[Image via Dave Bedrosian/Future Image/WENN.]
We guess only Rob Kardashian knows the truth!
According to sources, the famous fam believes Kardashian has slipped back into old habits of excessive partying alone in his room. The theory isn't too audacious considering R.K. was once caught indulging in sizzurp and weed back in 2014.
Despite the clan's worries, Rob claims he's very much sober. In fact, he believes he's doing better than ever before now that he's dating Blac and taking advantage of her home gym.
Insiders claim the brood isn't buying the 28-year-old's denials since Chyna was just arrested for possession of ecstasy.
So, do YOU think Rob is using?