Abstract :
Late-onset schizophrenia (LOS) is likely a syndrome of diverse etiology, for which the newer neuroimaging methods can address 2 questions. First, to what extent are the brain changes documented in “classic” early onset schizophrenia seen in late-onset cases? Second, can brain imaging techniques be used to subtype or classify cases of LOS? Data will be presented from a series of related preliminary studies in which we compared LOS patients with normal controls, elderly patients with early-onset schizophrenia (EOS), and Alzheimerʹs disease patients. We used quantitative magnetic resonance imaging (MRI) and neuroreceptor positron emission tomography measures, which had previously been reported to be abnormal in EOS. EOS and LOS patients showed similar MRI changes. LOS drug-naive patients had elevated Bmax (receptor density) values for dopamine D2 receptors compared with age and gender norms, a phenomenon previously reported by our group in young schizophrenia patients. Broadening the definition of LOS to include patients with fewer “classic” schizophrenic symptoms, such as Schneiderian first-rank symptoms, appeared to increase the number of “organic” cases, particularly of cerebrovascular disease.
