INSOMNIA refers to when someone has difficulty getting to or staying asleep.
One third of Brits will have episodes of the frustrating condition at some point, the NHS says.
Occasional stints of sleeplessness may come and go without causing any serious issues.
But for some people it can last for months, or even years at a time.
Long-term sleep issues can have a huge impact on your quality of life – and even your health.