False Memory by Dean Koontz

Martie Rhodes is a young wife and successful video game designer. Then one morning she experiences a sudden and inexplicable fear, a fleeting but disquieting terror of... her own shadow. Later she realizes that she is terrified to look in the mirror and confront the reflection of her own face. As these traumatic episodes build, the lives of Martie and her husband, Dustin, change drastically. Desperate to discover the reasons for his wife's sudden descent into mental chaos, Dusty takes Martie to the renowned therapist who has been treating her best friend, and begins a frantic search for clues. As he comes closer to the shocking truth, Dusty finds himself afflicted with a condition even more fearsome than Martie's.

No fan of Dean Koonts or of classical psychological suspense will want to miss this extraordinary novel of the human mind's capacity to torment - and destroy - itself.