It's a syndrome as opposed to a disease, which has a well-defined cause. It's a constellation of symptoms, which you've heard described repeatedly, and it's much more referred to in the forensic and law enforcement community than it is in the medical community. There's been lobbying by the American Psychiatric Association to include it in the DSM-IV, which is their diagnostic and statistical manual of psychiatric diseases, but as the cause is not well established, there's been reluctance to do that.
On April 28th, 2008. See this statement in context.