What happens to a child's mental health if their parents are both drug addicts?

Prenatal exposure : to tobacco, drugs & alcohol disrupts fetal brain development from 3 wks. post conception on. Dad adds 2nd-hand smoke of any inhalant. Depending on mom's drugs of choice, intrauterine "strokes" & growth restriction further damage an atypically developing brain. Genetic predisposition for mental illness & addiction, unsafe environment & inconsistent, often abusive, parenting yield poor outcomes.

Leads to neglect: When both parents are addicts, there is a high likelihood of the children using drugs as well. Parents who are involved with drugs tend to be neglectful of their children and provide a very poor model for the children's development.