At the risk of sounding like a chest puffer, my first three published books, which came out in the late nineties, were all classified as supernatural thrillers by the publisher (Harper Collins)...basically thrillers with a supernatural element. And the first one drew comparisons to Dean Koontz, which was the highest element of praise I think I've ever gotten.
Okay, let me unpuff now. If you want to read them, they can be had for as little as one cent used on Amazon since they are all out of print now. The titles are Cold White Fury, Eyes of Night, and Second Sight.
When the first one came out (Cold White Fury) Ingrams catgegorized it as horror because it had a paranormal element to it and that was how they defined horror. As a result, it was shelved in the horror section in most bookstores. Book #2 (Eyes of Night) hints at a supernatural element but is more of a straight thriller and as such, got shelved that way. It made for an interesting dilemma since my first two books were often found in different parts of the store rather than next to one another. Second Sight had a much lighter paranormal element to it and for some reason ended up in the mystery sections of most stores. Go figure.
Some called my books genre hybrids or cross genre books. This label had its pros and cons. One of the biggest pros was a broad appeal across several spectrums of readers. One of the biggest cons was the above mentioned identity crisis, which often made it hard to find the books. If a mystery reader found Second Sight in that section of the store and liked it, then went looking for another mystery by the same author, they wouldn't find one, at least not in the mystery section. Internet sales sights, like Amazon, eliminate some of that confusion because it's so much easier to search for works by the author's name.
There has been a surge in paranormal stuff across all genres lately, including romance, so having a paranormal element doesn't automatically place a book in the horror class anymore.
Beth