From: The role of serotonin and diet in the prevalence of irritable bowel syndrome: a systematic review
| Study | Number of Patients | Percentage of participants with psychological illness |
|---|---|---|
| Blanchard et al (2007) | 210 |
66.6% (DSM-IV Axis type-1 disorder) |
| Kennedy et al (2005) | 149 | 43% (Any psychological disorder in the past year) |
| Payne and Blanchard (1995) | 34 |
85% (DSM-IV Axis type-1 disorder) |
| Tkachuk et al (2003) | 28 | 68% (DSM-IV Axis type-1 disorder) |