Nature and course of cognitive function in late-life schizophrenia: a systematic review.

OBJECTIVES: To systematically review the literature on the nature and course of cognition in late-life schizophrenia (LLS).
METHODS: We conducted a literature search using Medline. Search terms included schizophrenia, cognition, memory, and other cognitive search terms. We limited our search to age 45 and above. All titles or abstracts were read, and relevant papers were reviewed. Only cross-sectional studies with healthy control groups or longitudinal studies of cognition in LLS are presented in this review.
RESULTS: We identified 23 publications reporting on cross-sectional studies comparing cognition in subjects with LLS and healthy controls, and 19 publications reporting on cognitive changes during longitudinal follow-up. The cross-sectional reports suggest that patients with LLS are most consistently impaired in executive function, visuospatial ability, and verbal fluency. Impairment has less consistently been observed in memory, attention, and working memory. Longitudinal studies suggest that patients with LLS start to decline cognitively around the age of 65, and that this decline may first affect visuospatial abilities. However, most of these studies have been conducted in institutionalized patients, rather than the typical ambulatory population. Other limitations include small sample sizes, short follow-up periods, and lack of comprehensive neuropsychological assessments.
CONCLUSIONS: The existing literature suggests that the nature and course of cognition in LLS is heterogeneous. Larger and longer studies using both comprehensive and specific cognitive assessments are needed to understand the causes and consequences of this heterogeneity.