Everyone feels down sometimes, and children and teenagers are no exception. Failing an exam, falling out with a friend, being misunderstood, or losing someone important can all make a person sad, disappointed, or temporarily unwilling to talk.
But if low mood lasts a long time, things you used to enjoy stop being interesting, and sleep, study and relationships are affected, it deserves serious attention.
This article explains: how feeling down differs from depression, what depression can look like in children and teenagers, and what parents can do.
1. What is depression?
In everyday life, “depression” sometimes just describes a low mood or a lack of energy. In mental health, however, depression is a health condition that requires professional assessment.
The World Health Organization (WHO) points out that depression is different from ordinary mood swings: people with depression feel persistently low over a long period, or lose interest and pleasure in activities they used to enjoy, and it may affect family life, social life and study in many ways.
Depression doesn’t only happen to adults — children and teenagers can be affected too.
Feeling down doesn’t necessarily mean depression, and depression is more than just feeling down.
Reference: 1, 2, 6
2. What is the difference between feeling down and depression?
The feelings can be very similar, so you cannot judge whether someone has depression from a single episode of sadness or crying.
| Ordinary low mood | Signs that may need attention | |
|---|---|---|
| Cause | Usually related to something specific, e.g. failing an exam or arguing with a friend | May be related to stress or loss, or there may be no obvious cause |
| Duration | Gradually improves with time, a change of environment, or support | Low or irritable mood persists, or keeps coming back |
| Interest and pleasure | Even though sad, can still get some enjoyment from favourite things | Clear loss of interest in things once enjoyed, and no longer feels pleasure |
| Thinking | Temporarily disappointed, but can usually still see other possibilities | Persistent hopelessness, self-blame, feeling worthless |
| Physical state | May be briefly tired; sleep or appetite affected | Sleep, appetite and energy persistently or clearly changed |
| Daily life | Usually gradually returns to study and social life | Study, school attendance, family relationships, friendships or self-care clearly affected |
This table is only to help understanding, and cannot be used for diagnosis. The two are not all-or-nothing either: people without depression may still need support, and people with depression also have happy moments.
How long does it have to last to count as depression?
Doctors judge by the combination of symptoms, their severity, how often they occur, and the impact on life. Duration is only one important reference point.
According to the National Institute of Mental Health (NIMH) and WHO, a diagnosis of major depression usually requires: low mood, or loss of interest and pleasure, present most of the time and nearly every day, lasting at least two weeks.
But this does not mean:
- being sad for more than two weeks is definitely depression;
- being sad for less than two weeks means no help is needed;
- all the common symptoms must be present before paying attention.
Two weeks is a reference for diagnosis, not a deadline parents must wait for. If a child’s emotional changes are intense, daily life is clearly affected, or there are thoughts of self-harm or suicide, seek help immediately — there is no need to wait two weeks.
Reference: 1, 2
3. What does depression look like in children and teenagers?
Children can’t always put their feelings accurately into words. Some will say “I’m very sad”; some only say “I’m tired” or “I don’t want to do anything”; and some say nothing at all.
So besides listening to what a child says, pay more attention to whether there are persistent changes compared with how they usually are.
1. Persistently low mood, or becoming easily irritated
- Often feeling sad, empty or helpless;
- More irritable, angry or tearful than usual;
- Feeling that things will never get better;
- Feeling worthless, or intense self-blame over small things.
Depression in children and teenagers does not always show as obvious sadness — it can also be persistent irritability, restlessness or mood swings.
2. Losing interest in things once enjoyed
- Once loved sports, drawing, reading or games; now nothing feels interesting;
- No longer willing to see friends, or unwilling to join extracurricular activities;
- Even things once looked forward to feel like too much effort.
The key is not that a child occasionally wants to be alone, but that interest and participation show persistent, clear changes.
3. Changes in sleep, appetite and energy
- Harder to fall asleep than usual, or sleeping much more;
- Appetite clearly increased or reduced;
- Often tired, still lacking energy after rest;
- Movements clearly slowed, or restless and unable to sit still;
- Often complains of headaches or stomachaches with no clear physical cause.
