One popular 'dark psychological light novel' is 'Another'. It has a really creepy and mysterious atmosphere. The story is full of unexpected twists that play with the characters' and readers' psyches.
'Durarara!!' is worth mentioning. It delves deep into the minds of its diverse characters in an urban setting. There are elements of mystery, psychological games, and complex relationships. The story unfolds in a non - linear way, which adds to the overall sense of intrigue and the exploration of the darker aspects of human nature.
'Baccano!' is also a great one. It weaves a complex web of stories and characters with a touch of dark psychology. The way the different plotlines intersect and the characters' motives are explored is quite fascinating. It's a novel that keeps you on your toes as you try to piece together the whole picture.