Chulalongkorn Medical Journal


Introductions : Persons with schizophrenia have a clear association with increasedviolence in community than the general population. At present, therehas not been any scale developed to estimate risk of violence,particularly in persons with schizophrenia.Objectives : To develop a clinically useful for evaluation violence risk amongpersons with schizophrenia, and to carry out an initial validation ofthe scale.Setting : Out patient department of a psychiatric hospitalResearch design : Instrument developmentSample : Persons with schizophrenia who had committed violence (n = 300)Methods : A 29-item Thai Violence Risk Scale (TVRS) was constructed onthe base of the literature review and Psychology of Criminal Conduct(PCC) as guideline for selection of significant characteristics andcircumstances that are risk factors associated with violence amongpersons with schizophrenia in community. Scale developmentprocedures composed of 10 steps guide by Crocker and Algina.Content validity of the TVRS was evaluated by nine content experts,internal consistency was evaluated with Cronbach alpha, andconstruct validity was evaluated with exploratory factor analysis (EFA).Results : The number of 29 items in the item pool of the first draft of the TVRSwas reduced to 27 items in content validity step with an I-CVI scoreranged from .78 - 1.0 and an S-CVI/Ave score of .86. After completingitem analysis, the number of 27 items in the second draft scale wasreduced to 17 in this step. Cronbach’s alpha coefficient of thesecond draft scale was high (= .92). Findings from the EFA(varimax rotation) showed that the TVRS was composed of 2 factors.Factor I was the characteristics (15 items) and factor II was thecircumstances (2 items).Conclusions : The suitability of development procedures of the TVRS that seemsto be clinically and practically useful in identifying persons withschizophrenia in community with a particularly high risk for violence.


Faculty of Medicine, Chulalongkorn University

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