Kleptomania refers to an irresistible urge to steal items that have no personal or financial bearing to the one committing the act. Persons with kleptomania typically feel a strong pressure prior to the act, which is then relieved after the theft is accomplished. A person suffering from Kleptomania would be unable to resist the temptation to steal an item, say a scarf seen at the mall, even if they themselves never wear scarves, and can easily pay for the item. They get a thrill not from having the item itself, but from the act of stealing it.
First medically described in the early nineteenth century, it is now classified as part of either an impulse-control disorder, or (controversially) as part of the spectrum of obsessive-compulsive disorders and is most often comorbid with other disorders like anxiety, eating disorders and/or substance abuse.