That is one of the things that causes depression, emagine using money that was meant for another thing important for gambling and loss it in that process. Of course such person will not be happy.
I think you're very correct about that, and of course losing the money that is meant for important stuffs to gamble is not always that easy for one to sake it out of his head. Though the very first time that the temptation will come you will still find it very hard to figure out that you're being tempted, not until when you finally fall for the temptation that's when you will still realize that you are being tempted in the first place.
That’s one of the reasons it's necessary to know your budget before you gamble, if you gamble out of curiosity, you might end up on experiencing depression, because you might not gamble with what you can afford to lose, but when you gamble with plans you will not experience the negative side of gambling, if you lose, you have joy and if you win you will also have joy, because the money you used is budgeted to gamble.