Simple schizophrenia is a sometimes controversial diagnosis. Here we review the concept with particular reference to its history in diagnostic systems. Using an illustrative real case of a 25-year-old man, we show that there is a need to retain this diagnostic category, which may fit better within proposed dimensional (psychomotor poverty, disorganisation and reality distortion) rather than categorical classifications of schizophrenia. Symptoms of the disorder may be better revealed by functional assessment than by relying on descriptive psychopathology.