Some authors have conceptualized depression as a "depletion syndrome" because of the prominence of fatigability; they postulate that the patient exhausts his available energy during the period prior to the onset of the depression and that the depressed state represents a kind of hibernation, during which the patient gradually builds up a new story of energy.
There are three layers to the universe. In the lower, Tai Ching, and the middle, Shan Ching, the hindrance of a physical bodily existence is required. Those who fail to live consistently in accord with the Tao reside here. In the upper, Yu Ching, there is only Tao: the bondage of form is broken, and the only thing existing is the exquisite energy dance of the immortal divine beings.
The outward freedom that we shall attain will only be in exact proportion to the inward freedom to which we may have grown at a given moment. And if this is a correct view of freedom, our chief energy must be concentrated on achieving reform from within.