An Evaluation of Two Screening Methods to Identify Cases with Schizophrenia and Affective Disorders in a Community Survey in Rural Ethiopia

Background: Detecting cases with psychiatric disorders in the general population is costly and it is not clear which is the method of choice for community surveys in low-income countries. Aim: To compare the performance of a standardized diagnostic layman interview instrument-the Composite International Diagnostic Interview (CIDI 2.1) versus the Key Informant method in identifying cases with schizophrenia and major affective disorders in a community survey. Method: Both screening methods were tested against an expert interview the Schedule for Clinical Assessment in Neuropsychiatry (SCAN 2.1) in a rural district in Ethiopia with 25,632 inhabitants. Result: CIDI identified 524 and key informants 192 individuals as probable cases who were invited for a further SCAN interview. Seventy-two individuals were identified by both methods. Of those identified as probable cases by either method, a total of 481 volunteered the SCAN interviews. The Key Informant method alone detected more cases of schizophrenia, 59 vs. 29 for CIDI, whereas CIDI alone detected more cases of affective disorders, 45 vs. 30. Key informants performed better in detecting chronic cases. Conclusion: For community surveys, which aim at identifying cases with major mental disorders in low-income countries like Ethiopia, the combined use of both CIDI and the Key Informant method is recommended.