Generalized anxiety disorder, comorbid major depression and heart rate variability: a case-control study in taiwan.
OBJECTIVE
Decreased heart rate variability (HRV) has been reported in generalized anxiety disorder (GAD), but the results are mixed. Little is known about the impact of comorbid major depression (MD) on HRV in GAD patients. Both issues necessitate further investigation.


METHODS
Twenty unmedicated, physically healthy GAD patients, 20 GAD patients with a secondary diagnosis of MD, 40 MD patients and 60 matched controls were recruited. We used the Hamilton Anxiety Rating Scale and the Hamilton Depression Rating Scale to assess anxiety and depression severity, respectively. Cardiac autonomic function was evaluated by measuring HRV parameters. Frequency-domain indices of HRV were obtained.


RESULTS
Three patient groups had more anxiety and depression symptoms than control subjects, but heart rates (HRs) were significantly elevated only in GAD patients with comorbid depression. Relative to controls, GAD patients had reduced HRV while GAD patients with comorbid depression displayed the greatest reductions in HRV among three patients groups. Correlation analyses revealed anxiety/depression severity significantly associated with HRs, variance, LF-HRV and HF-HRV. However, separately analyzing among individual groups and adjusting for HRV-associated covariables rendered the correlations non-significant.


CONCLUSIONS
Our results suggest that reduction in HRV is a psychophysiological marker of GAD and individuals with comorbid GAD and MD may be distinguished based on psychophysiological correlates (for example, HF-HRV) from non-comorbid GAD patients. Taken into account that comorbid depression may confer increased risks for cardiovascular events in GAD patients, this subgroup of GAD patients may benefit better from cardiovascular risk reduction strategies.
Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Hsin-An
HA
Chang
Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Chuan-Chia
CC
Chang
Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. ; Student Counseling Center, National Defense Medical Center, Taipei, Taiwan.
Nian-Sheng
NS
Tzeng
Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.
Terry B J
TB
Kuo
Institute of Behavioral Medicine and Department of Psychiatry, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Ru-Band
RB
Lu
Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
San-Yuan
SY
Huang
Cardiac autonomic function; Generalized anxiety disorder; Heart rate variability; Major depression; Vagal control