Suicide because the sun does not set

Many people hate gloomy days in the winter because they cause seasonal depression syndrome. However, the sun hovering in the sky for many days can also cause much more frightening consequences.

Midnight sunset scene in the north of Greenland island.Photo: theodora.com.

To the north of Denmark's big island Greenland, more than 80% of suicides occur in the summer - the period when the sun never sets. "There is too much light and the people here cannot stand it ," said Karin Sparring Björkstén, a scientist at the Karolinska Institute (Sweden).

Björkstén and colleagues studied the 1,351 suicides from 1968 to 2002 in Greeland - the island that most of the area is in the Arctic Ocean. When examining data by month, experts found suicides occurred more frequently in the summer, especially in the north - where the sun rarely dives during the summer.

Of the 33 cases that killed themselves at Avannaa (Greenland's farthest northern region), 27 died on March 7 to October 8. That is the time when the sun shines all day and night. (Avannaa has disappeared from the map since early 2009 after the Danish government redistributed the administrative boundary on Greenland).

80% of suicides on Greenland Island are male. 95% of victims end their lives with violent means (such as hanging, jumping, shooting). There is no evidence that they drink much alcohol or suffer from depression. Researcher Björkstén believes that continuous exposure to the sun during the summer makes people fall short of sleep.

'People on Greenland Island are different from the rest of the world in the summer. Farmers came to the field in the middle of the night, while the children played in the hours before dawn. Their normal biological cycle is turned upside down , "she explained.

Other countries do not have to suffer from the 24/24 sunrise in the summer like Greenland, but people can draw many things from the Karolinska Institute's research. 'In industrial society, people tend to not care about sleep. The number of sleeping hours is decreasing, while the working time increases. Clearly, the 24-hour life span is not good for us. The cost of medical treatment will be reduced if people pay more attention to sleep , 'Björkstén added.