Stress refers to the perceived or actual threat on physical and/or psychological homeostasis of the human body. Disrupted homeostasis elicits the so called “stress response”, meaning the activation of central and peripheral neuroendocrine mechanisms responsible for various adaptive responses and behaviors. PSS was originally developed as a 14-item scale that assess the perception of stressful experiences by asking the respondent to rate the frequency of his/her feelings and thoughts related to events and situations that occurred over the previous month. Stress mainly refers to the perceived or actual threat to the physical and/or psychological homeostasis of the human body.