A 50-year-old man was admitted to our psychiatric clinic with symptoms of depression, comorbid neurological disturbances and cardiomyopathy. The condition was diagnosed as beriberi and Korsakov's syndrome, on the basis of thiamine deficiency. The patient's diet was unbalanced and restricted, but he was not an alcohol abuser. Thiamine suppletion led to a partial remission of symptoms. If a patient presents with depressive symptoms combined with neurological disturbances or heart irregularities, the Wernicke-Korsakov syndrome should be ruled out, even if the patient does not abuse alcohol. If in doubt, always opt for thiamine suppletion.