The gut and brain are in constant communication via the gut–brain axis. This means changes in one can affect the other. This is known as, and it’s one of the reasons researchers have started exploring whether low-dose antidepressants might help improve IBS symptoms.
In a large 2023 UK study, people with IBS who took low-dose amitriptyline (a tricyclic antidepressant) experienced meaningful improvements in their symptoms compared to those taking a placebo.
👉 Around 61% reported feeling relief after 6 months.
👉 Abdominal pain scores dropped significantly.
👉 Most people tolerated it well, with only mild side effects like drowsiness or dry mouth.
Interestingly, the benefits weren’t linked to changes in mood — suggesting these low doses may work by reducing gut pain sensitivity and supporting motility, not by treating depression.
This doesn’t mean antidepressants are a cure or the right choice for everyone — but for some, they can be a helpful second-line treatment when diet and lifestyle changes alone aren’t enough.
💬 Always speak with your GP before starting any medication, and remember — IBS is complex, and relief often requires a whole-body approach.
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💬 Have you ever been offered amitriptyline for IBS? What was your experience?
FULL BLOG: Can Antidepressants Help Improve IBS Symptoms?
We know that IBS is a disorder of the gut-brain axis, this has led people to question if using antidepressants can have an effect on the gut symptoms seen in IBS? After all, what happens in the brain has an effect on the gut and vice versa.
While this was originally thought to be the reason why antidepressants may help improve the symptoms of IBS, it is interesting to note that previous trials have suggested that the beneficial effects may be due to antidepressants effect on pain and GI motility rather than their effect on mood, due to the low doses used in IBS.
There is no singular cause for IBS, it is multifactorial. This has made finding a one size fits all treatment for IBS very difficult. The majority of the medications used in IBS treat the individual symptoms rather than treating IBS itself.
Are Antidepressants Recommended as a Treatment for IBS?
The UK National Institute For Health and Care Excellence (NICE) recommends dietary and lifestyle changes and medications including laxatives, antispasmodics (which help with stomach pains) and antidiarrheals as the first line treatment for IBS. If these interventions do not work, NICE guidelines state that GPs should consider low dose tricyclic antidepressants for their analgesic (pain relieving) effect as a second-line Treatment.
However under 10% of GPs prescribe tricyclic antidepressants for IBS and only 50% of GPs believe they are effective for the treatment of IBS. This can be very frustrating for patients, as it means a potential treatment option is not being utilised.
Are There Any Studies Looking at Antidepressants as a Treatment for IBS?
A 2023 study was conducted to investigate the effectiveness of the tricyclic antidepressant, amitriptyline in the treatment of IBS in the primary care setting. Most patients with IBS are seen by their GPs in the community. Therefore it was important that the experiment was conducted in the community so that it reflected real life practice.
The experiment was a randomised, double blind, placebo-controlled trial. This is a mouth full, however, it means that the experiment set up was of a gold standard.
The experiment involved 463 people from 55 different GP practices in the UK. The participants were all over 18, had a diagnosis of IBS and had ongoing IBS symptoms despite following first line dietary and lifestyle Advice.
Half of the participants were given low dose amitriptyline and half were given a placebo, for 6 months. A placebo is a treatment, in this case a tablet, that is given to make people think they are being given a medicine, however it has no effect, it may as well be a sweet. The group given the placebo are known as the control group.
The dose of the antidepressant was started at a low dose, 10mg a day. Patients had the option to increase their dose to 30mg a day depending on their side effects and symptom response. Patients were asked on a weekly basis, ‘Have you had adequate relief from your IBS symptoms?’.
Overall lBS symptoms were assessed at 3 and 6 months.
So, Does Taking an Antidepressant Reduce IBS Symptoms? Yes, low dose amitriptyline led to a greater reduction in IBS symptoms in comparison to the control group
- Low dose amitriptyline led to a significant reduction in the IBS symptom severity score, with an average reduction of almost 100 points at both 3 and 6 months
- At 6 months, 61% of those taking low dose amitriptyline had relief from their IBS symptoms as measured via the subjective global assessment (SGA), versus only 45% of those in the control group
- 41% of those taking low dose amitriptyline, versus 30% of those taking the placebo had relief from their IBS symptoms for half of the weeks throughout the 6 months
- At 6 months, 74% were still taking low dose amitriptyline, while only 68% were still taking the control. This shows that participants were happier to continue taking the antidepressant than the placebo, possibly due to the symptom relief they were getting from the low-dose amitriptyline
- Significantly more participants in the low dose amitriptyline group had a 30% or more reduction in abdominal pain severity, however not in abdominal distension severity
- When looking at participants who had considerable or complete symptom relief, low dose amitriptyline was seen to have a greater effect
- 13% of participants stopped taking the low dose amitriptyline due to adverse events, while 9% stopped taking the placebo due to adverse events. Adverse events were mainly reported to be mild side effects e.g. drowsiness or dry mouth
Interestingly, there was no effect on somatoform (feeling pain in response to psychological distress) symptom reporting, anxiety, depression or work and social adjustment scores at 6 months. This supports the suggestion that low dose amitriptyline improves IBS symptoms via its effects on pain and gut motility, rather than having an effect on anxiety or depression.
Of note 80% of participants had diarrhoea predominant or mixed IBS, meaning that it is more difficult to judge the effectiveness of low dose amitriptyline in those with constipation prone IBS. Hopefully further studies will look at the effect of low dose amitriptyline in those with Constipation.
This study concluded that, at a low dose the antidepressant, amitriptyline, led to an improvement in IBS symptoms and that it was safe and well tolerated by participants. It is hoped that this experiment will lead to a greater acceptance of the use of amitriptyline in the treatment of IBS.
Reference: Amitriptyline at Low-Dose and Titrated for Irritable Bowel Syndrome as Second-Line Treatment in primary care (ATLANTIS): a randomised, double-blind, placebo- controlled, phase 3 trial
Alexander C Ford*, Alexandra Wright-Hughes*, Sarah L Alderson, Pei-Loo Ow, Matthew J Ridd, Robbie Foy, Gina Bianco, Felicity L Bishop, Matthew Chaddock, Heather Cook, Deborah Cooper, Catherine Fernandez, Elspeth A Guthrie, Suzanne Hartley, Amy Herbert, Daniel Howdon, Delia P Muir, Taposhi Nath, Sonia Newman, Thomas Smith, Christopher A Taylor, Emma J Teasdale, Ruth Thornton, Amanda J Farrin†, Hazel A Everitt†, on behalf of the ATLANTIS trialists
