Late-onset schizophrenia

The diagnostic status and pathophysiology of late-onset schizophrenia continue to be controversial issues. The goal of our research program has been to study clinical, neuropsychological and MRI characteristics of late-onset schizophrenia. As comparison groups, we have studied patients with early-onset schizophrenia and a normal group of subjects, all over age 45. The total number of subjects studied to date has been over 250. The results show that late-onset schizophrenia is a clinically valid diagnostic entity. Late-onset schizophrenia shares a number of clinical, neuropsychological and nonspecific MRI characteristics with early-onset schizophrenia. Late-onset schizophrenia is, however, associated with a need for lower neuroleptic dosages, milder cognitive impairment, and most interestingly, larger thalamic volume on MRI, compared to early-onset schizophrenia. We will discuss issues related to the neurodevelopmental versus neurodegenerative models of schizophrenia as well as possible factors that could be responsible for delaying the onset of schizophrenia until later in life.