how about high dose cbd

The short version: high-dose CBD is where the real side effects live, and the sleep evidence at high dose is thin and mixed.

The dose question matters because CBD's harms scale with dose. A meta-analysis of randomized trials found any-adverse-event risk rose with dose, and the liver signal was concentrated in high-dose trials above 20 mg/kg/day, mostly in childhood epilepsy [1]. Withdrawal from trials for any reason was about 2.6 times more likely on CBD, and serious adverse events roughly 2.3 times more likely, driven by the epilepsy group [1]. Outside epilepsy, serious events were rare [1].

For sleep specifically, the one high-dose trial here is a combination, not CBD alone: 200 mg CBD plus 10 mg THC in insomnia patients actually reduced total sleep time by about 24 minutes and cut REM sleep, versus placebo [2]. That is the opposite of what people buy it for. The high-dose epilepsy data show real seizure benefit in a severe pediatric population [3], but that is a different disease and a different risk calculus.

What this evidence cannot see: no trial here tests high-dose CBD alone for sleep in healthy adults. That gap is real, and it is the study that would settle it.

My call: high-dose CBD is not a sleep aid I would recommend, and the dose-dependent liver and dropout signals are the reason to be cautious, not the marketing. Confidence: moderate.