Grey matter volume differences in pediatric obsessive-compulsive disorder: a meta-analysis of voxel-based morphometry studies.

Background: Obsessive-compulsive disorder (OCD) is one of the most commonly seen mental disorders onset from childhood. The neural mechanisms underlying OCD development and maintenance remain poorly understood. Various empirical evidence from structural magnetic resonance imaging (MRI) studies has reported structural differences in grey matter (GM) among pediatric OCD patients. However, some of the findings diverge from others, and the association between GM and individual differences in pediatric OCD remains inconclusive. To address this gap, we conducted a meta-analysis to synthesize findings quantitatively.

Methods: The current research conducted a quantitative meta-analysis of voxel-based GM studies to elucidate existence of neural correlates in pediatric OCD. A whole brain-based d-mapping approach was utilized to explore GM changes and further analyze the relationship between GM and individual differences in pediatric OCD patients.

Results: Thirteen studies were included with 288 patients and 273 controls. Compared with controls, pediatric OCD demonstrated significantly greater GM volume in the left insula (SDM value = 1.72, p < 0.005) and left superior frontal gyrus (SFG) (orbital part) (SDM value = 1.47, p < 0.005), whereas we showed lower GM volume in the right superior temporal gyrus (STG) (SDM value = -1.87, p < 0.005), left inferior parietal gyri (IPG) (SDM value = -1.60, p < 0.005), left middle occipital gyrus (MOG) (SDM value = -1.66, p < 0.005), and left inferior frontal gyrus (IFG) (SDM value = -1.69, p < 0.005). The increase in SFG (orbital part) and decrease IPG was commonly found in those without psychiatric comorbidities and treatment-naive subgroup. Meta-regression analysis revealed that longer OCD duration was associated with less GM volume in IPG (SDM value = -3.057, p < 0.005). Finally, the onset age and the OCD symptoms severity were positively associated with GM volume in the SFG (SDM z = 2.387, p < 0.005).

Conclusions: Our findings confirmed the most consistent GM differences in pediatric OCD, particularly in the MOG, IPG and SFG (orbital part), suggesting they are potential markers in pediatric OCD. Larger SFG (orbital part) and smaller IPG volumes are specific to those without comorbidities and untreated patients. The duration of OCD, symptom severity and onset age also influence GM structure. This research provides evidence of the underlying neuroanatomical characteristics of pediatric OCD.

Trial Registration: PROSPERO CRD42024601906.