Oniomania (from Greek onios = "for sale" : coined by German psychiatrist Emil Kraepelin) also known as shopping addiction or shopaholism, is the compulsive desire to shop. Although not a DSM-IV recognized disorder, oniomania has recently received increased media attention. Similar to other compulsive behaviors, sufferers often experience the highs and lows associated with addiction. The purchase generates a mood of satisfaction for the addicted, seems to give their life a meaning and lets them forget about their sorrows. Usually back at home the feeling of a personal reward has already gone. To compensate, the addicted person goes shopping again. The bought goods will be hidden or destroyed, because the person concerned feels ashamed of their addiction and tries to conceal it. Without psychotherapy this disorder can persist a whole life or until the financial ruin of the addicted person.
http://en.wikipedia.org/wiki/Shopping_addiction