APOE and Cognitive impairment: On the other hand, prior studies that reported the significant association either did not adjust for key confounders relevant to dementia [48–51] (such as educational attainment and APOE e4 status, and hence may not provide definitive conclusion on the association), or recruited community-dwelling individuals who possibly have had undiagnosed mild cognitive impairment [52–55] (and hence may not be representative of cognitively normal individuals with psychotic symptoms).