Hilal Melis ALTINTAŞ, İbrahim POYRAZ, Zeyad KAMAR, Ali KÖKSAL, Berin TUĞTAĞ DEMİR, Burak BİLECENOĞLU
Uludağ Üniversitesi Tıp Fakültesi Dergisi - 2026;52(1):1881027-0
Cavum septum pellucidum (CSP), cavum vergae (CV), cavum veli interpositi (CVI), and interthalamic adhesion (IA) are midline developmental variants and their associations with psychiatric disorders are unclear. Our study aimed to compare the prevalence of these four structures and the dimensional features of CSP in bipolar disorder (BD), major depression (MD), and obsessive-compulsive disorder (OCD) with healthy controls (HC) under a single MRI protocol. A total of 454 adults with 1.5T brain MRI were examined retrospectively. CSP length <=6 mm was classified as "small," >6 mm as "large"; the presence of CV, CVI, and IA was evaluated by two blinded radiologists. When all participants (patients and healthy controls) were considered together, CSP prevalence was 61.5%. "Large" CSP was observed only in clinical groups (BD 23.8%; MD 38.1%; OCD 38.1%). CVI was found in 37.4% of OCD and 29.9% of MD patients, showing a significant increase compared to 10.5% in HC (p<0.001). CV prevalence was 16.3% in HC; 35.6% in OCD; 28.8% in MD (p<0.001). Absence of IA was found in 64.6% of patients and 35.4% of HC, revealing an intergroup difference (p<0.05). In BD, MD, and especially OCD, the prevalence of CSP, CV, and CVI, along with IA absence, was significantly increased compared to HC. The findings suggest that these variants are not limited to psychotic disorders and may have neurodevelopmental biomarker potential across a broader mood/anxiety spectrum, emphasizing the need for prospective validation studies.
