APA Dictionary of Psychology

a common functional disorder of the intestines characterized by abdominal pain or discomfort (e.g., bloating) and changes in bowel habits, with some people experiencing increased diarrhea, others increased constipation, and others alternating between the two. As yet there is no known cause (psychological or physiological), though stress and emotional factors are currently thought to play a role. Also called mucous colitis; spastic colitis.