In the absence of evidence-based treatments for RD, the investigators, alongside a collaboration with Dr. Jennifer Thomas at the Eating Disorders Clinical and Research Program (EDCRP) at Massachusetts General Hospital, have created a manualized treatment, Cognitive-Behavioral Therapy for Rumination Disorder (CBT-RD) informed by published case reports and currently in use at EDCRP at Massachusetts General Hospital and the Psychological Services Center at Drexel University. CBT-RD targets the habitual contraction of the abdominal wall and preceding events through the use of habit reversal, using primarily diaphragmatic breathing as a competing response.