Covert incest

Covert incest, also known as emotional incest, is a type of abuse in which a parent looks to their child for the emotional support that would be normally provided by another adult. The effects of covert incest on children when they become adults are thought to mimic actual incest, although to a lesser degree. This term describes interactions between a parent and child that are exclusive of sexual abuse.
Concept.
"Covert incest" was defined in the 1980s as an emotionally abusive relationship between a parental figure and child that does not involve incest or sexual intercourse, though it involves similar interpersonal dynamics as a relationship between sexual partners. Defining such relationships as "incest" has led to criticism of the concept for dramatically loosening the definition of incest, making child abuse seem more prevalent than it actually is and being overused and unsubstantiated.
Covert incest is described as occurring when a parent is unable or unwilling to maintain a relationship with another adult and forces the emotional role of a spouse onto their child instead. The child's needs are ignored and instead the relationship exists solely to meet the needs of the parent and the adult may not be aware of the problems created by their actions. 
The effects of covert incest are thought to mimic actual incest though to a lesser degree, and Kenneth Adams, who originated the concept, describes the victims as having anger or guilt towards parents and problems with self-esteem, addiction and sexual and emotional intimacy. Psychotherapist Roni Weisberg-Ross has noted that the term may not be particularly useful, since it can lead to attributing nearly any possible dysfunctional relationship or problem, becoming "a catchall, watered down diagnosis". Ross also criticizes the term for its emphasis on children meeting parents' "unmet needs", noting that children often meet the emotional or other needs of parents, with relationship boundaries frequently blurring and no definition of when this leads to permanent damage or harm.
Jungian analyst and author Marion Woodman describes covert incest as "unboundaried bonding" in which the parent or parents use the child as a mirror to support their needs, rather than mirroring the child in support of the child's emotional development. 
Alcoholism and other substance addictions are also associated with the occurrence of covert incest.