Playing computer games for more than seven hours a week can leave you sleepless, and vulnerable to health problems, say scientists.
The doctors believe that the bright light from computer screen may suppress the natural production of melatonin and alter the body's clock.
Melatonin hormone helps regulate a person's sleeping and waking hours.
The new study showed that gamers - both male and female - who play for more than seven hours a week, sleep less during weekdays and experience greater sleepiness than casual players or non-gamers.
Psychologist Dr Amanda Woolems of the University of Arkansas said that the current study supports previous findings that obsessive gamers spend less time in bed, take longer to get to sleep and have shorter periods of REM sleep - when we are most relaxed.
"Our statistics revealed those who admitted addiction (to gaming] scored higher on a sleepiness scale," the Scotsman quoted her as saying.
Dr Woolems said there was "a significant positive correlation" between the hours of game play and sleepiness.