I definitely think there is a reason to be worried. Replacing one substance for another is a warning sign. Using to escape reality (Although a lot of people do it) is usually considered a breeding ground for addiction and it's typically unhealthy in itself.

I believe that people can get addicted to weed. Anything pleasurable is subject to addiction (but obviously some aren't as addictive as others).

Family history is also a very relevant deciding factor.
Be careful.