Sadly it happens all the time and drugs are never involved. I know of one case whereby the father thought the mother was taking the baby to day care and the mother thought the father was taking the baby to daycare, the fatehr still is not the same 5 years later.
Not to thread jack, but here in Minnesota, the thin ice claims more than a few kids each year, several families lost all their kids. I have an older firend who says this NEVER used to happen when he was younger, you just KNEW not go go out when it was thin.