I believe that almost any discipline or hobby can become an addiction if not managed properly. While poker doesn't entail a chemical dependency (meaning, there aren't substances in the game itself that cause addiction like certain drugs do), addiction can still develop when the brain releases certain hormones as a reward for winning money or gambling. That's my understanding, although I'm not a professional in that field.
Additionally, if you're not good at accepting the fact that you could lose money, things can end badly, especially if you're investing money you can't afford to lose. It can lead to a complicated situation.
As long as there isn't a dependency, everything should be fine.
