Are late-onset schizophrenia spectrum disorders neurodegenerative conditions? Annual rates of change on two dementia measures.

Some investigators assert that emergence of schizophrenia spectrum disorders in mid- to late life (LOSD, i.e., onset after age 45) reflects neurodegenerative processes. The authors examined 1- and 2-year changes among 37 outpatients with LOSDs on the Mini-Mental State Examination (MMSE) and Mattis Dementia Rating Scale, compared with 69 patients having earlier-onset schizophrenia spectrum disorders (EOSD), 67 having Alzheimer's disease (AD) with psychosis, 72 having AD with baseline MMSE scores >/=24, and 56 normal comparison subjects (NCs). Cognitive changes among LOSD patients were similar to those in EOSD patients and NCs, whereas the AD groups had greater declines. Results support viewing LOSDs as static encephalopathies.