Functional constipation, known as chronic idiopathic constipation (CIC), is constipation

Constipation

Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...

 that does not have a physical (anatomical) or physiological

Physiology

Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 (hormonal or other body chemistry) cause. It may have a neurological

Neurology

Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...

, psychological

Psychology

Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

 or psychosomatic cause. A person with functional constipation may be healthy, yet has difficulty defecating

Defecation

Defecation is the final act of digestion by which organisms eliminate solid, semisolid or liquid waste material from the digestive tract via the anus. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum...

.

Symptoms and diagnosis

Chronic idiopathic Constipation is similar to constipation-predominant irritable bowel syndrome

Irritable bowel syndrome

Irritable bowel syndrome is a diagnosis of exclusion. It is a functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and alteration of bowel habits in the absence of any detectable organic cause. In some cases, the symptoms are relieved by bowel movements...

 (IBS-C), however people with CIC do not have other symptoms of IBS, such as abdominal pain. Diagnosing CIC can be difficult as other syndromes must be ruled out as there is no physiological cause for CIC. Doctors will typically look for other symptoms, such as blood in stool, weight loss, low blood count, or other symptoms.

To be considered functional constipation, symptoms must be present at least a fourth of the time.

Functional constipation, as medically defined by the Rome III criteria, has many causes, including:

• Anismus
  Anismus
  Anismus is a malfunction of the external anal sphincter and puborectalis muscle during defecation. Normal defecation involves relaxation of both of these muscles...
  
  
• Descending perineum syndrome
• Hirschsprung's disease
  Hirschsprung's disease
  Hirschsprung's disease , or congenital aganglionic megacolon is a serious medical problem where the enteric nervous system is missing from the end of the bowel. The enteric nervous system is a complex network of neurons and glia that controls most aspects of intestinal function...
  
  
• Other inability or unwillingness to control the external anal sphincter, which normally is under voluntary
  Volition
  Volition may refer to:*Volition , the cognitive process by which an individual decides on and commits to a particular course of action...
  
   control
• A bad diet
  Diet (nutrition)
  In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...
  
  
• An unwillingness to defecate
• Nervous reactions, including prolonged and/or chronic stress and anxiety, that close the internal anal sphincter
  Sphincter ani internus muscle
  The Sphincter ani internus is a muscular ring that surrounds about 2.5 cm of the anal canal; its inferior border is in contact with, but quite separate from, the Sphincter ani externus....
  
  , a muscle
  Muscle
  Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
  
   that is not under voluntary control
• Deeper psychosomatic disorders which sometimes affect digestion
  Digestion
  Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
  
   and the absorption of water
  Water
  Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
  
   in the colon
  Colon (anatomy)
  The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...