Evidence supporting the use of a brief cognitive assessment in routine clinical assessment for psychosis

Cognitive impairment is a core feature of psychosis. Full cognitive assessments are not often conducted in routine clinical practice as administration is time-consuming. Here, we investigated whether brief tests of cognition could be used to predict broader neurocognitive performance in a manner practical for screening use in mental health services. We carried out a principal component analysis (PCA) to obtain an estimate of general cognitive function (N = 415). We investigated whether brief tests of memory accounted for a significant percentage of variation in the PCA scores. We used discriminant function analysis to determine if measures could predict classification as lower, intermediate or higher level of cognitive function and to what extent these groups overlapped with groups based on normative data. Memory tests correctly classified 65% of cases in the highest scoring group, 35% of cases in the intermediate group, and 77% of cases in the lowest scoring group. These PCA-derived groups and groups based on normative scores for the two tests were significantly associated (χ2 = 164.00, p < 0.001). These measures accurately identified three quarters of the low performing group, the group of greatest interest from the perspective of identifying those likely to need greater supports as part of clinical care. In so doing they suggest a potentially useful approach to screening for cognitive impairment in clinical services, upon which further assessment can be built if required.