The period between the ages of 0 and 25 is a crucial phase in human development, during which many aspects of physical, psychological, personality, behavioral and health development take place. Important neurobiological changes during adolescence play a key role in their natural propensity to seek reward, putting them at greater risk of different kind of addictive behaviours. In addition, childhood adversity can foster the emergence of vulnerabilities which, for some, increases the risk of addiction by the time they reach adolescence. This article describes the normal development of the brain from childhood to adulthood, and its influence on addictive behaviours.