Violent videogames can increase aggression and hostility in some players but they can also benefit others by honing their visual/spatial skills and improving social networking ability, scientists said.

In a special issue of the journal Review of General Psychology published by the American Psychological Association, researchers said the games can also help to control diabetes and pain and work as a tool to complement psychotherapy.

Violent video games are like peanut butter, said Christopher J. Ferguson, of Texas A&M International University. They are harmless for the vast majority of kids but are harmful to a small minority with pre-existing personality or mental health problems.

He added that studies have revealed that violent games have not created a generation of problem youngsters.

Recent research has shown that as video games have become more popular, children in the United States and Europe are having fewer behavior problems, are less violent and score better on standardized tests, Ferguson, a guest editor for the journal, explained.

Patrick Markey, of Villanova University in Pennsylvania, found in a study of 118 teenagers that certain personality traits can predict which children will be negatively influenced by videogame.

If someone is easily upset, depressed and emotional or is indifferent to the feelings of other people, breaks rules and fails to keep promises, they may be more likely to be hostile after playing violent videogames.

These results suggest that it is the simultaneous combination of these personality traits which yield a more powerful predictor of violent video games, Markey said. Those who are negatively affected have pre-existing dispositions, which make them susceptible to such violent media.

But on a more positive note Pamela Kato, of University Medical Center in Utrecht in the Netherlands, showed in her research that specially tailored games can help to prevent asthma attacks, and ease pain management and diabetes treatment.

T. Atilla Ceranoglu, of Massachusetts General Hospital in Boston, discovered in a research review that videogames can also be used in psychological assessment of children and teenagers.

(Reporting by Patricia Reaney; Editing by Paul Casciato)

Pennsylvania