Altered voxel-based and surface-based morphometry in insomnia with short and normal objective sleep duration.

Objective Two subtypes of insomnia, classified by objective sleep duration, exhibit distinctly different clinical presentations. However, the brain morphological differences between subtypes remain poorly understood. This study aimed to compare the morphological differences between the objective short sleep duration (ISSD) and normal sleep duration (INSD) subtypes, using both voxel-based and surface-based morphometry analyses. We sought to determine whether morphological differences could serve as valid biomarkers to differentiate the subtypes.Method Forty ISSD and 39 INSD were included in the study. T1-weighted images were acquired. Both voxel-based and surface-based morphological metrics, including gray matter volume, cortical thickness, cortical gyrification, cortical complexity, and sulcus depth, were compared between the two subtypes. The identified structural differences were then used as features to train a support vector machine model to distinguish the two subtypes.Results No significant differences were found in cortical thickness, cortical gyrification, or cortical complexity between the ISSD and INSD subtypes. However, ISSD showed a significant reduction in gray matter volume in the bilateral putamen, while INSD exhibited a significant reduction in gray matter volume in the bilateral cerebellum. In terms of sulcus depth, the right superior temporal gyrus showed a significant reduction in ISSD when compared with INSD. Using the support vector machine, the model correctly classified the two subtypes with an accuracy of 76.9%, sensitivity of 70.2%, specificity of 83.8%, and an area under the curve of 0.835.Conclusions ISSD and INSD differ in specific brain morphological features, and these findings may provide preliminary discriminative information at the group level. (PsycInfo Database Record (c) 2026 APA, all rights reserved).