not begin with advice, but with the recognition that it is really hard for a person. Sustainable recovery is always associated not only with medical support, but also with a sense of security, acceptance, and emotional support. The human nervous system recovers better where there is contact, support and lack of constant pressure," concluded Todorova.
A more constructive strategy is to recognize the reality of the disease, not try to "fix" a person with advice, gently but persistently support contacting specialists and help with everyday life, relieving unbearable workloads. Psychotherapists and patients themselves name several triggers that should be consistently avoided: devaluation ("you're not that bad," "it's just laziness"), threats and ultimatums ("either you pull yourself together, or..."), coercion to "positive thinking" and comparison with "normal" ones people, as well as discussing suicidal thoughts in a judgmental tone or as manifestations of "manipulation."
Depression support is about creating a stable, predictable environment and helping a person get to treatment, not inspiring speeches. A calm presence, a willingness to listen without evaluation, a rejection of pressure and demands for immediate success, and a careful attitude to topics that enhance self—criticism - work, productivity, and appearance - are important.
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