Cavum septum pellucidum in monozygotic twins discordant for combat exposure: relationship to posttraumatic stress disorder

May FS, Chen QC, Gilbertson MW, Shenton ME, Pitman RK

Biol. Psychiatry 2004 Mar;55(6):656-8

PMID: 15013837


BACKGROUND: Abnormally large cavum septum pellucidum has been reported in posttraumatic stress disorder; however, the origin of this association is uncertain.

METHODS: We utilized magnetic resonance imaging to measure cavum septum pellucidum in pairs of identical twins discordant for combat exposure in Vietnam.

RESULTS: Presence of abnormal cavum septum pellucidum was significantly correlated between exposed and unexposed twins, indicating that it is partially determined by heredity and/or shared environment. There was a greater proportion of cavum septum pellucidum in combat-exposed twins with posttraumatic stress disorder and their noncombat-exposed co-twins.

CONCLUSIONS: The presence of abnormally large cavum septum pellucidum is a familial vulnerability factor for posttraumatic stress disorder.