I believe this to be a dangerous oversimplification. An important goal of current neurobiological research is to understand the neuropharmacological and neuroadaptive mechanisms within specific neurocircuits that mediate the transition from occasional, controlled drug use and the loss of behavioral control over drug-seeking, and drug-taking that defines chronic addiction. Simply stating that narcotics are not inherently addictive ignores what we’ve learned (and have yet to learn) about epigenetic mechanisms. [see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3644540/ , http://pubs.niaaa.nih.gov/publications/arcr343/293-305.htm]
While research shows us that experience and environments influence addiction, the nature of an addict’s relationship to his/her drug of choice is also defined by neurochemical reactions [http://www.asam.org/quality-practice/definition-of-addiction, https://www.scientificamerican.com/article/rat-studies-elucidate-the/ , http://pubs.niaaa.nih.gov/publications/AA77/AA77.htm, https://www.ncbi.nlm.nih.gov/books/NBK53365/].