TL;DR: Feeling bored for a few hours to a few days and then getting over it is normal and everyone experiences it. But when mood sinks, interest is lost, and fatigue lasts for two weeks or more and starts affecting sleep, work, study, or relationships, that is the time threshold that professionals consider a sign to seek medical care. Depression is a diagnosable and treatable mental health disorder, not weakness or a matter of fate. According to the WHO (fact sheet updated 11/09/2026), in 2023 an estimated 5.2% of adults worldwide had depression, about 322 million people, and women were affected about 1.5 times more than men. If you or a loved one has thoughts of suicide or is at risk of self-harm, call emergency services at 115 or go to the nearest medical facility immediately.
Prolonged sadness: folk belief often blames fate, but being sad for more than two weeks is a sign to see a doctor, and how to recognise it yourself
What is prolonged sadness and how does it differ from everyday sadness?
Prolonged sadness is a state in which mood stays low for many consecutive days and does not fade on its own when circumstances change. The fundamental difference from everyday sadness lies in three factors: duration, how far it spreads, and how much it affects daily functioning.
In life, everyone goes through periods of sadness, stress or disappointment. These feelings usually last only a short time and gradually improve as circumstances change. Even optimistic people have moments when their mood sinks. Psychologists call this phenomenon "low spirits", and young people's slang calls it "down mood" or "losing your mood". It often comes after pent-up pressure from study or work, conflict in romantic relationships, friendships or family, or simply an imbalance in daily habits such as staying up late repeatedly, eating irregularly, or working too much.
Depression is different. It is a condition in which low mood lasts at least two weeks, accompanied by loss of interest in activities that were once enjoyed, reduced energy, and many changes in emotion, thinking and physical state. Depression is a mental health disorder that can be diagnosed and treated, not a weakness.
According to the World Health Organization (WHO), in its Depressive disorder (depression) fact sheet updated on 11 September 2026, an estimated 5.2% of adults worldwide had depression in 2023, including 4.1% of men and 6.2% of women, equivalent to about 322 million people. Depression in women is about 1.5 times as common as in men. This is an illness that needs to be diagnosed and treated like other chronic diseases, not a sign of weakness or lack of willpower.
Why does folk belief often blame fate?
Explaining things through fate comes from people's need for a story to make sense of unexplained pain. When mood sinks without a clear reason, blaming it on "a bad star this year" helps people feel less guilty and gives them a sense of control. But this way of explaining things has a price: it delays seeking medical help, while time is the factor that decides the prognosis of depression.
One thing needs to be said clearly: this article does not deny the reader's spiritual experience, it only seeks to separate two planes. Personal belief is a private matter; but when symptoms have lasted beyond the two-week threshold and affect daily functioning, that is a health issue that needs professional examination.
How long does sadness have to last to count as a sign of illness?
Two weeks is the time threshold that professionals use as the standard for diagnosing major depressive disorder. Specifically, if a state of low spirits lasts two weeks or more, accompanied by not wanting to interact with people around you and a harmful effect on the ability to study or work, the person may be at risk of depression. This threshold was stated by Dr Đoàn Sơn Tùng, at the Central Mental Hospital I, in an article in Suc khoe & Doi song newspaper.
It must be stressed that two weeks is not an absolute number used for self-diagnosis. It is a milestone that tells you when to book an appointment with a doctor or psychologist. If the phenomenon lasts only a few hours or a few days, there is not yet reason to worry too much, because that may only be mental unease or a temporary mood disorder.
Comparison table: everyday sadness and sadness that needs a doctor
| Criterion | Everyday sadness (low spirits) | Sadness that needs a doctor (risk of depression) |
|---|---|---|
| Duration | A few hours to a few days, passes on its own | Two weeks or more, does not pass on its own |
| Cause | Usually a clear trigger: exam pressure, conflict, lack of sleep | May have no clear cause, or the cause has passed and the sadness remains |
| Interest | Still want to do things you enjoy | Loss of interest even in activities once enjoyed |
| Energy | Tired but recover after rest | Persistent fatigue, low energy almost every day |
| Sleep and eating | May be mildly disrupted, then settle | Insomnia or sleeping too much, irregular eating, weight change |
| Thinking | Can still concentrate when needed | Hard to concentrate, reduced memory, slowed down or restless |
| View of oneself | Feel it will pass | Constantly self-blaming, feeling useless |
| Effect on functioning | Work and study can still keep going | Clear effect on work, study and relationships |
| Thoughts of self-harm | None | May appear, especially when severe |
Which signs of depression do many people overlook?
