[Ethnic minorities and aggressive behaviour in psychiatric in-patients: an investigation using a "Matched-Pair" design].

In a group of 105 mentally ill immigrants we investigated the intensity and the frequency of aggressive behaviour at the time of admission with the help of two standardized instruments: the "Social Dysfunction and Aggression Scale" (SDAS) and the "Modified Overt Aggression Scale" (MOAS). As many as possible collateral informants were contacted to gather all information available for the aggressiveness rating. The immigrant group was compared to a matched group of German patients. 416 German patients had to be investigated until 105 of them fulfilled the matching criteria. The matching variables were: age, gender, diagnosis (ICD-10), severity of mental illness (CGI) and social status. The physicians who carried out the matching process and who carried out the aggression-rating were "blind" to the aim of the investigation. We found out that there was no significant difference between immigrants and German patients when the sum-scores of the SDAS and the MOAS are compared (N = 210). When SDAS single variables were compared German patients had a higher severity and frequency of "physical violence towards other persons". We interpreted this finding as an increased level of disinhibition which may be correlated to a higher acceptance of aggressive behaviour in German culture compared to normative beliefs of Mediterranean immigrants.