This is long, but the topic hits close to home and I thought maybe someone else might have had a similar experience and/or have more information.

It's a nightmare if you find the content to be unpleasant.

It seems to me like there's a difference between "unpleasant" dreams and "nightmares" (terminology aside).

I'm just speculating here, but, for instance, you might dream your SO dumped you or you were late to work, and it's uncomfortable and unpleasant, but not the same kind of "unpleasant" as being chased by an axe murderer.

I've often wondered if these different types of "unpleasant" dreams come from different places (mentally) and/or "serve different purposes" (biologically, I guess?).

Into my mid-20s, I experienced what they now call "night terrors". I still had the occasional "normal" nightmares, but the terrors were very different.

My poor ex. I would sit up in the darkness and desperately whisper things like, "Baby, wake up! Wake up . . . there's a man at the foot of the bed. He's coming for us!"

I'd even lay out rational arguments in my defense.

I'm not asleep! I swear! I'm wide-awake! Please listen to me! Someone is in the house!

I would be 100% convinced that our survival depended on him believing me. Sometimes I would sob or violently "defend" against the imaginary intruder.

One time, my son was sleeping next to me and I hallucinated that someone was standing over him. I grabbed the lamp from the nightstand, climbed over him, and smashed it to pieces against the wall. So, you know, freakin' traumatized my kid. At least he knows mom will defend him to the death should it ever come to that!

The terrors typically included a component of being watched, hunted, or something similarly terrifying. But, sometimes, I'd calmly sleepwalk or carry on conversations as if I was fully awake. I didn't always remember it later.

I smashed the garage door trying to drive in my sleep. Being a responsible adult, I took precautions and installed an alarm system. One night, I opened the front door, the alarm went off, I reset it in my sleep and walked out. I was found sitting in the driveway like I had good sense. My mom had to stay with me until the problem subsided.

Sometimes, I was literally paralyzed. Back then, I thought I was "paralyzed with fear" (that's what it felt like), but I discovered later that it was due to waking during a natural state that prevents us from hurting ourselves by moving around in our sleep.

I laugh about it now, but it was actually very serious at the time. I worried I would hurt a loved one.

I still have dreams like I showed up nude to work, forgot to study for a test (yep, 15+ years out of college and I still have those dreams), etc.

But, those earlier experiences were very different. It makes me wonder if different brain functioning is responsible for each. I'm not sure if that makes any sense . . .

There's a film on iTunes right now called "The Nightmare" about night terrors, but IMHO, it's just dumb. The stories in the film did sound a lot like mine, which was interesting. But, I'd been hoping for insight into the science behind it and the film focuses on the "mysticism" surrounding it. I'm not under the impression that demons or aliens are visiting me in the night.

Side note for anyone who experienced night terrors in the past: I've always had migraines. Recently, I've had body pain all over, chest pains, and other health issues. The docs ordered a sleep study and it showed I wasn't fully entering REM sleep. Evidently, this can cause major physical problems. The doctors are taking it very seriously.

One doctor told me that although they're not sure what causes it, it's reported that many people who suffered night terrors as children have similar health issues later in life. They think it's caused by a related sleep problem. So, if you had night terrors in the past, get things checked out. Don't wait like I did. You may be missing sleep or sleep cycles and not even know it at first.