Differences in brain functioning between obsessive-compulsive disorder and generalized anxiety disorder: a clinical...

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Generalized anxiety disorder (GAD) and obsessive-compulsive disorder (OCD) share clinical and epidemiological traits, yet their neurobiological underpinnings are not fully understood.
• Investigating brain function differences and similarities between GAD and OCD is crucial for understanding these related disorders.

Purpose of the Study:

• To compare brain activity patterns between GAD patients, OCD patients, and healthy controls (HCs) using functional near-infrared spectroscopy (fNIRS).
• To identify specific neurobiological differences and similarities in brain functioning between GAD and OCD.

Main Methods:

• A 53-channel fNIRS system measured oxygenated hemoglobin ([oxy-Hb]) changes during a verbal fluency task in 31 GAD patients, 31 OCD patients, and 31 HCs.
• Analysis focused on five regions of interest: premotor cortex/SMA, Broca's area, DLPFC, FEF, and FPA.
• Statistical comparisons included one-way ANOVA, post-hoc tests, correlation analysis, and ROC curve analysis.

Main Results:

• HCs demonstrated significantly higher brain activation in the DLPFC, PFC, and Broca's area compared to both GAD and OCD patients.
• GAD patients showed greater activation in the left DLPFC and left FPA than OCD patients.
• Right FPA [oxy-Hb] values effectively distinguished patient groups from HCs (AUC = 0.769).

Conclusions:

• While GAD and OCD share some neurofunctional alterations, OCD patients exhibit more pronounced deficits in the left DLPFC and left FPA.
• fNIRS can identify distinct patterns of brain activation differentiating GAD and OCD from healthy individuals.
• Obsessive-compulsive symptoms were negatively correlated with activation in the left Broca's area.