Schizophrenia as a disorder of developmentally reduced synaptic connectivity.

Recent postmortem and neuroimaging studies of schizophrenia delineate changes in brain structure and volume that appear to arise from a reduction of neuritic processes (such as dendrites and synapses) rather than loss of neuronal or glial cell bodies. To account for these findings, we propose a pathophysiological model of reduced synaptic connectivity arising from disturbances of brain development active during perinatal and adolescent periods. We review a computer simulation of the elimination of the synaptic connections that models normal cognitive development and psychotic symptom formation. We describe the model's key parameters and discuss how they can account for important aspects of schizophrenia, including its unique symptoms, short- and long-term course, typical age of onset, neurodevelopmental deficits, limited neurodegenerative progression, sex differences, and more. We discuss some of the model's predictions and questions raised for basic research, early detection, and preventive intervention.