Hyperostosis frontalis interna and mental morbidity.

Forty-six mentally ill women with radiologically verified hyperostosis frontalis interna (HFI) were compared with 46 matched mentally ill women without HFI in respect of mental morbidity among the full siblings of the two groups. It was found that mental morbidity was lower among the siblings on mentally ill women with HFI than among those of similar mentally ill women without HFI. A reasonable interpretation of these findings is that the combination mental illness-HFI is more often exogenously determined than other forms of mental illness.