Substance-related disorders are the most frequent comorbidity in schizophrenia. Concretely, alcohol is the most commonly consumed substance after tobacco. Patients with schizophrenia with this comorbidity have a worse clinical course and can develop serious neuropsychiatric complications. One of them, Marchiafava-Bignami disease (MBD) can be incorrectly diagnosed as a decompensation of their mental disorder.