DS1(just three) has v extreme night terrors (definitely not nightmares). They are just like the standard descriptions (appears awake but screaming, in fact deeply asleep, nothing helps other than to wait for it to end) but they happen very often, and on a bad night every 90 minutes all night, not just once at the beginning. I have a few other concerns about him and I'm wondering if anyone has any idea whether this is known to be a sign of other problems and if so what? I hope it's ok to ask here. I tried posting on sleep a few weeks ago buy had no responses.