RESUMO
Substance Use Disorder (SUD) has been conceptualized as an outcome of a dysregulated reward system. However, individuals with SUD suffer from anxiety with an intensity depending on the abstinence period length. This review discusses the role of anxiety as a major contributor to the initiation and perpetuation of SUD, and its dependence on an up-regulated defense-antireward system. In addition, it is discussed that sleep debt, and its psychosocial consequences, promote anxiety, contributing to SUD generation and maintenance. Healthy sleep patterns can be disrupted by diverse medical conditions and negative psychosocial interactions, resulting in accumulated sleep debt and anxiety. Within this narrative review, we discuss the interplay between the motivation-reward and defense-antireward systems, framing the progression from recreational drug use to addiction. This interplay is nuanced by sleep debt-induced anxiety and its psychosocial consequences as contributory vulnerability factors in the genesis of addiction.