Background: Breastfeeding is one of the best ways to promote, develop, and secure the health of infants. Child abuse is one of the most common and most important problems in the world, and one of the factors that increase its incidence is substance dependency of the parents. Breastfeeding beyond the normal age range can be harmful to the health of the mother and baby, and may represent a pathological parent-child relationship. Case Report: A little girl, who was breastfed until the age of 8 years by her heroin-dependent mother, was hospitalized in a child and adolescent psychiatric ward due to heroin dependency. During the investigations, it was found that not only had the girl been breastfed until this age, but she had also not been enrolled into a school. In other words, due to the mother’s heroin dependency, her infant was also dependent on the drug. Conclusion: In the assessment and treatment of parents with substance related disorders, the possibility of child abuse should also be considered. When breastfeeding is continued beyond the normal age range, it is necessary to find the reason. By early detection and timely intervention, negative consequences for the child can be prevented.