Teenagers need about 8-9 hours of sleep per day. After puberty, it is normal for teenagers to develop a sleep phase delay in their normal sleep patterns so that they fall asleep later at night and wake up later in the morning. Unfortunately, sleeping longer at weekends creates a situation similar to jetlag by Monday morning because of the shift in circadian rhythms. These normal sleep disturbances can make teenagers excessively tired, irritable, impatient and depressed.

Sleep problems are common in teenagers. In the short term, lack of sleep in teenagers can increase their susceptibility to illnesses, like colds, flu and gastroenteritis. Lack of sleep in teenagers can then be linked to high cholesterol, obesity, depression and risky behaviours.

So it's a good idea to try and help your teenager to get enough sleep.

Set a regular bedtime and wake-up time every day. (It will be difficult to follow this on weekends and holidays, but it is worth trying.)

Restrict exposure to blue light in the evenings, which includes energy efficient light bulbs, mobile telephones, tablets, computer screens and blue or green digital alarm clocks. Blue light effects melatonin production, and melatonin is strongly linked with good sleep.

Encourage your teenager not to make themselves available 24 hours a day on their telephones, email and social media accounts. Negotiate clear limits for time spent using information technology devices. Ensure your teen has a sleep-friendly environment, a dark, cool and quiet room, will encourage better sleep.