"what specific laws ...?"

If a company chooses a design and it can be proved through a subpoena of their communications that the design was intended and chosen for its addictive traits, even if there has been no evidence collected for the addictiveness, then the company (or person) can be deemed to have created a design in bad faith to society and penalized for it.

(Well that's my attempt. I tried to apply "innocent until proven guilty" here.)