The only thing I know of is working on processing your trauma in therapy... If you can't do that or just need something temporary while you're doing the work, (this isn't a proven method by any means) but I used to put on audio books or meditation podcasts to sleep with in hopes it would keep my brain occupied while I slept. It won't solve the root problem though.

Personally, I was given advice that in my nightmares I had to address the person responsible for the evilness in my dreams. It was hard for me at 1st...took me a long time. But it works! And the traumatic events that happened I have to use grounding statements as soon as I wake up or if I get flashbacks...like I'm okay, I'm not hurt, I see white walls, blue carpet, or whatever I see by looking around the room, I smell.... i hear.... etc etc.

I've been dealing with this for a very long time. I definitely would say I have chronic nightmares that are due to trauma. The things that help me the most are meditation before bed and I realize that some of my medication actually causes nightmares so I stopped taking those. But yeah I definitely recommend for preventative measures to use a meditation before bed my favorite is "the honest guys" on YouTube.. if you just had the nightmare I recommend giving yourself reassurance and thinking about how the dream should have gone in a better way. That's what they recommend military people do for their nightmares. I also use cannabis after if my nightmare is bad enough.

I have had nightmares for a long while or I did. I tried all non pharmaceutical ways to not have them. Nothing worked. My psychiatrist put me on prazosin and they went completely away. The only bad part was when I thought I could get off them because I was healing well but they returned once I stopped. If no other therapeutic methods don’t work maybe you could try that.

I get horrible nightmares from time to time from my past relationships and I have to use my unconscious mind when sleeping to remind myself that time in my life is over and reality check myself while a sleep. Example iam happily married now and if he isn't in my dream as my hero I know iam experience a nightmare.

Maybe while awake identify your safe person. Nightmares are based on thoughts we fall asleep with or having in our unconscious mind.