Worry and anxiety problems can have a major impact on people's sleep patterns and thus have an adverse effect on their quality of life.
Dr Sarah Jarvis, resident doctor on BBC1's The One Show, stated that up to 86 per cent of individuals with general anxiety disorder (GAD) have difficulty sleeping at night.
She explained that one in 20 have GAD, which usually starts in the mid 20s and is twice as likely to affect women as men.
Dr Jarvis said: "The vast majority of people with GAD have difficulty getting to sleep purely because of worry or anxiety."
The condition is difficult to treat because the symptoms are "soft" and as well as reduced sleep can include restlessness, irritability, muscle tension and concentration problems.
Anyone who has had sleep problems more often than not for a sustained period of around six months should make an appointment to see their GP to ascertain the mental causes of their problems, she recommended.