We already know that the brain under the influence of psychedelics has a tendency towards an overactive imagination. I'm not sure that is a specific clinical finding, but I've heard researchers comment in that direction.
From the abstract "Increased False-Memory Susceptibility After Mindfulness Meditation,"
participants were more likely to present false memories and had "reduced
reality-monitoring accuracy after completing the mindfulness induction.
These results demonstrate a potential unintended consequence of
mindfulness meditation in which memories become less reliable."
Another study found that participants given LSD were more suggestible, and that this was tied to the traits of absorption or immersion, as well as conscientiousness.