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Irritable Bowel Syndrome (IBS)

Common, genuine, and treatable — despite often being dismissed for years.

Irritable bowel syndrome is a disorder of gut-brain communication causing recurrent abdominal pain linked to altered bowel habits. There's no structural damage on tests, which is why IBS is defined by symptom criteria rather than a biopsy. First-line treatment targets diet, stress, and specific symptoms rather than a single drug.

Causes & risk factors

  • Altered gut motility and sensitivity
  • Gut-brain axis disturbances (anxiety, depression often coexist)
  • Post-infectious IBS after a gastroenteritis episode
  • Food triggers — often FODMAPs, caffeine, or alcohol
  • Genetic predisposition

Symptoms

  • Recurrent abdominal pain or cramping
  • Bloating and visible abdominal distension
  • Constipation, diarrhoea, or alternating between the two
  • Mucus in stool
  • Relief of pain after a bowel movement

How it's diagnosed

  • Rome IV symptom criteria
  • Blood count, CRP, coeliac serology to exclude inflammation or coeliac disease
  • Faecal calprotectin when inflammatory bowel disease is a concern
  • Referral for colonoscopy if red flags (bleeding, weight loss, age over 50)

Evidence-based treatment

  • Low-FODMAP diet trialled for 4–6 weeks under supervision
  • Soluble fibre (psyllium) for constipation-predominant IBS
  • Antispasmodics (mebeverine, peppermint oil) for cramping
  • Laxatives or anti-diarrhoeals based on subtype
  • Gut-directed CBT or hypnotherapy for refractory cases

Prevention

  • Identify and avoid personal trigger foods with a symptom diary
  • Regular meal timing; avoid skipping meals
  • Stress management — exercise, sleep, therapy if anxiety is driving flares

Related symptoms

Irritable Bowel Syndrome (IBS) — FAQ

Is IBS the same as inflammatory bowel disease?

No. IBS is a functional disorder with no visible inflammation or tissue damage. Inflammatory bowel disease (Crohn's, ulcerative colitis) involves actual intestinal inflammation and needs very different treatment.

Can stress cause IBS?

Stress doesn't cause IBS outright, but it can trigger and worsen flares via the gut-brain axis. That's why behavioural therapies work.