Niemann-Pick disease, a neurovisceral lysosomal lipid storage disorder, is a rare disorder that is unknown to many clinicians. The disease, that often has its onset during childhood or adolescence, shows a polymorphic clinical picture, including psychiatric symptoms. Because of its infrequence, Niemann-Pick disease is diagnosed with an average delay of 6 years. This report presents a case of an adolescent male whose symptoms had led to various hospitalisations and psychiatric diagnoses. When he presented with psychotic symptoms in our department, thorough diagnosis revealed Niemann-Pick disease type C1 as the underlying disease.