Psychiatry Research EG

About 23% of people with schizophrenia experience their first episode after the age of 40 [1,2]. Late-onset schizophrenia (LOS) is a controversial term with regard to both the age of onset (Z40 or Z50) and etiology and function. Although a recent International Consensus Statement [3] attempted to address inconsistencies in nomenclature and age cutoffs, it could only differentiate between LOS (onset between 40 and 60 years) and very late-onset schizophrenia-like psychosis (onset after 60 years) [4]. One of the controversies was whether the cognitive function in LOS was similar to or different from that of early-onset schizophrenia (EOS). Although some studies have reported an association between earlier age at onset and more severe cognitive deficits [5–7], others failed to find differences between the cognitive profiles of individuals with EOS and those with LOS [8–10]. Further, the nature of the cognitive deficits that may be associated with age at onset varies in different studies Some studies found that individuals with LOS seem to have some relatively preserved cognitive functions such as arithmetic, digit symbol coding, and vocabulary. Further, assessing semantic organization, Paulsen et al. [11] reported that individuals with LOS (age at onset 445 years) were preserved compared with individuals with EOS. In contrast, a meta-analysis carried out by Rajji et al. [12] reveals that participants with LOS are severely impaired with regard to measures of auditory and visual attention, fluency, global measures of cognition, intelligence quotient, and visuospatial construction, more so than individuals with youth-onset schizophrenia or first-episode schizophrenia for most of these measures. In Egypt, although 6% of the population is aged above 60 years, which expected to reach 11.5% by the year 2025 [13], there are few studies on clinical profile, function, and cognitive dysfunction of LOS. Hence, this study tested the hypothesis that LOS had cognitive impairment that differed from that of EOS in pattern and severity. Thus, we aimed to describe the profile of cognitive impairment in LOS and compare it with that in EOS with regard to pattern, severity, and its effect on daily function.