Ethnicity as a variable in mental health research: a systematic review of articles published 1990-2004

The objective of the study was to investigate how the ethnic variable has been used in mental health research, in theory, in measurement and classification criteria. Journal articles published 1990-2004 that address original research on psychopathology, treatment and mental health services and with "ethnic" or "ethnicity" in their title or abstract were selected. The papers were examined for their theoretical definition of ethnicity, how the ethnic data were collected and the criteria used to identify ethnic groups. The use of comparison groups and country of the studies were recorded. A total of 421 papers were identified. An explicit theoretical definition was found in 33 (7.8%) papers. Data collection procedure was mentioned in 248 (58.9%) and 104 (24.7%) papers described how data was converted into ethnic groups. The operationalizations of ethnicity have remained almost unchanged during the 15-year review period. Generally, the ethnic variable was incompletely reported. Confusion regarding which individual or social characteristics ethnicity refers to makes the research findings of limited value in clinical settings, and may continue to create misunderstanding about the effect of ethnicity in clinical contexts.