Despite the availability of many treatment options, several individuals with bipolar disorders experience persistent symptoms, necessitating the exploration of novel therapeutic approaches. In recent years, there has been a growing interest in repurposing drugs of abuse, such as stimulants, ketamine, and psychedelics, for the treatment of bipolar disorders. While some of these drugs have demonstrated promising efficacy in clinical trials, concerns regarding their potential risks have emerged. This chapter investigates the complex relationship between repurposed drugs of abuse and bipolar disorder, examining both the potential benefits and in particular the associated risks. This will include a discussion of the potential for addiction, exacerbation of existing psychiatric symptoms, and adverse physical and cognitive effects. We will engage in a balanced risk–benefit analysis, weighing the potential benefits of repurposed drugs of abuse against the associated risks. This will involve a consideration of the severity of bipolar disorders, the availability of alternative treatment options, and the potential for individualized risk stratification. This analysis will inform clinical decision-making and guide future research endeavors in this rapidly evolving treatment field.