The use of alcohol or drug(s) prior to self-injury is a possible inducing factor for suicidal self-injuries among patients with adjustment disorder. We analyzed the cases of 175 individuals who were admitted to the intensive care unit (ICU) of Tokyo Medical and Dental University Medical Hospital for suicidal self-injury to determine whether alcohol consumption or an excessive use of prescribed psychotropic medications prior to self-injury is more common in patients with adjustment disorder. During a 7-year period (July 2006 to June 2013) following their deliberate self-injuries, 971 patients were admitted to the ICU. Our study sample (n=175) was restricted to patients with adjustment disorder (n=48), major depressive disorder (n=90), or schizophrenia (n=37). The outcome variable was alcohol consumption or excessive use of medications prior to suicidal self-injury. A logistic regression analysis revealed that the patients with adjustment disorder more commonly showed alcohol consumption or excessive medication use prior to their suicidal self-injury compared to those with schizophrenia (odds ratio: 8.10; 95%CI: 2.97-24.60). To inhibit suicidal self-injury among patients with adjustment disorder, it is important to continue efforts to provide psychoeducation about alcohol use and to instruct the patients to take their prescribed medication(s) only as directed by their physician.