Does Munchausen Syndrome by Proxy only apply to a parent (caregiver) and his/her child (care receiver)? Or does it apply to any relation between a caregiver and a care receiver with that kind of behavioural pattern?
Munchausen by proxy has been diagnosed for caregiver/care receiver relationships that were not parent / child. Munchausen by adult proxy is an article reviewing 13 cases found in the medical literature where the care receiver in the relationship was an adult. Not all of the perpetrators were parents.
The perpetrator was the victim's mother in 3 cases, wife in 2 cases, son in 2 cases, and daughter, granddaughter, husband, companion, boyfriend, or prison cellmate in 1 case each. Five (38%) worked in healthcare.
From Munchausen Syndrome by Proxy :An Adult Dyad
Although well-documented in the child and adolescent literature, few case reports document MSBP with an adult proxy
The majority of cases seem to be underage children and parents (usually mothers), though.