Respiratory perception measured by cortical neural activations in individuals with generalized anxiety disorder.

There has been evidence for the effect of anxiety on the neural processing of respiratory sensation using the respiratory-related evoked potentials (RREP) elicited by inspiratory occlusions. This study tested the RREP elicited by inspiratory occlusions in a group of outpatients with generalized anxiety disorder (GAD) and a group of healthy controls. We hypothesized that the RREP P3 peak would be modulated in the GAD patients. A RREP oddball paradigm of 150-ms inspiratory occlusion protocol was used in 15 GAD patients and 11 healthy adults with normal lung functions. The RREP was recorded with a 40-channel electroencephalography (EEG) system. A minimum of 100 occlusions was collected for data analysis. We found that the averaged P3 latency of the GAD patients was significantly longer than the P3 latency of the healthy controls. In addition, the GAD group showed significantly reduced P3 amplitudes compared to the control group. No group differences in latency and amplitudes were found for earlier RREP components. These results demonstrated that a delayed and reduced attention peak (P3) is present in patients with GAD. This suggests that GAD as a disease state modulates the higher order processing of respiratory perception.