**7. Conclusions**

The present chapter described the different profiles of HRV found in MDD and GAD, and tried to delineate the functional significance of the findings in terms of autonomic activity. It is interesting to use HF and LF indices to evaluate the pathophysiology of mental disorders based on the physiological mechanisms underlying HRV.

Although depression and anxiety coexist frequently, the patterns of autonomic dysregulation show differences when viewed from HRV analyses. Depression is mainly accompanied by parasympathetic inhibition and unresponsiveness. In anxiety, augmentation of parasympathetic activity is present during the condition when the symptoms are controlled. When phobic symptoms appear, parasympathetic activity lowers and the autonomic balance is lost. Then the autonomic dysregulation in anxiety becomes similar to that of depression.

It should be important to understand the differences and similarities to evaluate the pathophysiology of depression and anxiety in clinical practices. Differentiation of depressive and anxious conditions using HRV measures can be useful for adequate pharmacological, psychological, and behavioral therapies [14].
