I'm jewish am i more susceptible to becoming an addict?

No: Whether it be ashkenazy or sephardic there is no genetic predisposition towards addiction. There are also no cultural or societal correlations in the literature.

Probably less: There are moderately strong cultural barriers to jews becoming addicted. For instance alcoholism is very low among jews. It is not a matter of heredity but of social convention. Some young jews do defy these conventions and addiction is possible.