Internet addiction in the wired generation

According to recent figures, about twice annually, a gamer dies. In January 2015, A 32-year-old man was found dead in an internet cafe in Taiwan. In September that same year, a Russian teenager died after playing Defence of the Ancients for 22 consecutive days. Usually young and male, their demise is caused by a lack of sleep and/or movement, following a multi-day online gaming binge. These people are almost certainly internet addicts, per the DSM-5 definition. But how do you know if a child has, or is at risk of developing, this potentially deadly obsession?