Not being able to fall asleep and instead lie down and worry about not being able to sleep is a big problem for many, and if it lasts for a long time it is called chronic insomnia.

- It is important to seek help and get a diagnosis, says Dieter Riemann who is a professor of psychophysiology at the University of Freiburg, Germany.

Pensive nights

Many years of long and brooding nights erode the ability to deal with problems. It increases the risk of becoming depressed, suffering from cardiovascular disease and also increases the risk of developing an alcohol dependence.

And the cure is there, namely to learn to resist the thoughts that disturb the night's sleep.

- In cognitive therapy, we examine what kind of thoughts grind at night. Many describe it as a movie. The thoughts come automatically when you are between wakefulness and sleep and then you are not able to handle the thoughts, they play with you, says Dieter Riemann.

Negative thoughts

One way to ward off these often destructive thoughts is to think for a good while before going to bed if something negative has happened during the day and which you may have wanted to forget. Negative thoughts that are depressed tend to come back when we go to sleep.

- Confront these thoughts when you are completely awake, otherwise they will come and chase you to bed, says Dieter Riemann.

He also recommends asking yourself if what you are worried about at night really corresponds to reality. Many people think that they should not function at work the day after a night of insomnia.

- But is that really true? Write a sleep diary and check how things are going at work on the days you experience that you have had difficulty sleeping. Usually there is no connection, insomnia does not affect your ability to perform. For example, those who suffer from insomnia are rarely involved in car accidents, says Dieter Riemann.

Hide the alarm clock

 Dieter Riemann has more strategies against insomnia: Hide the alarm clock so you do not worry about time. Try not to drink alcohol in two weeks. If you are awake, get up and do something else that is relaxing. Test for lack of sleep, go to bed late and sleep only five hours.  

- You sleep better the longer you have been awake, says Dieter Riemann.

 More about sleep in Vetenskapens Värld on Monday 17 August 20.00 in SVT2 or on SVTplay from Sunday 16 August.