IBS is a functional disorder. This means that you have real symptoms, but there’s no physical changes or significant inflammation in your bowels (gut). The bowels may work differently in people with IBS, but the inside of the intestines is often normal. It’s not entirely clear what causes the symptoms. But in people with IBS, there may be an issue with how the intestines move.
IBS is a very common condition, but many people don’t know they have it. In the U.S., 15% of adults have symptoms of IBS. Only half of these people have an actual diagnosis of IBS.
Experts don’t know the exact cause of IBS. But there are some theories about why people may develop symptoms of IBS. These include:
The brain-gut connection: There’s evidence of two-way communication between the brain and the gut. In IBS, signals from the brain — like stress — can have a big effect on how the gut functions. On the other hand, signals from the gut can also trigger changes in your mood and how your brain functions.
The gut microbiome: There’s normally a balance between healthy and harmful bacteria in your gut. If the balance of bacteria in your gut is off, it can lead to IBS symptoms. This can happen after an infection like food poisoning.
Stress: Stressful events and traumatic experiences may play a role in the development of IBS. This could be due to chemical changes in the brain in response to trauma. This may affect the way the gut moves and your pain awareness.
There are also other medical conditions that may be linked to IBS. IBS occurs more often in people with these conditions:
Depression
Anxiety
Food intolerance or sensitivity
These conditions don’t actually cause IBS, and IBS won’t cause these conditions. But these conditions and IBS are commonly seen together.
Most people with IBS experience abdominal pain and changes in their bowel movements, like diarrhea, constipation, or both.
If you have IBS, you may also experience other symptoms, including:
Bloating
Gas
Mucus in your stool
Stomach cramps
Feeling of fullness after eating
But every person with IBS experiences their symptoms in a different way. You might have very different symptoms than someone else with IBS. And your own symptoms might be different with each IBS flare. The severity of the symptoms may also vary from person to person and with each IBS flare.
IBS can mimic other medical conditions — like inflammatory bowel disease (IBD), food intolerance, or colon cancer. To make sure you don’t have one of these other conditions, you’ll need tests like:
Stool studies
Labs (like iron levels, complete blood count, and food allergy testing)
If these tests don’t show signs of these other medical conditions, then your provider can diagnose you with IBS.
There are several different types of IBS. Your treatment plan will depend on which IBS subtype you have. So once you have an IBS diagnosis, your healthcare provider will ask you to complete expert-designed questionnaires to figure out your IBS subtype.
IBS subtypes include:
IBS-C (constipation): People with this subtype have a lot of constipation.
IBS-D (diarrhea): People with this subtype have a lot of diarrhea or loose stools.
IBS-M (mixed): People with this subtype can have hard stools that alternate with loose, watery stools.
IBS-U (unclassified): People with this subtype don’t have a consistent pattern to their stool changes.
These questionnaires ask about your pain experience over time. They also ask about how often you have pain with your bowel movements and how often you experience changes in the frequency and texture of your stool.
There are many different types of IBS treatments. They may include dietary and lifestyle changes as well as medications.
Treatment plans aim to improve symptoms and depend on your IBS subtype. Just as IBS symptoms can be different for each person, the treatments will differ too.
Different foods can trigger IBS flares. You can reduce IBS flares and improve your symptoms by avoiding triggers. Some dietary changes that can improve IBS include:
Eating more fiber
Avoiding gluten-rich foods
Eating more low-FODMAP foods (like nuts, strawberries, spinach, and eggs)
Eating fewer high-FODMAPs foods (like dairy, beans, apples, and onions)
Avoiding common food triggers (like spicy foods and fatty foods)
Avoiding common beverage triggers (like alcohol, fizzy drinks, and caffeinated drinks)
Besides dietary changes, there are other lifestyle changes that can help to decrease IBS symptoms. Here are a few tips you can try:
Exercise more. Engaging in moderate aerobic activity like walking or cycling may improve IBS symptoms.
Stop smoking. There may be a link between IBS symptoms and smoking.
Get more sleep. Poor sleep habits may increase your IBS symptoms. Most people should aim for 7 to 9 hours of sleep each day.
There’s a strong association between stress and IBS. High levels of stress can make your IBS symptoms worse. And IBS symptoms can lead to more stress and anxiety. Fortunately there are some ways that can help you manage stress, including:
Counseling with a mental health provider
Hypnotherapy techniques
Mindfulness practices
The medications you use to treat IBS will differ based on your symptoms and IBS subtype.
WIth IBS-C, constipation is a frequent symptom. Over-the-counter (OTC) treatments that help to soften your stool may also provide some benefit.
Prescription medications for people who have IBS-C include:
In IBS-D, you tend to have loose stools more often. Treatment typically aims to reduce gut irritation and frequent bouts of diarrhea. OTC antidiarrheal medications may reduce your number of loose stools.
Common prescription medications to treat IBS-D include:
People with IBS-M have mixed symptoms. The symptoms tend to alternate between diarrhea and constipation. This can sometimes make it hard to find the right medication. In this case, dietary and lifestyle changes along with OTC symptom management may be most helpful.
