Functional abdominal pain disorders (FAPDs), now called disorders of gut-brain interaction (DGBIs), are among the most common conditions seen by pediatric gastroenterologists. They affect approximately one in four children worldwide. These conditions cause real, often significant pain, but tests don't reveal structural abnormalities or disease.
The term "functional" doesn't mean the pain isn't real or is "all in their head." Rather, it reflects that these conditions arise from how the gut and brain communicate, not from damage or disease. The pain is genuine, and so is the impact on your child's life.
Types of functional abdominal pain disorders include:
Does your child have recurring stomachaches, especially around the belly button?
Do stress, like tests, social situations, or transitions, seem to trigger or worsen their stomach symptoms?
Has your child had extensive testing that "comes back normal" even though the pain is real?
Do they experience bloating, gas, constipation, or diarrhea alongside their pain?
Does your child also struggle with anxiety, worry, or low mood?
Have they had repeated infections or courses of antibiotics?
Does your child have ADHD, autism, or other neurodevelopmental differences?
Do certain foods seem to make symptoms worse?
Is your child missing school or avoiding activities because of stomach problems?
Do they have skin issues like eczema or allergies alongside their GI symptoms?
The enteric nervous system (ENS), sometimes called the "second brain," consists of more than 100 million nerve cells lining the gastrointestinal tract. These nerve cells constantly communicate with the brain and vice versa. Think of it as constant "static noise" traveling between gut and brain. When stress is added to the mix, that static becomes much louder.
The gut-brain axis works through several pathways:
This communication is bidirectional. Just as stress and anxiety can cause stomach symptoms, gut problems can trigger or worsen anxiety and mood issues. Research shows that both brain-to-gut and gut-to-brain pathways operate in IBS and other functional GI disorders.
The connection between gut disorders and mental health in children is striking. A large study found that children with disorders of gut-brain interaction had significantly higher rates of anxiety (40.3%) and depression (33.6%) compared to children without these conditions (16.7% and 12.0%, respectively). More frequent and intense abdominal pain was associated with higher anxiety levels, and each additional daily episode of diarrhea dramatically increased anxiety risk.
This isn't a coincidence, it's biology. Chronic abdominal pain can contribute to mood problems through neural sensitization (where the brain becomes more sensitive to pain signals), activation of the stress response, and impaired social functioning due to missed school and social withdrawal. Children with functional GI disorders often develop other gut-brain conditions as they grow.
Your child's gut is home to trillions of microorganisms (bacteria, fungi, and other microbes) whose collective genes make up the gut microbiome. These microbes aren't just passengers; they actively influence health and behavior.
Gut bacteria produce neurotransmitters that affect mood and cognition. Different bacterial species produce different neurotransmitters: Lactobacillus species produce acetylcholine and GABA, Bifidobacterium species produce GABA, Bacillus species produce norepinephrine and dopamine, and various bacteria produce serotonin. Gut microbiota also influence the availability of tryptophan, the amino acid precursor to serotonin, which can cross the blood-brain barrier and affect serotonin synthesis in the brain.
When the gut microbiome becomes imbalanced (dysbiosis), problems can follow. Research has found characteristic microbiome differences in children with ADHD, autism, anxiety, and depression. Children with ADHD tend to have decreased Faecalibacterium (which produces anti-inflammatory short-chain fatty acids) and alterations in bacteria involved in dopamine production. Studies have even shown that transplanting gut microbiota from individuals with ADHD into mice can alter the mice's brain function and behavior.
The intestinal wall is just one cell thick (the same thickness as your eyelids) but it serves as a crucial barrier. Tight junctions between cells act like mortar between bricks, allowing nutrients through while keeping out harmful substances.
When this barrier becomes damaged or "leaky," undigested food particles, bacteria, and toxins can pass into the bloodstream, triggering immune responses and inflammation. This increased intestinal permeability has been found in children with functional GI disorders and is associated with conditions ranging from food sensitivities to eczema to behavioral issues.
