Simple Schizophrenia: A Forgotten Diagnosis in Psychiatry.

Clustering of symptoms to characterize simple schizophrenia is still debated, and support is needed for the characterization of simple schizophrenia as a syndrome. We conducted a systematic review to identify all cases of simple schizophrenia published until December 2017. We identified 42 cases of simple schizophrenia, 57% of which met all three diagnostic criteria (ICD-10, DSM-4 research criteria, and Black and Boffeli's criteria for simple schizophrenia). The mean age at first contact with clinical services was 30.1 (SD = 11.6) years, with a mean delay of 7.4 (SD = 6.8) years from symptom onset to first presentation. An insidious onset and negative symptoms were characteristic features in all cases. Social withdrawal, alogia, blunted affect, lack of initiative/interest, and functional impairment were found in more than 85% of cases. Our findings contribute to greater awareness and understanding of simple schizophrenia, and have the potential to reawaken interest in this clinically distinct subgroup.