It goes deeper than that. People who have completely given up on life with no hope or direction.
I think the no hope or direction usually comes later, after enslavement. Drugs start out as party fuel — a social enhancer. Funny how that is because once hooked, it is a very lonely state even when done with others. And the choice factor — the human will — is relinquished early on. It becomes the person’s master.
The couple smelled of drugs, drugs were found on them, and the guy was out on probation. There is a long history that led to their closet dwelling.