It's really interesting to hear someone else say this. I too have suffered occasionally from intense, violent nightmares. They don't necessarily continue all night, but the imagery is extremely disturbing, like a Hellraiser movie. I also took SSRIs like Paxil and Celexa in my early to mid twenties.
Recently, I've also begun experimenting with microdosing. I know almost nothing about the science of psychedelics but I've heard that they mimic the chemical structure of serotonin. I've also had a couple of intense nightmares recently. I wonder if there's somehow a connection between the effect of serotonin or things like it and the tendency to experience intense imagery in dreams.
Perhaps it's not exactly the quality (negative or positive) of the content but the intensity that is magnified. I think I could just as well say that I've had a number of intensely positive dreams while taking these substances but I can't speak objectively about it.