Screening for cognitive impairment in schizophrenia: Psychometric properties of the German version of the Screen for Cognitive Impairment in Psychiatry (SCIP-G)

BACKGROUND: The Screen for Cognitive Impairment in Psychiatry (SCIP) is a brief scale designed for detecting cognitive deficits in patients with psychiatric disorders including schizophrenia. In this preliminary study the psychometric properties of the German version of the SCIP are examined in a sample of patients with schizophrenia and schizoaffective psychosis (DSM-IV) as well as in healthy controls. METHODS: Thirty patients and thirty matched controls were asked to complete two versions of the SCIP separated by two-week intervals in addition to psychiatric and neurocognitive instruments including assessments to measure psychosocial functioning. Feasibility, reliability and validity of the SCIP were examined in order to determine parallel reliability. The convergent validity was assessed by the BACS (Brief Assessment of Cognition in Schizophrenia) and the MMSE (Mini-Mental-State-Examination). RESULTS: Significant differences in cognitive performance between patients and healthy controls were detected in both versions of the SCIP. The SCIP effectively discriminated between patients and the control sample. The reliability of the parallel versions of the SCIP was supported by high correlations between the alternate forms, and by the high internal consistency of SCIP subtests within the patient sample. Construct validity of the SCIP was supported by high correlations between the SCIP and the BACS total scores, and by high correlations with common cognitive domain scores from the two tests. CONCLUSIONS: Our data show that the German version of the SCIP (SCIP-G) is a brief, valid and reliable assessment tool for the detection of cognitive impairment in patients with schizophrenia or schizoaffective psychosis.