Recent findings have strengthened the hypothesis that a dysfunction of neuronal synapses and dendrites is relevant for the pathogenesis of schizophrenia. It might be present during neurodevelopment as well as in degenerative and regenerative processes of the mature brain. S1OOB, a small, Ca2+-binding, astrocytic protein, plays an important role in modulating the proliferation and differentiation of neurons and glia cells. It is involved in the regulation of cellular energy metabolism and interacts with many immunological functions of the brain. This review addresses findings from cell cultural and animal experiments potentially pertinent for the pathogenesis of schizophrenic psychoses. Morphological and functional data are analyzed and clinical studies reporting alterations of S1OOB concentrations in schizophrenic patients are reviewed. Evidence and limitations of the available studies are pointed out and promising future research strategies are outlined.