There is evidence to indicate that 15 % of patients diagnosed as schizophrenic will become chronically hospitalized, and that worldwide one-third to one-half of all psychiatric beds are occupied by schizophrenic patients. In spite of these figures and the public health problem they represent, little attention is paid to chronic hospitalized schizophrenic patients. Even the most recent classification schemas fail to recognize the heterogeneity, exemplified by differential responsiveness to psychotropic drugs, within the chronic schizophrenic population. One systematic approach to classification which does address this problem has been proposed by Leonhard. In this paper, findings and procedures that demonstrate the clinical relevance of Leonhard’s system along with some preliminary results and observations from psychopharmacological studies that indicate Leonhard’s different subtypes of chronic schizophrenia may represent biologically distinct populations are presented.