Decreased number of orbital sulci in schizophrenia spectrum disorders

•This MRI study examined the number of orbital sulci in the schizophrenia-spectrum.•Schizophrenia and schizotypal patients had a decreased number of orbital sulci.•Sulcus number was related to the severity of negative symptoms.

An altered orbitofrontal sulcogyral pattern has been reported in the schizophrenia-spectrum, but it remains unknown whether they also have differences in the number of intermediate and posterior orbital sulci compared with healthy subjects. This magnetic resonance imaging study investigated the number of these sulci in 102 schizophrenia patients, 47 schizotypal disorder patients, and 84 controls. Both patient groups had a significantly lower number of both sulci bilaterally compared with controls, which was weakly associated with the severity of negative symptoms. Our results may reflect the neurodevelopmental pathology related to vulnerability to psychosis.