Numerous neuroscientific researches studies have proved that addiction is a brain disease, and behaviour of an addict is the result of a functional damage of brain structures responsible for decision-making, strategic thinking, planning and experiencing pleasure, which leads to frequent relapses unless the addict is undergoing pharmacotherapy. Due to their high addictiveness, opiates, especially heroin, cause severe physical and mental addiction after only one month of regular use. Addicts mostly live in a primary or secondary family, so the consequences of addiction as a disease affect all family members. Aetiology of addiction is related to several factors, which are most often intertwined. Some of the most significant factors are family dysfunctionality, bio-psychological inclination, characteristics of one’s environment related to availability of drugs, influence of peer subculture, entertainment trends, quality of school and prevention programmes. As the basic unit of society, family plays a significant role in the protection of children, while parenting styles and influence of various social circumstances play an important role in personality development. Research shows that the most common types of parenting styles in which addicts are brought up are the following: authoritarian, overly permissive or maladjusted to the needs of the child. Treatment is a years-long process. Establishing psychobiological functionality of the brain through pharmacotherapy is a prerequisite for including an addict in a course of treatment. Such treatment is conducted by a multidisciplinary team in which a nurse plays a significant role as the person who welcomes the addict and their family to the treatment process. Within that process, family therapy is crucial and family therapist assumes the role of an “outside” associated family member that takes part in the process and objectively observes, analyses and evaluates family relations, encouraging change with better quality and functionality of relationships in mind.