“All of the effort expended in the destructive cycles of PTSD wreaks psychological and physiological havoc. People with PTSD try to compensate for this hyperarousal by shutting down and withdrawing from any kind of stimulation. They use dissociation and a range of mood-altering behaviors—cutting and burning, bingeing and purging, drinking and drugs, sex and starvation—to numb out and regulate their emotions and keep the intrusive memories at bay. Over time, however, they become so numb and withdrawn that "this underresponsiveness leads to a series of changes in the nervous system that are similar to the effects of prolonged sensory deprivation," says van der Kolk.”