From the study of Kane et al. (1988), devoted to clozapine, a critical analysis of criteria of assessments about studies in treatment of resistant schizophrenic patients was drawn up. Therefore, among the inclusion criteria, the authors strengthen the necessity of a very long past neuroleptic treatment (beyond six months) before diagnosing a resistance, the "drug-free improvers" characterized by improvement when patients had been treated by a placebo, the necessity of a very long placebo wash-out (beyond six weeks), and the improvement by a second treatment after a first ineffective treatment. Moreover, the doses of neuroleptics opposed to clozapine are often too high leading to adverse effects and so decreasing the positive benefits. For instance, the dose of chlorpromazine is often increased to 1,800 mg/day whereas the doses required should be only 600 mg/day in equivalence to 500 mg/day of clozapine. Lastly, the scales more specific of the symptomatology of schizophrenia such as SANS-SAPS or PANSS should be used in the clinical trials whereas until now, all the studies were made by standard and global evaluations with BPRS, CPRS and AMDP.