The potential harmful effects of excessive caffeine consumption remain largely unknown among psychiatric populations. Energy drinks have particularly high levels of caffeine content and have previously been shown to induce psychotic relapse. Clinical observations of three bipolar disorder patients with comorbid substance use disorder revealed an excessive consumption of energy drinks prior to manic or depressive relapse.? Three patients with bipolar spectrum disorder and comorbid substance use disorder were assessed by a psychiatrist upon re-admission to a rehabilitation centre following manic or depressive relapse. The assessment was based on DSM-IV criteria and performed by a psychiatrist who specialized in bipolar spectrum disorder and comorbidities to determine the presence of manic or depressive relapse. Two patients were diagnosed with bipolar disorder type I, and the third with bipolar disorder type II. All three patients were diagnosed with comorbid substance use disorders and all three abused cocaine.? In all three cases, relapse occurred following at least one week of excessive binging on energy drinks, with a maximum daily consumption of nine cans. Following cessation of energy drink consumption, two of the patients remained abstinent from drug use and maintained psychiatric stability. One patient relapsed three months post-treatment and resumed consuming cocaine and energy drinks.? These clinical observations support other case reports that suggest the existence of a potential correlation between excessive energy drink consumption and relapse among psychiatric populations.