Some fruit juices have very high potassium content. However, only several cases of juice-induced hyperkalemia have been reported that involved non-psychiatric, diabetic outpatients with renal compromise. We present a highly unusual case of a 66-year-old non-diabetic, schizophrenic woman with psychogenic polydipsia and normal renal function who developed hyperkalemia secondary to excessive orange juice consumption while an inpatient. In addition to demonstrating this previously undescribed medical comorbidity of schizophrenia, this case highlights the need for careful attention when communicating with both nursing and patients when managing psychogenic polydipsia.