Man, my mind immediately jumps to Harlan Coben's standalone thrillers for this. They're practically built on that foundation—an ordinary person's life gets torn apart by a disappearance or a secret from the past, and the suspense is all about the psychological unraveling. 'Tell No One' is maybe the ultimate example; the protagonist's obsession with his wife's supposed death feels so claustrophobic.
If you want something a bit more... feral in its psychology, try Gillian Flynn. 'Gone Girl' is the obvious pick, but 'Sharp Objects' digs even deeper into the psychological damage of the protagonist herself while she's investigating a kidnapping. It's less about the physical chase and more about the mental contamination, which can be even more gripping.
For a slower, dread-filled burn, Tana French's 'In the Woods' might work. It ties a childhood abduction trauma to a present-day murder investigation, and the way it explores memory and guilt is masterful. The resolution divides people, but the build-up of psychological tension is undeniable.