Some medications help relieve the symptoms of IBS — no matter the subtype. These include:
Tricyclic antidepressants (TCAs): Medications like amitriptyline, nortriptyline, and desipramine decrease IBS symptoms by changing your perception of pain and improving your mood.
Antispasmodic medications: Medications like dicyclomine and hyoscyamine relax the muscles of the bowels and improve their movement. This can often improve abdominal pain and cramping and some of the stool changes with IBS.
Probiotics: Probiotics improve IBS symptoms by helping to balance the amount of bacteria that are normally in the bowels. This can decrease irritation in the bowels from an overgrowth of unhealthy bacteria.
There are many treatment options for the symptoms of IBS. Your healthcare provider will figure out the best treatment plan for you based on your medical history and symptoms.
IBS is a gastrointestinal (GI) disorder and not a mental health disorder. But there are some links between IBS and your mental health. People with certain mental health conditions also tend to have symptoms of IBS. These include:
Anxiety
Depression
Panic disorder
PTSD (post-traumatic stress disorder)
Schizophrenia
Experts don’t know the exact reason for the association. But studies show that managing your mental health can improve symptoms of IBS and your quality of life.
Both IBS and inflammatory bowel disease (IBD) as well as conditions like Crohn’s disease and ulcerative colitis are disorders that affect the GI tract. But IBS and IBD are very different.
IBS and IBD have some similar symptoms, including abdominal pain and stool changes. But in IBD you often have other symptoms that people with IBS don’t experience. These can include fevers, blood in the stool, weight loss, and joint pain.
Another difference is the condition of the bowels in IBS and IBD. Despite all of your IBS symptoms, your bowels usually look normal during a colonoscopy. With IBD, colonoscopies and other imaging tests can show severe inflammation.
IBS can cause significant symptoms and decrease your quality of life, but it’s not a life-threatening condition. There’s no cure for IBS. This may be because the exact cause isn’t known. But there are many treatments available for IBS, so you can get your symptoms under control.
American College of Gastroenterology. (n.d.). IBS FAQs.
American College of Gastroenterology. (n.d.). Low-FODMAP diet.
Annaházi, A., et al. (2014). Role of antispasmodics in the treatment of irritable bowel syndrome. World Journal of Gastroenterology.
Bonfrate, L., et al. (2017). Irritable bowel syndrome and diet. Gastroenterology Report.
Carabotti, M., et al. (2015). The gut-brain axis: Interactions between enteric microbiota, central and enteric nervous systems. Annals of Gastroenterology.
Ceccherini, C., et al. (2022). Evaluating the efficacy of probiotics in IBS treatment using a systematic review of clinical trials and multi-criteria decision analysis.Nutrients.
Chang, F. Y. (2012). Why do irritable bowel syndrome women often have nausea symptom?. Journal of Neurogastroenterology and Motility.
Fadgyas-Stanculete, M., et al. (2014). The relationship between irritable bowel syndrome and psychiatric disorders: From molecular changes to clinical manifestations. Journal of Molecular Psychiatry.
International Foundation for Gastrointestinal Disorders. (n.d.). Hypnosis for IBS.
International Foundation for Gastrointestinal Disorders. (n.d.). Psychological treatments.
International Foundation for Gastrointestinal Disorders. (2021). Cognitive behavioral therapy for IBS.
Johannesson, E., et al. (2015). Intervention to increase physical activity in irritable bowel syndrome shows long-term positive effects. World Journal of Gastroenterology.
Longstreth, G. F., et al. (2005). Functional bowel disorders. Gastroenterology.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Eating, diet, and nutrition for irritable bowel syndrome.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Symptoms and causes of irritable bowel syndrome.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Treatment for irritable bowel syndrome.
Nilsson, D., et al. (2021). Gastrointestinal symptoms and irritable bowel syndrome are associated with female sex and smoking in the general population and with unemployment in men. Frontiers in Medicine.
Office on Women's Health U.S. Department of Health and Human Services. (2021). Irritable bowel syndrome.
Posserud, I., et al. (2006). Functional findings in irritable bowel syndrome. World Journal of Gastroenterology.
Qin, H. Y., et al. (2014). Impact of psychological stress on irritable bowel syndrome. World Journal of Gastroenterology.
Rome Foundation. (2016). Rome IV criteria.
Saha, L. (2014). Irritable bowel syndrome: Pathogenesis, diagnosis, treatment, and evidence-based medicine. World Journal of Gastroenterology.
Trindade, I. A., et al. (2022). Quality of life in irritable bowel syndrome: Exploring mediating factors through structural equation modelling. Journal of Psychosomatic Research.
Werlang, M. E., et al. (2019). Irritable bowel syndrome and dietary interventions. Gastroenterology and Hepatology.
Xie, C., et al. (2015). Efficacy and safety of antidepressants for the treatment of irritable bowel syndrome: A meta-analysis. PLOS One.
Zejnelagic, J., et al. (2021). Chronic stress and poor sleeping habits are associated with self-reported IBS and poor psychological well-being in the general population. BMC Research Notes.