When gamers play frequently there's a decrease in prefrontal lobe activity. This can lead to altered moods and aggression behavior, which can last even after the game is turned off.
One week of violent game play can lead to lower activation of left interior frontal lobe during emotional tasks and also anterior cingulate cortex during numerical tasks.
Those who play aggression games are significantly more anxious those who don't.
Playing violent games increases aggressive thoughts, feelings, and behaviors in the short and long-term.
Long term playing can lead to obesity, attention problems and poor school performance.
POSITIVE EFFECTS
Games that require teamwork help develop collaboration skills.
Improves ability to reason and solve new problems independently of previous acquired knowledge.
Can improve peripheral vision, way-finding skills, hand-eye coordination and mental rotation.
MALE GAMERS VS. FEMALE GAMERS
On average, male brain show a much greater activation in mesocorticolimbic center (associated with reward and addiction) than female brains. This amount correlated directly with how much advancement they made through the game-play.