Depth of the olfactory sulcus: a marker of early embryonic disruption in schizophrenia?

Embryonic insults during early gestation increase the risk of schizophrenia. Abnormal forebrain development during this period is often characterized by a shallow olfactory sulcus. The adjacent orbital sulcus does not develop until the third trimester and so is immune to early intrauterine insults. We measured olfactory and orbital sulcal depths in 36 patients and 28 control subjects. Patients had shallower olfactory sulci, but normal orbital sulci. Olfactory and orbital sulcal depths were correlated in controls, but not in patients. Olfactory sulcal depth may therefore be a biomarker denoting an early embryonic disruption in individuals at risk for schizophrenia.