The three typical signs of depression are a prolonged state of sadness or emptiness, loss of interest in life, and always feeling tired and low on energy. But "typical" does not mean "easy to see". Many people have depression without realising it at all, because their signs do not match the usual image of a "gloomy" person.
Besides the three main signs, patients may also have insomnia or sleep too much, irregular eating leading to weight change, difficulty concentrating, reduced memory, slowing down or restlessness, and constantly blaming themselves and feeling useless. In severe cases, thoughts of self-harm or suicide may appear.
In particular, in the early stage, depression is often very hard to detect. Patients often show only general symptoms such as dizziness, headache and insomnia. These patients often go to various specialties without finding a specific cause, because they do not think the root lies in mental health.
Symptoms differ by sex and age
Depression symptoms are not the same in everyone. Older people often complain of body aches, fatigue or loss of appetite rather than talking about emotions. Men may become easily irritable, abuse alcohol, or throw themselves into work, while adolescents often withdraw, see their school results drop, or change their behaviour. So not everyone with depression shows obvious sadness.
This is why recognising the illness based on the feeling of "am I sad?" is not enough. You need to look at changes in behaviour compared with your earlier self: sleeping less or more, eating less or more, giving up old pleasures, avoiding gatherings, work results falling even though you still try.
Why is depression easily confused with other illnesses?
In the diagnosis and assessment of depressive disorders, it is very easy to mistake them for other disorders such as anxiety disorders, schizophrenia or bipolar disorder. Relying only on diagnostic criteria at the time of the examination is not enough. Usually a doctor needs at least two to three appointments before correctly assessing the patient's condition.
One example shared from clinical practice: a patient, after examinations, was assessed at the third appointment as having a depressive disorder. But at the end of the session, the patient shared a past experience, a time when he was very cheerful, full of life, comfortable going out without fear as he does now. The doctor realised there was a need to monitor and reassess. Only at the fourth appointment was the accurate result reached: bipolar mood disorder, meaning a person has two mood phases, a depressive phase and a manic phase. The patient came to the doctor while in the depressive phase, and these two phases may be months, even a year, apart.
Why do many people have depression?
Depression usually does not come from a single cause but from a combination of many factors. Biological factors such as genetics or disrupted activity of neurotransmitters in the brain can raise the risk of illness. In addition, people with perfectionist traits, who constantly criticise themselves, or who have been through psychological trauma are also more prone to depression.
Life events such as losing a loved one, a marriage breaking down, work pressure, financial difficulty or prolonged loneliness can all be triggers. Some chronic diseases such as diabetes, cardiovascular disease, chronic pain, thyroid disorders, the postpartum period, or alcohol and stimulant abuse are also linked to the risk of depression. Depression can also appear because of diseases or injuries that directly affect the brain, because of physical illnesses such as cancer, or the after-effects of COVID-19. People who smoke, drink alcohol, or use nerve-damaging stimulants are also more prone to depression.
This shows that even people with stable lives can still become ill if several risk factors appear together. Conversely, some cases are classified as "endogenous", meaning depression of unknown cause, with various hypotheses such as genetics, autoimmune factors, living environment, and hormonal changes.
When should you see a doctor, and how does treatment happen?
If sadness, loss of interest or fatigue lasts two weeks or more and affects work, study, sleep or relationships, the patient should go to a specialist facility for examination. Early treatment not only helps improve symptoms but also reduces the risk of relapse and serious complications, including suicidal behaviour.
Depression is an illness that can be treated effectively if detected early. After examination and assessment of symptoms, the doctor will build a treatment plan suited to each patient. For mild cases, psychotherapy is usually the preferred choice. Methods such as cognitive behavioural therapy (CBT) help patients recognise negative thoughts, change how they see problems, and gradually restore positive activities in life. For patients with moderate and severe levels, the doctor may combine psychotherapy with antidepressants to improve treatment effectiveness. There are also other methods such as electroconvulsive therapy (ECT), along with psychodynamic, family and cognitive behavioural therapies to provide psychological support for the patient.
