Cognitive Behavioral Therapy for Functional Dyspepsia (Epigastric Pain Syndrome and Postprandial Distress Syndrome Subtypes)

The goal of this clinical trial is to learn whether adding Cognitive Behavioral Therapy (CBT) to standard medical treatment can improve symptoms in adults with Functional Dyspepsia. The study includes adults aged 18 to 65 years diagnosed with Functional Dyspepsia, classified as Epigastric Pain Syndrome or Postprandial Distress Syndrome. The main questions it aims to answer are: Does Cognitive Behavioral Therapy added to standard treatment reduce gastrointestinal symptoms compared with standard treatment alone? Do patients with Postprandial Distress Syndrome and Epigastric Pain Syndrome respond differently to Cognitive Behavioral Therapy? Researchers will compare optimized standard medical treatment alone to optimized standard treatment combined with Cognitive Behavioral Therapy to see if the addition of CBT leads to greater symptom improvement and better quality of life. Participants will: Be randomly assigned to receive either standard medical treatment alone or standard treatment plus Cognitive Behavioral Therapy Take part in clinical visits and complete questionnaires about gastrointestinal symptoms, psychological well-being, and quality of life Provide blood, saliva, and stool samples at several time points over a 12-month follow-up period