"Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS) is a condition that involves sudden, severe behavior and mood changes in children. Very quickly, sometimes overnight, they start to have obsessive-compulsive disorder (OCD) symptoms like urgent, unwanted thoughts. Or, they may abruptly avoid eating. Often, they develop tics, movements such as head turning or rapid blinking that they can't control." - Healthy Children AAP website.