The National Stressful Events Survey PTSD Short Scale (NSESSS) is a 9-item measure that assesses the severity of posttraumatic stress disorder in individuals age 18 and older following an extremely stressful event or experience. The measure was designed to be completed by an individual upon receiving a diagnosis of posttraumatic stress disorder (or clinically significant posttraumatic stress disorder symptoms) and thereafter, prior to follow-up visits with the clinician. Each item asks the individual receiving care to rate the severity of his or her posttraumatic stress disorder during the past 7 days.