Responses to voluntary hyperventilation in children with separation anxiety disorder: implications for the link to panic disorder

Abstract

Background: Biological theories on respiratory regulation have linked separation anxiety disorder (SAD) to panic disorder (PD). We tested if SAD children show similarly increased anxious and psychophysiological responding to voluntary hyperventilation and compromised recovery thereafter as has been observed in PD patients.

Methods: Participants were 49 children (5-14 years old) with SAD, 21 clinical controls with other anxiety disorders, and 39 healthy controls. We assessed cardiac sympathetic and parasympathetic, respiratory (including pCO2), electrodermal, electromyographic, and self-report variables during baseline, paced hyperventilation, and recovery.

Results: SAD children did not react with increased anxiety or panic symptoms and did not show signs of slowed recovery. However, during hyperventilation they exhibited elevated reactivity in respiratory variability, heart rate, and musculus corrugator supercilii activity indicating difficulty with respiratory regulation.

Conclusions: Reactions to hyperventilation are much less pronounced in children with SAD than in PD patients. SAD children showed voluntary breathing regulation deficits.

Keywords: AX; CC; Childhood anxiety; ECG; EMG; ET; HC; HF; HR; IBI; ICG; MAP; NSFn; PD; PEP; Psychophysiology; RL; RMSSD; RR; RSA; SAD; SCL; Separation anxiety disorder; TPR; VH; Vmin; Voluntary hyperventilation; Vt; VtV; anxiety; arterial partial pressure of carbon dioxide; clinical controls; electrocardiogram; electromyography; end task; healthy controls; heart rate; high frequency range of heart period variability; impedance cardiography; interbeat intervals; mean arterial pressure; minute ventilation; non-specific skin conductance fluctuations; pCO(2); panic disorder; preejection period; respiratory rate; respiratory sinus arrhythmia; restlessness; root mean squared successive breath-by-breath differences of tidal volume; root mean squared successive difference; separation anxiety disorder; skin conductance level; tidal volume; total peripheral resistance; voluntary hyperventilation.