An observational study on gray matter volume and white matter integrity in suicide attempters with bipolar I disorder

Bipolar disorder (BD) is associated with a high risk of lifetime suicide attempts, but relatively few neuroimaging studies have investigated suicidality in the context of BD.

The study aimed to assess the white matter (WM) integrity and gray matter (GM) volume associated with suicide attempts in BD.

This observational study recruited 32 patients with DSM-5 bipolar I disorder. Group I had multiple (≥2) lifetime suicide attempts, with at least one attempt in the past year. Group II comprised nonattempters/nonideators who screened negative on the C-SSRS-lifetime version. All patients were euthymic (≤8 on 17-item HAM-D; ≤4 on YMRS). Study assessments included a clinical proforma, NIMH-Life Chart Method, and Barratt's Impulsivity Scale (BIS). MR imaging was performed using a 32-channel head coil on a 3T-MR scanner. All participants underwent DTI, and images were processed using tract-based spatial statistics (TBSS).

The study groups were comparable for age, gender, total BIS, and illness variables. The mean age was 34.3 years (SD 10.4), with 62.5% males in group I. Group comparisons for FA value revealed a lower WM anisotropy for five clusters (threshold of FA 0.2; P < 0.001; GRF corrected) in the suicide attempters' group. These included the left and right inferior fronto-occipital fasciculus (IFOF), left superior longitudinal fasciculus (SLF), cingulate, and forceps minor. Voxel-wise analysis of GMV did not show any significant group differences.

The findings indicate white matter disruptions associated with lifetime suicide attempts in BD, particularly in the bilateral IFOF, left SLF, cingulate, and forceps minor.