This thesis focuses on three critical phases in the life journey of a person with an opioid use disorder (OUD) ; Initial, random intermittent opioid use, termed ‘Recreational Sporadic Use’, transitioning to increased persistent opioid use, labelled ‘Intensified Sustained Use’, culminating in complete impulsivity and full opioid dependence, coined, ‘Loss of Control’. The crucial role of the neurobiology of dependence, explored in depth in this thesis, underpins these key phases in developing and sustaining an opioid dependence. Building on this framework the thesis unravels the effect of Adverse Childhood Experiences on the likelihood of experimenting with opioids and subsequently cultivating a dependence. It then recounts the effect of both dual diagnosis and concurrent benzodiazepine abuse on sustaining and intensifying one’s dependence until an individual eventually surrenders to the inevitable destructive effects of an opioid dependence and loses all voluntary control over their usage. The thesis then delves further into the lives of individuals with OUD by illuminating both positive and negative factors in their life journeys, which influence the remitting, relapsing nature of their illness. Invariably, given the neurobiological factors nourishing drug dependence the negative factors triumph, and relapse to drug use prevails.