Some trauma isn't obvious to the victims. Like if a parent never emotionally connected with their children but still provided shelter, food, etc. Trauma can also be disguised under (pick your ideology / religion) and therefore the victim doesn't call it trauma. Other people experience trauma and the way their mind adapts is by forgetting. You'll often hear about these people remembering shocking things that no "normal" person would forget, like sexual abuse.

Also, trauma and drugs could be two of several ways of becoming open to the other world. Another could be genetic. Or there could be multiple other worlds or different categories of spiritual beings, some people susceptible to some and others to others.