Verification of forensic functionality of two psychiatric classification systems (ICD 8 and ICD 10), determination of similarities and differences between them, and evaluation of difficulties in subsuming particular psychiatric diagnoses into legal categories.

The retrospective method was used, based on comparison of the information from forensic psychiatric expertises made in the Center for forensic psychiatry, Vrapce Psychiatric hospital in Zagreb, in two periods: during 1968 and 1995, chosen at random up to the total of 300 expertises related to criminal law. The shortened version of standardized FPDS (Forensic Psychiatric Documentation System) questionnaire was used, which was modified for the purpose of the study and, due to the necessary reduction of the data for statistical analysis, the questionnaire was additionally shortened to the final version which consists of 51 items.

The basic hypothesis that there is a difference in the level of forensic functionality of the two classification systems compared in this study was only partially confirmed. The other hypothesis, that psychiatric classification system ICD-10 is more functional in forensic psychiatry than classification system ICD-8, is not completely confirmed either. The questionnaire can be also used in other similar studies for evaluation of forensic-psychiatric expertises. The results can be of help in everyday practice in forensic psychiatry, in the field of expertise and in the field of forensic psychiatric treatment.