Reduced posterior nasal cavity volume: a gender-specific neurodevelopmental abnormality in schizophrenia.

OBJECTIVE: We previously reported that men with schizophrenia had reduced volumes of the posterior nasal cavity bilaterally. Since the nasal cavities develop in conjunction with both the palate and ventral forebrain, this could represent a simple marker of embryological dysmorphogenesis contributing to schizophrenia. The current study expands on this finding by examining a larger sample of both male and female patients and unaffected 1st-degree relatives, to determine the gender distribution of this abnormality and the extent to which it may be genetically mediated.
METHOD: A measurement of nasal volume and geometry was acquired by acoustic rhinometry for 85 schizophrenia patients, 25 unaffected 1st-degree relatives of schizophrenia probands and 66 healthy comparison subjects.
RESULTS: Male patients had smaller posterior nasal volumes than both male control subjects and male relatives. However, female patients did not differ from either female controls or female family members. Unaffected 1st-degree relatives did not differ from same-sex control subjects. These findings persisted after covarying for height and smoking history, and were unrelated to clinical symptomatology or antipsychotic medication usage.
CONCLUSION: Posterior nasal cavity volume decrement appears to be a specific developmental craniofacial abnormality that may reflect an early disruption in embryological development in males with schizophrenia. Although further study is needed, this may be a marker of a "second hit" that distinguishes genetically vulnerable men who go on to develop the illness from those who do not.