Some people may be genetically programmed to require longer hours of sleep, according to a new study published in Molecular Psychiatry. The study hopes to reveal the health effects of different sleeping patterns.

Approximately 10,000 people, from the Orkney Isles, Croatia, the Netherlands, Italy, Estonia and Germany, took part in a study that found those with the gene ABCC9 needed 30 minutes more sleep, per night, than those without it.

The subjects were questioned on sleep patterns for free days - when they did not need to get up for work, take sleeping pills or work shifts.

The researchers, who were from the University of Edinburgh, Scotland, and the Ludwig Maximilians University in Munich, Germany, compared these figures with the results of the subject's genetic analysis. The researchers also looked at how the gene works in fruit flies. Apparently flies without ABCC9 slept three hours less than normal.

Humans sleep for approximately one-third of their lifetime. A tendency to sleep for longer or shorter periods often runs in families despite the fact that the amount of sleep people need can be influenced by age, latitude, season and circadian rhythms, said Dr. Jim Wilson, from the University of Edinburgh's Centre for Population Health Sciences.

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