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Blog: Why is my teenager tired?


Have you ever felt your teenager seems always exhausted and less energetic than normal? Here are some signs that your child may be tired or ‘lethargic’.

  • Quieter than usual and/or talking less.
  • Erratic or odd sleeping Patterns.
  • Poor concentration and memory.
  • Getting more irritable with homework and simple tasks.
  • Not as interested as before in hobbies and socializing.
  • Irregular and/or reduced dietary intake.


Causes for Tiredness – Stress, Caffeine, Infections…..

There are many causes for tiredness. Some of the common causes are as below.

  • Infections – Viral infections such as EBV (aka ‘Mono, Glandular Fever or Kissing Disease, Ebstein-Barr Virus) can lead to prolonged tiredness. This starts off with fever, sore throat and swollen neck lymph nodes. Although most people recover after 1 month, a longer period of tiredness can follow. Sometimes this can lead to Chronic Fatigue Syndrome where symptoms persist for more than six months.


  • Poor Nutrition & Anaemia – Girls are more prone to anaemia (low red blood cells) if they have heavy periods. Teenagers with diets lacking in iron and vitamins can lead to poor red blood cell production and tiredness.


  • Thyroid Problems – The thyroid is a gland in the neck which produces hormones which regulate your metabolism. A lack of thyroid hormone or ‘hypothyroidism’ can cause tiredness, weight gain and skin changes.


  • Mood & Stress Problems – The transition period between being a child and becoming an adult is full of stressors – emotionally, physically and socially.  If there are persistent negative thoughts and feelings this can lead to poor sleep patterns, lack of joy in activities and tiredness – a diagnosis of depression may be made.


  • Poor Sleeping Habits – Cell phones, computer games, the internet, homework, going out – there are numerous distractions that can disrupt a good night’s sleep. Does your teenager have a regular sleeping time or has irregular naps throughout the day? Irregular napping have been shown to disrupt the body’s natural cycle, and can leave you more tired than refreshed.


  • Caffeine, Drugs & Alcohol – Teenagers are naturally curious, and may experiment with illegal/legal drugs and alcohol. Caffeine withdrawal can lead to tiredness and disrupted sleeping patterns. Caffeine can be found in high amounts in energy drinks, fizzy drinks and coffee. Certain prescription medications particularly for epilepsy, heart or mood disorders can also lead to tiredness.


  • Diabetes – High or low blood sugars can lead to irritability, mood changes and chronic fatigue.


  • Other Causes – Less common causes include cancers, absence seizures, kidney diseases and brain malformations.

What do I need to do?

If your teenager is suddenly very tired, especially if associated with a headache or a head injury it is best to seek medical advice urgently.

If you have noted your teenager tiredness come on gradually, you should take time to speak to him/her. Ask about how they are feeling, physically and emotionally. Take note of any stressors, whether they are at home, school or even online. Try and approach your teenager’s friends or teachers to see if the problem is consistent inside and outside of school. Explore the sleep pattern of your teenager – are they using their phone till midnight? Are they napping during the day? Think about drug and alcohol use – have you note any medication or alcoholic drinks missing from your home? Have you noticed any unusual smells from your teenager’s room? Are they drinking copious amounts of coffee or energy drinks?

If the cause is unclear then you should seek medical advice from a medical doctor. Your doctor will take a history and do a physical examination to look for clues. Your doctor then may order some investigations (e.g. blood, urine tests, scans) to try and determine a cause. Sometimes further help is required from are made to Neurologists, Psychiatrists and Counsellors if no obvious cause is found.


Article written by Dr Ronald Ng.