Many years ago, my cousin and his wife rented a house outside Philadelphia that they swore was haunted. Footsteps echoed in an empty bedroom, a cold spot could be detected at the top of the stairs, and cosmetics and hairbrushes levitated. I confess: I was frightened by these reports of paranormal activity and never visited that house, but my cousin and his wife were nonchalant. “I always say you need to fear the living more than the dead,” my cousin shrugged after telling me about an old woman in black who suddenly materialized in his kitchen one afternoon.

Ha! Fear the living more than the dead? Lisa Unger knows better. As she dramatizes in her latest psychological thriller, “Crazy Love You,” the dead are always way more dangerous than the living — craftier, slipperier and far less concerned about the legal consequences of their bad behavior

Ian Paine, the deeply flawed hero, learns this truth the hard way. A successful graphic novelist, Ian enjoys his spacious loft in Tribeca and the steady adulation of fans at Comic-Con every year. He’s celebrated for his fantasy series, Fatboy and Priss, which recounts the adventures of an overweight misfit and the gorgeous supernatural she-demon who wreaks vengeance on the bullies and brutes who try to make Fatboy’s life a misery. The catch is that Ian’s books aren’t complete fantasy. Indeed, they owe a lot to his own lonely childhood in a creepy upstate New York burg called “The Hollows.” Ian’s mother was mentally disturbed and his father remote. After tragedy struck the family, Ian turned to a steady diet of junk food for comfort, ballooning into a jumbo target for middle-school sadists. His only friend was a small girl named Priss, whom he met one day in the woods, “rail thin and pale, but with a wild head of red hair.” They regularly played hide and seek, climbed trees, and talked. Soon after they became friends, bad things — usually involving catastrophic fires — happened to anyone who hurt Ian. Priss always had his back.

And still does. Even now, when Ian has grown up into “a fairly-decent-looking-moderately successful guy,” Priss — who has also blossomed — continues to turn up at odd moments. The adult incarnation of Priss is a fiery, vengeful seductress who watches out for Ian, but also jealously demands his full attention. Now that he has fallen for a quintessential nice girl named Megan, Priss — whoever or whatever she is — is very unhappy.

Unger serves up all the standard entertainments of the psychological suspense tale, along with the bonus delights of sharply drawn characters and occasional rest breaks of humor. Is Ian really haunted by an unpredictable ghost named Priss, or is she just a psychotic projection of his fevered imagination? That’s the crucial question Unger manages to keep aloft throughout most of a novel that nervously jumps around in time from the gloom of Ian’s childhood to the frantic present, when a resentful Priss (or perhaps a disturbed Ian?) seems hell-bent on destroying his career and personal life. Unger is adept at evoking the eerie, but she’s also capable of droll sociological commentary on the urban scene. Here, for instance, is Ian’s first sighting of Megan, who’s working as a nanny. He shrewdly deduces that despite her nanny outfit of jeans, ballet flats and scrubby ponytail, she is a child of privilege:

"Crazy Love You" by Lisa Unger. (Touchstone)

“She came from money; she had nice, concerned parents probably living somewhere close by. How did I know this? There’s a way a woman carries herself, a shine, an inner cleanliness, when she comes from love and privilege. It takes a certain amount of confidence to walk around Manhattan looking like a bit of a mess. She was pretty, probably smoking hot under those baggy clothes. She could have shown it off like every other beautiful girl in the city. But she didn’t need to; she didn’t care who was looking. And you don’t feel that way, not ever, unless your parents told you and showed you how special you are. That’s how I knew.”

Before “Crazy Love You” is over, Megan’s signature “shine” and “inner cleanliness” are destined to become a bit bedraggled, courtesy of a hair-raising investigative trip to The Hollows. After reading Unger’s sinister thriller, anyone cavalier enough to think they can easily put the past to rest (and even live companionably with the dead) will think again.

Corrigan, who teaches literature at Georgetown University, is the book critic for the NPR program “Fresh Air.”

CRAZY LOVE YOU

By Lisa Unger

Touchstone. 338 pp. $25.99