Just to add to the discussion a little here, many of my gothic mystery novels exist on a horror/thriller spectrum, and in some cases the lines are very blurred. Spectre of Springwell Forest and The Irresistible Summons definitely operate more at the horror end, whereas The Birds Began to Sing and Phantom Audition are much more like psychological thrillers. The Thistlewood Curse sits firmly in the middle, starting as a detective story, developing into a supernatural thriller, and finishing as full-blown horror.

I've always been very partial to stories that evolve into horror tales. In film, good examples include Kill List and, a personal favourite, Angel Heart.

Outside the gothic mysteries, I've also dabbled in genre blending in a few other areas. One novel I wrote entitled Love vs Honour begins as a teenage romance, with a girl from a Muslim background and boy from an evangelical Christian background meeting on holiday and falling in love. To remain together, they undertake an elaborate deception where they pretend to convert to one another's respective religions. Over time, ironically, they are genuinely drawn to these faiths, with the girl converting to Christianity and the boy converting to Islam. Complications ensue, leading to a much darker final act. The narrative goes from romance to comedy-drama, to something a lot more intense in the finale.