Paranoid psychosis and classificatory system Despite advances made in the nosology of DD, the plethora of current definitions reflects a lack of consensus. The rea sons could be that DD occur infrequently, the patient con- tinues to function and live in the community without ever seeking treatment, and minimal overt identifying characteris- tics leading to misdiagnosis. The concept that DD is distinct from schizophrenia and mood disorder has recently been recognized by many psychiatrist Manschrek (2000) has given a lucid description of developments in the classificati- on of DD, the summary of which is provided below. DSM System: The DSM-I & II (APA, 1952 & 1968 defined paranoid reactions as conditions with persecutory or grandi- ose delusions but generally lacking hallucinations. The sub- types were- Paranoia (a chronic disorder with systematized delusions) and Paranoid state (a more acute, less persistent condition with less systematized delusions. The DSM-III (APA, 1980 established new definitions, but earlier concepts were still evident in the essential features of paranoid disor der as persistent persecutory delusions or delusional jealously not attributable to any other mental disorder; included were paranoia, shared paranoid disorder, acute paranoid disorder and a residual category atypical paranoid disorder. A sub division was provided by duration of symptoms: a duration of more or less than 6 month ted paranoia from acute paranoid disorder. The drawbacks of DSM-III were: the