Introduction <p>The practice of chemsex refers to the use of drugs during sexual activities. Many articles describe chemsex practices and address the risks of sexually transmitted infections; however, few address the topic of addictive patterns of chemsex in terms of diagnostic criteria, predisposing factors, and recommended treatments. Drugs commonly used in chemsex practices include the new synthetic cathinones 3-methylmethcathinone and 4-methylmethcathinone. Knowledge about the addictive properties of 3-methylmethcathinone and 4-methylmethcathinone, as well as the therapeutic possibilities for addiction to these drugs, is still very scarce in the literature. The current case report addresses this gap from a clinical perspective.</p> Case presentation <p>This case report describes the situation of a 37-year-old white European man suffering from chemsex addiction with 3-methylmethcathinone intake. We suggest a model for conceptualizing chemsex addiction as a compulsive sexual behavior disorder coupled with addiction to one or more substances, while taking place in a particular sociocultural context. We provide a description of the collected clinical symptoms and of the personalized psychotherapy and pharmacotherapy treatment interventions that yielded the patient’s recovery.</p> Conclusions <p>We highlight the relevance of our conceptualization model for abstinence from synthetic cathinones for sexualized purposes, through the lens of the patient’s positive response to the fit-for-purpose treatment strategy: personalized psychotherapy and bupropion pharmacotherapy. Finally, we emphasize the importance of carrying out studies that can scientifically validate the predisposing factors, the diagnostic criteria, and the treatments for chemsex addiction. These elements are essential to think about when it comes to adequate public heath interventions for at-risk individuals and groups.</p>