Gender differences in gray matter volume of the anterior cingulate cortex and suicidal ideation in patients with major depressive disorder: evidence from the REST-meta-MDD project

Patients with major depressive disorder (MDD) have gender differences in many aspects, including suicidal ideation (SI) and grey matter volume (GMV). The relationship between GMV of the anterior cingulate cortex (ACC) and SI in patients with MDD is unknown, especially whether there is gender difference in this relationship. The purpose of this study was to explore gender differences in SI, GMV of the ACC and their relationship in patients with MDD in China, which has not been reported yet. As part of the REST-meta-MDD consortium, 246 patients with MDD and 235 healthy controls were recruited, including 123 MDD patients with SI and 123 MDD patients without SI. All participants underwent magnetic resonance imaging (MRI) brain scans. The 17-item Hamilton Depression Rating Scale (HAMD) was used to assess depressive symptoms. Male MDD patients with SI had a longer disease duration than female patients with SI, whereas male MDD patients without SI had a lower rate of medication use than female MDD patients without SI (all p < 0.05). HAMD was significantly higher only in male MDD patients with SI than in male MDD patients without SI (p < 0.01). In the male SI group, the GMV of the right ACC was greater than in the female SI group, and in female MDD patients only, the GMV of the bilateral ACC was significantly greater in the SI group than in the non-SI group (all p < 0.001). In both male and female MDD patients, SI was positively correlated with HAMD, whereas in female MDD patients, SI was positively correlated with GMV of the ACC, which was confirmed in the subsequent regression equation. Our findings suggest that there are gender differences in SI, GMV of the ACC, and the association between them in patients with MDD.