What to know about antidepressants
Antidepressants usually need two to six weeks to show clear effects. Patients should not stop the medication on their own when symptoms improve, because this can raise the risk of relapse. Antidepressants are not addictive, but stopping suddenly can cause discontinuation syndrome with symptoms such as dizziness, insomnia, anxiety or nausea. Therefore, reducing the dose or stopping the medication needs to be done under the doctor's guidance.
Recovery usually takes time and persistence, so patients should not rush or change the treatment plan on their own. One point worth noting: patients who are just beginning with mild depression can often be treated relatively easily with medication and psychotherapy, but if the illness is allowed to progress to moderate and severe depression, it is much harder to treat.
The biggest barrier is the illness itself
Simply having the patient go to a doctor or psychologist is already half the battle won. However, the endogenous illness itself makes patients not want to contact or share with anyone, and withdraw, so getting them to seek out a professional, a relative or a friend is very hard.
What should patients and their loved ones do?
Besides treatment, people with depression should maintain a healthy lifestyle by sleeping and resting regularly, eating adequately, exercising appropriately, and staying in contact with family and friends to avoid feeling isolated. At the same time, they should limit alcohol and stimulants and avoid making important decisions while symptoms are not yet stable.
When in a state of low spirits, trying to keep working or studying usually does not bring high effectiveness, because the brain's ability to concentrate, pay attention and absorb information at that time is very poor. Resting does not mean giving up work. Sometimes simply letting the body relax for a few hours with favourite activities also helps regenerate energy and shed some sad thoughts and anxious feelings.
Family and friends play an important role in the recovery process. Instead of advising the patient to "think positively" or "stop being sad", listen, encourage, and actively support with concrete actions such as taking the patient to an appointment or accompanying them in daily life. If you or a loved one has thoughts of suicide or is at risk of self-harm, call emergency services on 115 or go to the nearest medical facility immediately.
Recognising it yourself: a few questions for self-reflection
There are simple questions that help you assess yourself without waiting until you break down. Over the past two weeks, have you felt you have lost interest in things you once enjoyed? Have you felt tired even when you have not done anything strenuous? Have your sleep and eating changed noticeably? Do you often blame yourself and feel useless? And most importantly: have these things affected your work, study or relationships yet?
If many answers are "yes", treat that as a signal to book an appointment with a doctor or psychologist, not as a reason to conclude on your own that you have an illness. Diagnosis still belongs to a professional, and usually needs more than one appointment.
A note on the limits of this article
This article gathers information from health news sources and interviewed experts, to help readers recognise the time threshold at which they should see a doctor. It does not replace a doctor's diagnosis and treatment prescription. Statistical figures on illness rates may differ between sources and between countries.
How long should prolonged sadness last before seeing a doctor?
Two weeks is the time milestone that professionals use to distinguish everyday sadness from a condition that needs examination. If low mood, loss of interest or fatigue lasts two weeks or more and begins to affect sleep, work, study or relationships, you should book an appointment with a doctor or psychologist. If it lasts only a few hours to a few days and then passes on its own, that is usually not yet a worrying sign.
Remember that two weeks is a milestone for seeing a doctor, not for self-diagnosis. Determining whether you have depression still belongs to a professional, and usually needs more than one appointment, because depression is easily confused with other disorders such as anxiety or bipolar disorder.
Is prolonged sadness caused by fate?
There is no medical basis for saying that fate causes depression, but this article does not deny the reader's personal beliefs. Blaming unexplained sadness on "a bad star this year" can help people feel less guilty and feel a little control, but the price is that it delays seeking medical help, while time is the factor that decides the prognosis of depression.
Spiritual belief is each person's private matter. What is worth considering is only this: when symptoms have lasted beyond the two-week threshold and affect daily functioning, that is a health issue that needs professional examination, alongside whatever belief you hold.
Is depression a weakness?
No. Depression is a mental health disorder that can be diagnosed and treated, not a weakness or a lack of willpower. According to the World Health Organization (WHO) in its Depressive disorder (depression) fact sheet updated on 11 September 2026, an estimated 5.2% of adults worldwide had depression in 2023, equivalent to about 322 million people, and depression in women is about 1.5 times as common as in men.
Depression usually does not come from a single cause but from a combination of many factors: genetics, disrupted activity of neurotransmitters, perfectionist personality, psychological trauma, life events, chronic disease, or alcohol and stimulant abuse. So having the illness is not the patient's fault, and seeing a doctor early is a proactive act, not a sign of weakness.
