I believe we can only say someone is addicted to gambling when the gambler has started to act stupid by not realizing he's loosing more than his Incomes and haven to gambling without plans with zero self control. Moreover gambling is basically an entertaining events while it has the chances of profit returns.

Trading is strictly a financial instrument with an obligation of traders to be successful in it while developing good trading strategies and persistence is the key word to reach the goal.
You can perhaps be addicted when you also have lost your mind out of it probably when greeds has been applied or when trading ignorantly and just depends your success on lucks instead of knowledge without being able to identify when you're going right so you can necessarily adjust to it. Especially when it gets to do with knowing the right mental and environmental conditions to trade.