A false memory is a memory of an event that did not actually happen, or is a distortion of an actual experience. False memories can be highly vivid, just like normal memories, and are easy to implant.
False-memory syndrome (FMS) is a hypothesised state of mind where the sufferer has a high number of highly vivid false memories, often of abusive events during their childhood. FMS is not recognised in the DSM-IV.
This has been an important issue in many investigations, including cases of alleged sexual abuse and satanic ritual abuse. While accepting that not all abuses can be easily proved by external evidence, proponents of the theory of false memory syndrome suggest that it is possible for a person to manufacture false memories, often as the result of other stresses in their life such as anger or peer pressure.