Any instance of time in which the feeling of utter loneliness begins eating at either one's mind, one's heart, or both. Can be diagnosed as soon as felt taking effect, but not before. Can be very detrimental to one's life and body, as the feeling of utter loneliness can wreak havoc on one's psyche.
The best course of treatment is to go out of doors and socialize with friends and/or family. Perhaps going out to eat, or going out to a local sports event.