This paper discusses the complexities of symptomatological psychotic disorders with particular emphasis on the paranoia and arising difficulties in their classification. The essential problems are: 1) their rich and varied psychopathology, 2) the unclear and spurious systems of classification, 3) the superficial definition of psychopathic syndromes and their diagnozed groupings. The diagnostic criteria of paranoid disorders in the International Classification of Diseases, Traumas and Cause of Deaths: ICD-9 and ICD-10 and also in the Classification of the American Psychiatric Association: DSM-III R and DSM-IV were considered and found to be inadequate.