Gambling fever differs from gambling addiction in that in this state the player can still control himself, but under the influence of excitement he loses control of himself for a short time, as a result of which he can lose several bets in a row.
I don't see the difference between them. Both of them lose their self-control, they also gamble with unrealistic goals. And I'm sure there is no certain time period that gambling fever lasts. It is totally the same as gambling addiction. CMIIW 
Therapy is a waste of time when you are dealing with gambling addiction although some people think that it's a great way to get started on your journey of recovery but I don't really think that's true because gambling is a self made addiction or fever is self made and it can be stopped when you are determined to make sure it stops. The dopamine rush and all that doesn't have a mind of it's own, it can be controlled at any point
If the therapy is done by doctors or experts, I think it will be an effective way. Unless the therapy is carried out by the gambler himself, or it is done by random people. Sure, to make the recovery faster, it is better to stop gambling temporarily during the therapy process.