4. Study and concentration affected
- Hard to concentrate in class; homework feels much harder than before;
- Frequent forgetfulness; grades clearly drop;
- Frequently missing school, or refusing to go.
These changes are sometimes mistaken for laziness, not trying hard, or deliberate uncooperativeness. If the child is also persistently low and has lost interest, it is worth looking further into why.
5. Gradually withdrawing from family and friends
A child may reduce contact with friends, avoid group activities, or often feel that nobody understands them. Some teenagers hide their feelings, appearing fine on the surface while suffering a lot when alone.
So you cannot assume a child is fine just because they still go to school and still talk to people.
6. Talking about death, or self-harm
If a child has said they don’t want to live, wants to hurt themselves, or has already self-harmed, it must be taken seriously. Please refer to the advice in part 6.
The signs above can also be caused by other physical or mental health problems, and need professional assessment. Do not judge on these signs alone.
Reference: 2, 3, 4, 5, 6
4. Why do children develop depression?
There is usually no single cause of depression. Genetic, biological, psychological and environmental factors may all play a part. The following can increase psychological stress or be related to depression:
- Study and growing-up pressure: exams, grades, further education, and uncertainty about the future.
- Relationship difficulties: conflict with friends, being excluded or bullied.
- Family and life changes: family conflict, bereavement, traumatic experiences, or abuse and neglect.
- Other health issues: anxiety, attention or learning difficulties, chronic illness, etc. may occur alongside depression.
- Genetics and individual differences: depression or anxiety in the family or in parents is one risk factor, but it does not mean the child will certainly develop it.
A stressful event does not mean depression will definitely develop; and no obvious stressful event does not mean it won’t. We should not simply blame depression on a child not being strong enough, on poor parenting, or on any single event.
Reference: 5, 6, 7
5. If you suspect your child is depressed, what can parents do?
Parents do not need to work out straight away what the child is going through, or rush to conclusions. Start with observation and communication.
1. Observe changes first; don’t rush to blame
Notice whether the child has recently shown persistent mood changes, loss of interest, sleep problems, study difficulties, or unwillingness to see people. You can ask yourself:
- When did these changes begin?
- How do they differ from how the child usually is?
- Have they already affected school, family life or friendships?
- Has the child said they feel helpless or worthless, or that they don’t want to live?
Observation is to understand the situation more accurately — not to make a diagnosis at home.
2. Listen first, then find a way together
Give the child space to express themselves; don’t force them to explain everything right away. You could start like this:
“I’ve noticed you seem more tired lately, and you don’t really want to do things you used to enjoy. I’m a bit worried about you. Has something been upsetting you recently?”
“You don’t have to explain everything now. If you want to talk, I’m here to listen.”
After the child opens up, try not to interrupt or criticise, and don’t rush to give a long list of advice. You can respond first:
“It sounds like this has really been hard for you.”
“Thank you for telling me.”
“We can figure it out together — you don’t have to carry it alone.”
This does not mean parents must agree with everything the child thinks; it means letting them know first that their feelings will be taken seriously.
Try to avoid these reactions, because the child may feel misunderstood and become even less willing to open up: “Why would you be sad?” “You’re just overthinking.” “Others have it harder than you.” “Just cheer up.” “You’re just not trying hard enough.”
Reference: 6, 7
6. When should you seek help? Can depression be treated?
When to seek a professional assessment
If a child shows any of the following, contact a family doctor, clinical psychologist, psychiatrist, or another qualified child and adolescent mental health professional as soon as possible:
- Long-term low mood, irritability, or clear loss of interest;
- Study, school attendance, sleep or relationships clearly affected;
- Persistent feeling of worthlessness, or a belief that the future will not improve;
- Self-harm, or saying they don’t want to live.
Professionals will look at the child’s symptoms, stage of development, family and school environment, and rule out other physical problems that could cause similar signs, before deciding on suitable support or treatment.
If the child is unwilling to talk to parents directly, you can also contact a teacher they trust, a school social worker, or another adult, and ask them to help.
