I used to think it was a chain reaction that started with my violently abusive husband, which in turn cause so much anxiety that I couldn't keep food down which cause anorexia and that really causes a lot of hormonal and body chemistry reactions that leads to altered states.

But after therapy I realized it was there in HS, and both the childhood sexual abuse and my deafness impacted me much more than I was aware of. They said a lot of things I talked about in childhood was dissociative symptoms. I was diagnosed PTSD w/ depression first. The inability to keep food down exacerbated everything but then when they added the antidepressants I lost years of my life. I'm with jimi I was telling them the meds were making it worse but was told no and they added more stuff that caused a lot of black outs.

So, mostly I'd have to say it was nurture for me. Oddly the family doc sent me to the mayo clinic for a suspected brain tumor ( I was losing weight and had horrible migraines)when I was nine but I never told them what was going on. They did want to have me see a therapist but my father was aghast at the idea of any of his kids seeing those crazy docs. I've often wondered what my alternative time line might be like if I had gotten help back then? Hindsight is 20/20.