Non-medical prescription use of opioids (NMPUO) is a public health concern worldwide. Recently, tramadol misuse is increasing, but the systematic research of misuse of this specific opioid is limited. This study set out to assess the relationship between tramadol use and completion of treatment for substance use among adolescents and adults ≤ 25 years in an outpatient clinical setting. A retrospective cohort study of treatment outcome, expressed as “completion” or “non-completion” of treatment, was conducted in treatment-seeking adolescents with problematic substance use (n = 335). Data was extracted from Ung-DOK interviews, a semi-structured assessment instrument designed for adolescents with substance abuse. The study included all treatment-seeking patients at an out-patient facility in 2014–2017. A total of 26% (n = 88) were tramadol users (life-time prevalence). Twenty percent (n = 66) of all treatments were non-completed. Tramadol users were significantly more likely than non-users to drop out of treatment (35% vs 15%, p < 0.001). In multivariate logistic regression, tramadol use and age 18 and above were factors significantly associated with non-completion. Tramadol use was statistically significantly associated with non-completion of treatment. Further research addressing treatment needs and treatment completion among tramadol users is needed
