Phasic and process psychoses: a polydiagnostic comparison among the Frankfurt Classification System, DSM III, RDC,...

The classification of endogenous psychoses is a controversial sector of psychiatry. Differences with regard to the evaluation of course and outcome contribute to this controversy. The course and outcome of a psychiatric illness are basic to the Frankfurt Classification System (FC) of endogenous psychoses. The main groups are process and phasic psychoses (typical and atypical). A third group, encompassing cases which could not be definitely classified at the time of examination, is entitled 'nonclassified endogenous psychoses'. This system was outlined according to the AMDP system and SANS using the cases of 100 patients admitted to the hospital (aged 18-86 years; 57 men, 43 women) and compared with four classifications (ICD-9, RDC, DSM III and Feighner). The listed definitions do not state whether or not a defective symptomatology is absolutely irreversible. Most of the atypic-phasic psychoses of the FC (50-78%) were schizoaffective psychoses according to the other classifications (Feighner, RDC, ICD-9) and most of the process psychoses (85-97%) were schizophrenias according to Feighner, ICD-9, RDC and DSM III. The major reason for the great correspondence (97%) between process psychoses (FC) and DSM III schizophrenias appears to be that 85% of the sample consisted of chronic and not subchronic schizophrenic disorders according to DSM III. On the other hand, about 45% of the ICD-9 and RDC schizophrenias (principally acute and subacute) were not diagnosed as process psychoses according to the FC. In the case of the typic-phasic psychoses, there was almost complete agreement with the other diagnostic systems. Most of the cases in which classification into the group 'process' or 'phasic psychosis' was unclear were diagnosed as schizophreniform disorders according to DSM III (70%) or into nearly equivalent groups according to RDC or ICD-9. Nonetheless, complete equivalency among these similar groups was not possible. In the context of some research aims (e.g. definitions of phenomenological or biological parameters), a classification system based on clearly-defined inclusion and exclusion criteria of such concepts as phasic and process psychoses (in shifts or insidious) is methodologically useful. The FC is suggested as a step in this direction.