Substance use disorders (SUDs) are chronic, progressive, and treatable mental disorders that affect a person’s brain and behavior, leading to an inability to control the use of psychoactive substances, including cigarettes, alcohol, illicit drugs, and prescribed medications. The use of psychotropic substances—both adaptive, medicinal use and maladaptive overuse—has been ongoing for centuries. Substance use has increased exponentially in recent decades, posing great economic and social significance and, most importantly, increasing morbidity and mortality for millions of sufferers. SUD is now reckoned as an emerging national health concern, with over 20 million US citizens affected and deaths by overdose (OD) escalating (Weiss et al., Patient characteristics of opioid-related inpatient stays and emergency department visits nationally and by state. Agency for Healthcare Research and Quality, Rockville, p 224, 2017). According to the biopsychosocial model, psychological and biological factors interplay with social, economic, and cultural elements in the development and maintenance of SUDs. With this view in mind, SUDs can be conceptualized as biological diseases, psychological disorders, and social and cultural problems needing medical treatment and therapy, and caused, in part, by inadequate living conditions and a lack of social support. Despite advances in the understanding of SUDs, stigma still exists, highlighting the need to fight against criminalization and to develop policies that guarantee access to prevention and treatment.