Playing video games like Warcraft can boost some aspects of cognitive function, such as reaction time, complex reasoning and visual memory, said Dr Gary Small, a psychiatry professor in the United States and director of the University of California, Los Angeles' Longevity Centre.
"In moderation, video games can be fun and represent another form of social interaction."
It is only when gaming becomes excessive that it may have a negative impact on face-to-face communication skills or emotional and social intelligence; or lead to less time spent on physical exercise, he said.
"We have shown that simply searching online will alter neural networks after just one week, one hour a day," said Dr Small.
"All these activities have brain and cognitive effects. The question is whether the effects will be positive or negative, and that depends on the extent of use and the nature of the mental activities involved in the use."
What parents should take note of is the suitability of the games for their child,
Dr Ong Say How, a senior consultant and chief of the department of developmental psychiatry at the Institute of Mental Health, said children and young adults are more vulnerable to media influence, unlike adults who are more mature cognitively and have a stronger sense of morals.
"For a child or a young teenager, if he keeps watching violent or sexual scenes, he becomes sensitised to them and may reenact them in the real world," he said.
"People think that teenagers are mature, but they are not. Studies have shown that your brain is fully mature only in your mid-20s."
Online games may help develop certain skills. "You have better hand-eye coordination and are probably more agile with your fingers, but is there a lot more to it?" said Dr Ong.
In theory, video games can be dispensed with, but many people enjoy them too much, said Dr Small.
The key is to balance screen time with activities away from the screen, such as physical exercise, social interactions and other experiences that support brain health, he said.
A child needs to have recreational activities every day and these should not be restricted to Internet games, said Dr Ong.
Screen time has to be balanced with other forms of social and physical activities, so as to allow the child to learn new skills that the computer cannot teach, he said.
Screen time guidelines
Key recommendations on screen time from the American Academy of Pediatrics (AAP):
• For children younger than 18 months, avoid the use of screen media other than video-chatting.
• Parents of children aged 18 to 24 months who want to introduce digital media should choose high-quality programming and watch it with their children to help them understand what they are seeing.
• For those aged two to five, limit screen use to one hour a day of high-quality programmes. Parents should watch the programmes with children to help them understand what they are seeing and apply it to the world around them.
• For children aged six and older, place consistent limits on the time spent using media, and the types of media, and make sure media does not take the place of adequate sleep, physical activity and other behaviours essential to health.
• Designate media-free times together, such as dinner or driving, as well as media-free locations at home, such as bedrooms.
• Have ongoing communication about online citizenship and safety, including treating others with respect online and offline.
• The AAP has an interactive, online tool for families to create a personalised family media-use plan.
Key recommendations on screen time from the Royal College of Paediatrics and Child Health:
• Families should negotiate screen time limits with their children based on the needs of each child, the ways in which screens are used and the degree to which use of screens appears to displace (or not) physical and social activities and sleep.
• Screens should be avoided for an hour before the planned bedtime.
As a guide to examine their screen time, families can ask these four key questions:
1. Is screen time in your household controlled?
2. Does screen use interfere with what your family wants to do?
3. Does screen use interfere with sleep?
4. Are you able to control snacking during screen time?