• toddlers need about 12–14 hours’ sleep (including daytime naps)

• pre-schoolers (aged 3–5) need 11–12 hours’ sleep

• school-age children need 10–11 hours’ sleep

• teenagers need 9–10 hours’ sleep.

• Very young children often fear being left alone at night. This is called ‘separation anxiety’ and is normal at a young age.

• Bedtime fears – many young children are afraid of the dark.

• Bad habits – napping too much during the day.

• ‘I'm not sleepy’ – you might find that when your child gets very tired, they get irritable, aggressive or even overactive (hence the phrase ‘overtired’).

• Large tonsils and adenoids at the back and sides of the throat can cause breathing difficulties that can wake a child many times each night. The child may not remember waking up, but you may notice that they snore loudly and sleep restlessly. This is called obstructive sleep apnoea. An operation to remove the tonsils and adenoids may be needed.

• Restless legs syndrome is a condition where the child complains of crawling feelings or ‘growing pains’ in their legs that make them want to keep moving them, which stops them getting to sleep.

• Narcolepsy is an unusual condition that causes unpredictable attacks of sleep during the day. People with narcolepsy may also have sudden attacks of weakness – this is called cataplexy.

• In teenagers, drug or alcohol misuse is sometimes a factor.

• Some young people who have depression sleep more than usual.