1. Side Effects (2013). A young woman's world unravels when a drug prescribed by her psychiatrist has unexpected side effects.
2. Black Swan (2010). A ballet dancer wins the lead in "Swan Lake" and is perfect for the role of the delicate White Swan - Princess Odette - but slowly loses her mind as she becomes more and more like Odile, the Black Swan.
3. The Machinist (2004). An industrial worker who hasn't slept in a year begins to doubt his own sanity.
4. Jacob's Ladder (1990). Mourning his dead child, a haunted Vietnam vet attempts to discover his past while suffering from a severe case of disassociation. To do so, he must decipher reality and life from his own dreams, delusion, and perception of death.
5. Memento (2000). A man, suffering from short-term memory loss, uses notes and tattoos to hunt for the man he thinks killed his wife.
6. Frailty (2001). A man confesses to an FBI agent his family's story of how his religious fanatic father's visions lead to a series of murders to destroy supposed "demons."
7. Rosemary's Baby (1968). A young couple move into a new apartment, only to be surrounded by peculiar neighbors and occurrences. When the wife becomes mysteriously pregnant, paranoia over the safety of her unborn child begins controlling her life.
8. Identity (2003). Stranded at a desolate Nevada motel during a nasty rainstorm, ten strangers become acquainted with each other when they realize that they're being killed off one by one.
9. Dead Again (1991). In 1949, composer Roman Strauss is executed for the vicious murder of his wife Margaret with a pair of scissors. In 1990s Los Angeles a mute amnesiac woman shows up at an orphanage and private eye Mike Church is called in to investigate. Under hypnosis both the woman and Church seem to have a strange link back to the Strauss murder.
10. The Last Seduction (1994). A devious sexpot steals her husband's drug money and hides out in a small town where she meets the perfect dupe for her next scheme.
Bonus film: Repulsion (1965). I haven't actually seen this, but it is by the director of Rosemary's Baby (and Chinatown), and was supposedly a big influence on Black Swan. The trailer is a hoot: