Nah the sweet spot is to make the gambling companies pay for the treatment and recovery of the people addicted to their products, up to whatever amount they gave the gambling company.
Do they addicts have to self report to get treatment? Do we force them?
Food, tobacco, alcohol get more interesting... As there is bit harder time to assign blame of each meal. Maybe in those cases the claimants should be able to fully list everything they have ingested over say past 10 years. So that liability can be fairly and exactly distributed.
Betting companies employ all the tricks to make you a gambler. The more you loose, the more they target you. And if the gambler atops playing they literally go put of their way to nake them relapse.