Depression can be treated
Yes. Treatment depends on the child’s age, the severity of symptoms and professional assessment. It may include:
- Psychological therapy: cognitive behavioural therapy (CBT) helps children recognise thought and behaviour patterns related to their emotions and learn more effective coping strategies; interpersonal therapy (IPT) focuses on improving relationships. Both have substantial research support.
- Support from family and school: with professional guidance, parents can help the child keep regular routines and gradually resume appropriate daily activities, and can communicate with the school about the support needed.
- Medication: whether medication is needed must be assessed by a qualified doctor according to the child’s age and condition. WHO notes that antidepressants are not suitable for children and are not the first-choice treatment for adolescents, and must be used with extra caution. In any case, medication must never be bought, started or stopped on your own.
Seeking help doesn’t mean the child has failed, and doesn’t mean the parents have done something wrong. The earlier appropriate support is received, the more the impact on growing up and daily life can be reduced.
Reference: 1, 2, 4, 6, 7
7. Emergencies and where to get help
If a child mentions suicide or self-harm, don’t treat it as “just talk”. Listen seriously, ask calmly and directly whether they are in danger, and seek professional help as soon as possible.
If the child says they might hurt themselves soon, or can no longer keep themselves safe, don’t leave them alone. Stay with them if it is safe and possible, and call 999 immediately or go to the emergency room.
Helplines in Hong Kong
- Emergency danger: 999. If there is immediate danger to life or a serious risk of self-harm, seek help at once.
- “Mental Health Support Hotline” 18111: available all year round, 24 hours a day, providing immediate support, counselling and referrals.
- Hospital Authority Mental Health Direct 2466 7350: 24-hour mental health consultation and referral service.
Reference: 6, 8, 9
To the child going through a low period
You don’t have to prove how much you are suffering in order to deserve help.
Sometimes you are just feeling down and need time to recover; sometimes persistent low mood means you are facing something harder than you imagined. Either way, your feelings deserve to be taken seriously.
If you have been unhappy or lacking energy lately, or feel less and less like your old self, there’s no need to label yourself, and no need to carry it alone. Start by telling someone you trust.
References
The following materials come from international public health organisations, government health agencies and professional child and adolescent psychiatry organisations, and were checked in October 2026.
- World Health Organization (WHO). Depressive disorder (depression). https://www.who.int/news-room/fact-sheets/detail/depression
- National Institute of Mental Health (NIMH). Depression. https://www.nimh.nih.gov/health/publications/depression
- National Institute of Mental Health (NIMH). Teen Depression: More Than Just Moodiness. https://www.nimh.nih.gov/health/publications/teen-depression
- National Institute of Mental Health (NIMH). Child and Adolescent Mental Health. https://www.nimh.nih.gov/health/topics/child-and-adolescent-mental-health
- Centers for Disease Control and Prevention (CDC). Anxiety and Depression in Children. https://www.cdc.gov/children-mental-health/about/about-anxiety-and-depression-in-children.html
- American Academy of Child & Adolescent Psychiatry (AACAP). Depression in Children and Teens (Facts for Families No. 4). https://aacap.org/AACAP/AACAP/Families_and_Youth/Facts_for_Families/FFF-Guide/The-Depressed-Child-004.aspx
- American Academy of Child & Adolescent Psychiatry (AACAP). Depression Resource Center: Frequently Asked Questions. https://www.aacap.org/AACAP/AACAP/Families_and_Youth/Resource_Centers/Depression_Resource_Center/Frequently_Asked_Questions.aspx
- Government of the Hong Kong Special Administrative Region. Government launches 24-hour mental health support hotline “18111” (press release, 27 December 2023). https://www.info.gov.hk/gia/general/202312/27/P2023122700238p.htm
- Hospital Authority (Hong Kong). Mental Health Direct. https://www.ha.org.hk/haho/ho/cc/Mental_Health_Direct_ENG.html
Disclaimer: This article is for public mental health education only, and does not constitute medical advice or diagnosis. If a child or teenager experiences persistent, severe emotional distress, or daily life is clearly affected, please seek assessment and help from a qualified professional.