Factors that can contribute to increased intestinal permeability include dysbiosis, certain dietary factors (like excessive FODMAPs, or fermentable sugars), chronic stress, infections, and some medications. Research shows that probiotic treatment, particularly with Lactobacillus rhamnosus GG, can improve intestinal permeability in children.
ADHD: The microbiome-gut-brain axis is increasingly recognized as playing a role in ADHD. Studies have found differences in gut microbiome composition between children with and without ADHD. Hyperactivity and impulsivity have been negatively correlated with Faecalibacterium (a beneficial bacteria) and positively correlated with Bacteroides species. Because gut bacteria influence dopamine and serotonin neurotransmitters central to ADHD, the gut microbiome represents a potential therapeutic target.
Autism Spectrum Disorder: Children with autism have high rates of GI symptoms constipation, diarrhea, and abdominal pain are common. Research has found that children with autism have significantly decreased levels of certain gut-derived metabolites, including those related to tryptophan metabolism. Probiotic treatments and dietary interventions that improve gut health have shown promise in reducing both GI symptoms and some behavioral symptoms in children with autism.
Because functional abdominal pain disorders arise from gut-brain interaction, effective treatment often addresses both sides of the equation. Available pharmacological interventions are limited in children, so management has focused on combined approaches:
Mind-Targeted Interventions: Psychological interventions have strong evidence for functional abdominal pain disorders. Cognitive behavioral therapy (CBT) helps children understand the gut-brain connection and develop coping strategies. Gut-directed hypnotherapy has proven particularly effective, reducing symptoms, disability, and improving quality of life. These approaches work by downregulating the stress response and changing how the brain processes gut signals.
Dietary Modifications: Keeping a food journal can help identify trigger foods. Some children with IBS respond well to a low-FODMAP diet (reducing poorly digested sugars). Adequate fiber intake, particularly soluble, fermentable fiber, supports a healthy microbiome and produces beneficial short-chain fatty acids. A Mediterranean-style diet rich in fruits, vegetables, whole grains, and omega-3 fatty acids supports both gut and brain health.
Microbiome Support: Probiotics can help restore microbial balance. Lactobacillus rhamnosus GG is the most studied probiotic in pediatric functional GI disorders, with research showing reduced pain intensity and frequency compared to placebo, as well as improved intestinal permeability. Prebiotics (foods that feed beneficial bacteria) and a diverse, whole-foods diet support a healthy microbiome.
Other Approaches: Peppermint oil has antispasmodic effects and may help with intestinal cramping. Yoga and breathing techniques can help downregulate the stress response. Some specialized centers offer percutaneous electrical nerve field stimulation or auricular acupuncture for refractory cases.
At Cedars Functional Medicine, we recognize that gut-brain symptoms are real, not imaginary, and that they require a comprehensive approach:
Thorough Evaluation: We take time to understand your child's full history, GI symptoms, mental health, development, diet, and any patterns you've noticed. We rule out red flags that warrant further investigation while avoiding unnecessary invasive testing.
Education and Validation: Understanding the gut-brain connection is itself therapeutic. When children and parents understand that these symptoms have a biological basis, that stress hormones really do affect the gut, that gut bacteria really do produce brain chemicals, it reduces fear and empowers families.
Laboratory Assessment: When appropriate, we may evaluate nutritional status, inflammatory markers, food sensitivities, or stool testing to identify modifiable factors contributing to symptoms.
Nutritional Guidance: We help identify trigger foods and develop an eating pattern that supports gut and brain health without being overly restrictive.
Coordination with Mental Health Providers: Because gut-brain symptoms often co-occur with anxiety, we collaborate with therapists who specialize in pediatric anxiety and can provide CBT or hypnotherapy when appropriate.
Referral When Needed: Children with red flag symptoms, symptoms that don't respond to initial management, or complex presentations may need evaluation by a pediatric gastroenterologist.
Your child's safety comes first. Seek prompt evaluation if your child has any of these red flag symptoms:
These symptoms may indicate conditions that require different evaluation and treatment. Functional abdominal pain disorders are diagnosed only after an appropriate evaluation rules out other causes.
