To access (FAP) subjects will participate in: 10 therapy sessions; and the following treatments: 1) identify strategies with unique patterns of neural circuit maturation associated with early visceral pain on the gut-brain axis: 2) adapt acceptance-based behavioral strategies used to address psychopathology in older children to younger children; and 3) incorporate caregivers as role models and facilitators based on attachment research.

Investigator's ten session intervention trains children to be "Feeling and Body Investigators". Half of the sessions will be done in clinic and half at home via web-camera to facilitate generalization. During the treatment child/caregiver dyads will 1) gather body clues (Learn), 2) investigate (Experience: perform interoceptive mystery missions to explore a body sensation), 3) organize body clues (Contextualize: recall other context that evoke similar sensations), and 4) go on increasingly daring missions (Challenge: decrease avoidance and safety behaviors).

If successful, young children with FAP who complete the FBI early intervention will learn to experience changes in the viscera as fun and fascinating, rather than scary, and will develop new capacities for pain management, adaptive functioning, and emotion regulation.

Treatment in this study refers to 10 treatment sessions (2 over cell phone video chat from the subject's home and 8 in the investigator's lab) using an acceptance-based behavioral treatment for children 5 through 9 years old with impairing functional abdominal pain. This intervention is rooted in a biopsychosocial framework incorporating advances in neurodevelopment, behavioral learning theory, and attachment theory.

Enrollees will engage in assigned home-based practice sessions for at least nine of the ten treatment weeks. Completion of assigned practice sessions within a given week is defined as success.

Feeling and Body Investigators (FBI) is a 10-session intervention to treat children with functional abdominal pain. The treatment contains the following components: 1) We aim to reduce fearful perceptions of somatic and visceral sensations by linking sensations to playful characters. In sessions organized by theme (e.g., the Eats), children build curious reactions to things they notice in their bodies using funny cartoon characters used to teach them the meaning of different sensations (e.g. Betty Butterfly for gut butterflies of anxiety). 2) Children perform interoceptive exposure activities designed to demonstrate how smart and tough the body is in responding to different demands (e.g., seeing how fast a child can run even if they feel uncomfortable). 3) Children learn to link body sensations to meanings and actions. Using a Body Clues Worksheet, children figure out what they were feeling, what their feeling was telling them, and try out different ways to respond to the messages of their body to see what happens. 4) Families design investigations to help them face challenging situations (e.g. devising a plan to run around at recess to try to get all their gas out and see what happens to their abdominal pain after recess). If successful, kids with FAP who complete treatment will learn to experience body sensations as fun and fascinating, rather than scary, and develop new capacities for pain management, increase adaptive functioning, and enhance interoceptive responsivity.

Treatment in this study refers to 10 treatment sessions (2 over cell phone video chat from the subject's home and 8 in the investigator's lab) using an acceptance-based behavioral treatment for children 5 through 9 years old with impairing functional abdominal pain. This intervention is rooted in a biopsychosocial framework incorporating advances in neurodevelopment, behavioral learning theory, and attachment theory.

Feeling and Body Investigators (FBI) is a 10-session intervention to treat children with functional abdominal pain. The treatment contains the following components: 1) We aim to reduce fearful perceptions of somatic and visceral sensations by linking sensations to playful characters. In sessions organized by theme (e.g., the Eats), children build curious reactions to things they notice in their bodies using funny cartoon characters used to teach them the meaning of different sensations (e.g. Betty Butterfly for gut butterflies of anxiety). 2) Children perform interoceptive exposure activities designed to demonstrate how smart and tough the body is in responding to different demands (e.g., seeing how fast a child can run even if they feel uncomfortable). 3) Children learn to link body sensations to meanings and actions. Using a Body Clues Worksheet, children figure out what they were feeling, what their feeling was telling them, and try out different ways to respond to the messages of their body to see what happens. 4) Families design investigations to help them face challenging situations (e.g. devising a plan to run around at recess to try to get all their gas out and see what happens to their abdominal pain after recess). If successful, kids with FAP who complete treatment will learn to experience body sensations as fun and fascinating, rather than scary, and develop new capacities for pain management, increase adaptive functioning, and enhance interoceptive responsivity.