There are three types of irritable bowel syndrome, or IBS.
They include:
IBS with constipation
This comes with stomach pain and discomfort, bloating, abnormally delayed or infrequent bowel movement, or lumpy/hard stool.
IBS with diarrhea
This comes with stomach pain and discomfort, an urgent need to move your bowels, abnormally frequent bowel movements, or loose/watery stool.
IBS with alternating constipation and diarrhea.
There are about an equal number of people with IBS in each category. There is also evidence that most people with IBS will alternate between types over time.
"It is not entirely clear how stress, anxiety, and irritable bowel syndrome (IBS) are related -- or which one comes first -- but studies show they tend to co-exist. "If you do diagnostic interviews, what you find is that about 60% of IBS patients will meet the criteria for one or more psychiatric disorders," read more....
http://www.webmd.com/ibs/types-ibs