Whether playing video games has negative effects is something that has been debated for 30 years, in much the same way that rock and roll, television, and even the novel faced similar criticisms in their time.
Purported negative effects such as addiction, increased aggression, and various health consequences such as obesity and repetitive strain injuries tend to get far more media coverage than the positives. I know from my own research examining both sides that my papers on video game addiction receive far more publicity than my research into the social benefits of, for example, playing online role-playing games.
However there is now a wealth of research which shows that video games can be put to educational and therapeutic uses, as well as many studies which reveal how playing video games can improve reaction times and hand-eye co-ordination. For example, research has shown that spatial visualization ability, such as mentally rotating and manipulating two- and three-dimensional objects, improves with video game playing.