What can I do to reduce or prevent hypnagogic hallucinations? I understand its not real but they are terrifying and vivid and disrupt sleep 1x per wk.

Polysomnogram. Hello. There is not an easy answer for this. It would be very important to see a sleep specialist and to obtain a polysomnogram (sleep study). This will help to identify your sleep abnormalities accurately -so that a specific treatment plan can be developed. Take care.