A shared communication network called the “gut-brain axis” may partially explain the connection between PTSD, a mental health condition, and IBS, a functional disorder of the gastrointestinal system.

Post-traumatic stress disorder (PTSD) is a mental health condition that occurs after experiencing or witnessing trauma. It features symptoms and signs like intrusive thoughts and flashbacks as well as behaviors of avoidance, reactivity, and heightened arousal.

Gastrointestinal (GI) symptoms are common in PTSD. When the symptoms become persistent, lasting several months or longer, they may meet the diagnostic criteria for irritable bowel syndrome (IBS).

The link between PTSD and IBS isn’t clear. No direct cause-and-effect relationship has been found, but living with PTSD may increase your risk of IBS.

According to a review of studies from 2018, people living with PTSD are 2.8 times more likely to have IBS compared with people without PTSD.

It remains unclear if PTSD directly leads to IBS or if the same risk factors that make you susceptible to experiencing PTSD also make you susceptible to developing IBS.

How does PTSD affect the digestive system?

PTSD doesn’t always cause GI distress, but, when it does, your gut-brain axis and natural stress response might have something to do with it.

Your GI system and your brain are linked by a communication pathway known as the “gut-brain axis.”

Through this neural network, which includes the vagus nerve, your brain helps regulate GI functions such as digestion speed and blood flow. Your gut also helps produce neurotransmitters and chemicals involved in mood and cognitive function.

The connection of your gut-brain axis is why you might experience an upset stomach when you’re upset, for example, or why certain foods can affect your mood.

Your stress response also affects the gut-brain axis. When your brain perceives a stressor, it kicks off a multitude of physiological responses to help you overcome the present challenge.

For your GI system, this means slowing down digestion, changing intestinal permeability, increasing inflammation, and heightening sensitivity to stimuli, among many other effects. These changes result from communication from your brain to your gut through their neural connection.

Because PTSD is a condition of chronic psychological stress, it can create a persistent stress response in the body that may have long-term effects on your GI function.

GI discomfort and IBS appear to be common in people living with PTSD.

A study from 2022 among veterans living with PTSD found that 25% had symptoms that met the diagnostic criteria for IBS. The most common GI symptom experienced in the research was abdominal pain, followed by diarrhea and constipation, with gas and bloating as the least common GI symptom.

You can experience gastrointestinal (GI) difficulties with PTSD and not be living with IBS. “IBS” refers to persistent abdominal pain with two or more accompanying symptoms related to your bowel movements.

IBS can be diagnosed when symptoms have been present for 6 months and have been present at least once a week during the last 3 months.

If your condition has been diagnosed as PTSD, signs or symptoms that you may also be experiencing IBS include:

  • abdominal pain, often specific to having a bowel movement
  • diarrhea
  • constipation
  • bloating/excessive gas production
  • feeling as though you can’t entirely complete a bowel movement
  • white mucus in your stool
  • worsening GI symptoms during your period

Because no direct cause-and-effect link between PTSD and IBS has been established, it’s possible to experience these conditions simultaneously (comorbidly) but with symptoms occurring independently of one another.

This means that even when comorbid, symptoms of PTSD may not be accompanied by GI distress, and you may experience GI distress without active PTSD symptoms.

PTSD and IBS may be more closely linked if you mainly experience IBS symptoms when PTSD symptoms flare.

PTSD and IBS have different treatment focuses but share some therapeutic approaches.

PTSD is primarily treated through psychotherapy. Psychotherapy, also known as “talk therapy,” centers on communication-based interventions between you and a mental health professional.

Cognitive behavioral therapy (CBT) is the gold standard in PTSD psychotherapy. The American Psychological Association indicates there are 4 variations of CBT strongly recommended for the treatment of PTSD, including:

  • cognitive processing
  • cognitive therapy
  • prolonged exposure
  • traditional CBT

Through these approaches, a therapist can guide you to identify unhelpful thought patterns in PTSD and work with you to change those patterns. When you’re ready, you’re gradually asked to face the traumatic experience you went through in a safe and controlled way.

IBS is a functional GI disorder, which means IBS doesn’t arise from damage or structural changes in your GI system. Treatment typically involves managing symptoms with medications and making lifestyle changes, like eating more fiber, that help improve GI function.

Psychotherapy, including CBT, can be a part of IBS treatment. CBT for IBS focuses on managing thoughts about IBS that might exacerbate symptoms, such as fixating on worst-case scenarios. CBT can also help you develop new coping skills and relaxation techniques.

If your IBS symptoms flare from anxiety in certain situations, you may benefit from exposure therapy, similar to that used in PTSD treatment.

IBS symptoms may improve through PTSD treatment if PTSD is exacerbating your symptoms.

PTSD is a mental health condition that increases the chances of experiencing IBS, a functional disorder of the GI system. While no direct cause-and-effect link has been established between PTSD and IBS, PTSD may contribute to GI distress through the gut-brain axis.

IBS and PTSD are treated separately, but both may involve psychotherapy approaches, such as CBT, which address unhelpful thought patterns and behaviors.