Is ibs(irritable bowel syndrome) a true medical condition ?

Yes: In fact the gastroenterology society has strict guidelines on describing it. One such guideline is the rome criteria which distinguishes between ibs that is constipation or diarrhea predominant.

Yes.: In ibs, the bowel looks normal, even under the microscope. But it reacts to stimuli differently than normal bowel does. For instance, distention that does not cause pain in a normal bowel can cause a great deal of pain in someone with ibs. There is ongoing research on this.