Absolutely. Functional abdominal pain is not "made up" or "all in their head." Research shows that children with these conditions have visceral hypersensitivity—their gut and brain are more sensitive to normal gut sensations, experiencing them as painful. Brain imaging studies confirm altered connectivity patterns in youth with functional GI disorders. The pain is real; it's the cause that differs from structural diseases.
Both. Research has confirmed that independent gut-to-brain and brain-to-gut pathways operate in functional GI disorders. Anxiety can trigger or worsen gut symptoms through stress hormones and altered gut motility. At the same time, chronic gut inflammation and pain can affect brain chemistry and trigger anxiety. This is why effective treatment often needs to address both.
Many children do improve with time and appropriate management. However, untreated functional GI disorders can persist and evolve. Children with childhood functional abdominal pain have a significantly increased risk (2.3 times higher) of anxiety disorders in adulthood. This is why early intervention—including psychological therapies—is important not just for current symptoms but for long-term outcomes.
Probiotics can be helpful for some children with gut-brain symptoms. Lactobacillus rhamnosus GG has the most research support in pediatric functional GI disorders. However, probiotics work best as part of a comprehensive approach that includes dietary changes and stress management—not as a standalone solution. Different strains have different effects, so it's worth discussing with a healthcare provider which might be appropriate for your child.
They may be. Research increasingly links ADHD to gut microbiome differences. Children with ADHD have higher rates of GI symptoms than their peers, and gut bacteria influence the same neurotransmitters (dopamine, serotonin) implicated in ADHD. Addressing gut health may complement other ADHD treatments, though more research is needed.
Gut-directed hypnotherapy is a specialized technique where a trained therapist guides your child into a relaxed state and uses suggestions to change how the brain processes gut sensations. It's not mind control or stage hypnosis—it's an evidence-based treatment with strong research support for pediatric functional GI disorders. It's safe, non-invasive, and has lasting benefits that persist after treatment ends.
Keeping a food diary to identify triggers can be helpful. Some children benefit from reducing FODMAPs (fermentable sugars found in certain fruits, vegetables, and grains). However, overly restrictive diets can be harmful for growing children and may worsen nutritional status. Any significant dietary changes should be guided by a healthcare provider or dietitian to ensure adequate nutrition.
Possibly. Antibiotics can significantly disrupt the gut microbiome, and the timing of this disruption—particularly in early life—seems to be important for gut-brain development. Post-antibiotic dysbiosis can contribute to functional GI symptoms. Probiotic supplementation during and after antibiotic courses may help restore balance.
Stress doesn't "cause" functional GI disorders in a simple way, but it's an important factor. Stressful events—like moves, family changes, or school pressures—are associated with these conditions. The gut-brain connection means that stress hormones directly affect gut function. Learning stress management techniques is an important part of treatment.
Yes. Initial evaluation, education, dietary guidance, and coordination of care can all be done via telehealth. If specialized testing or in-person evaluation by a gastroenterologist is needed, we can help facilitate those referrals.
You may also want to read about Anxiety, Worry & Panic in Kids, ADHD & Focus Issues, Autism Spectrum Support, Food Sensitivities & Nutrient Deficiencies, since these areas often overlap with gut-brain symptoms.
Medically Reviewed By: Dr. Juliana Nahas, MD, FAAP, FMACP
ADD/ADHD
Conduct & Oppositional Disorders
Anxiety, Worry & Panic in Kids
Autism Spectrum Support
PANDAS / PANS
Immune-Triggered Neuropsychiatric Symptoms
OCD, Intrusive Thoughts & Compulsions
Mood Dysregulation
Depression
Sleep Issues & Fatigue in Children
Gut-Brain Symptoms
Food Sensitivities & Nutrient Deficiencies
Dr. Nahas’s private practice is 100% virtual and serves patients across the entire state of Florida. While the practice is registered in St. Petersburg, care is delivered remotely, allowing access to individuals and families throughout Florida without geographic restriction.