Using a timer to restrict online time is a possible approach. The science fiction novel "The Ringworld Engineers" by Larry Niven (1980) features one Louis Wu,

Using a timer to restrict online time is a possible approach. The science fiction novel "The Ringworld Engineers" by Larry Niven (1980) features one Louis Wu, who at the beginning of the story has become a 'wirehead' (wireheading being "the act of directly triggering the brain's reward center by electrical stimulation of an inserted wire, for the purpose of 'short-circuiting' the brain's normal reward process and artificially inducing pleasure.") He manages it by use of a specially designed timer which requires several hours of painstaking work to reset.