Although it should be used only in small quantities, at the legal amount of 0.3 percent or less, THC can help reduce nightmares and therefore further improve quality of sleep. This is especially true for PTSD sufferers, because the traumatic events that they saw, heard and experienced, can have lessened influence overall, with better sleep. THC does affect brain chemistry by producing a euphoric and more relaxed feeling.
The two components of CBD and THC can also have a beneficial outcome, by producing an entourage effect, where they work together to have the correct balance of restfulness and alertness, with equal amounts of both, or an adjusted dosage of each one on its own, with more CBD than THC. This combination is more likely to produce the desired effect.