Addiction isn't a cause of gambling is an effect
Many join for entertainment / fun while most for money.
So I would say it should be because of poverty
People are always looking for ways to make more money
And with the success stories surrounding gambling
Many get hooked to try their luck.
I strongly agree with this, addiction is a result of something that they experience.
So if the choice would only be addiction or bad economy it would definitely be the bad economy.
But those who could think straight wouldn't even start gambling when they don't have enough to cover all of their expenses.