Scott Stapp's downward spiral continues ... he has lost custody of his 3 kids.
A Florida judge has ruled ... the former Creed frontman's soon-to-be ex-wife Jaclyn will have sole legal and physical custody of their 3 kids. There's no indication from the ruling that Scott even gets visitation.
The judge also ruled Scott has no right to stay in the family home -- it's exclusively for Jaclyn and the kids.
Scott has been off the rails for a while ... Jaclyn says he's delusional because he's taking a pharmacy of drugs, including coke, weed and meth. She's trying to get him involuntarily committed for 60 days.