OCD Risk Factors

Risk factors for obsessive-compulsive disorder include the following:

  • Heredity (Genetics)
  • Postpartum periods
  • Environmental stressors

OCD & Genetics

Although there is no clear genetic evidence, obsessive-compulsive disorder tends to run in families. A person with OCD has a 25 percent chance that a blood relative also has the disorder. Like other mental illnesses, OCD is more prevalent among identical twins than fraternal—a 70 percent chance that identical twins with share it, compared to a 50 percent chance for fraternal twins. Currently, researchers do not understand OCD's genetic mechanisms, though they suspect multiple genes are involved.

OCD & Pregnancy

Women with OCD may experience a worsening of symptoms during pregnancy and postpartum. A recent study suggests that fluctuating hormones may trigger symptoms during pregnancy. The same study reports OCD in 30 percent of women observed.

The arrival of a baby brings new responsibility, a new set of concerns, and changes in routine. While normal reaction to a newborn may include some anxiety, postpartum OCD features disturbing thoughts and excessive behavior regarding the baby's well-being. The following obsessions and compulsions are common:


  • Fear of contaminating the baby
  • Need for reassurances
  • Recurrent fear for the baby's safety
  • Recurrent thoughts of bad mothering
  • Recurrent thoughts of harming the baby
  • "Thoughts of disturbed order"


  • Repeatedly washing the baby
  • Repetitively calling the physician
  • Incessantly checking the baby
  • Avoiding or neglecting the baby
  • Ordering and rearranging baby's crib

These feelings and behaviors may occur immediately, but often begin 4 to 6 weeks after giving birth. Treatment is necessary to control symptoms and to ensure care of the baby.

OCD & Environment

Environmental stressors that can worsen OCD symptoms include the following:

  • Abuse
  • Changes in living situation
  • Illness
  • Occupational changes or problems
  • Relationship concerns
  • School-related problems

OCD Causes

Biological factors involving brain structure and activation are associated with OCD. Abnormalities of the frontal lobes, basal ganglia, and cingulum are common in people with OCD. Basal ganglia are involved in routine behaviors, like grooming, and the frontal lobes in organizing behaviors and in planning. The cingulum consists of fibrous bands that assist in communicating the brain's behavioral and emotional messages. Support for its role in OCD is the fact that surgical severing of the cingulum has relieved and even cured people with the disorder.

OCD & The Serotonin Hypothesis

An abnormally low level of serotonin is perhaps the most well-established link between the brain and OCD. Serotonin is a chemical neurotransmitter that transmits information from one nerve to another throughout the brain. It is released by one synapse (nerve ending), crosses a gap, and is picked up by another synapse. After a message is sent, enzymes in the brain clean serotonin out of the synapses. Drugs used to treat OCD, known as selective serotonin reuptake inhibitors (SSRIs), increase and sustain serotonin levels and reduce or eliminate symptoms.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 31 Jan 2001

Last Modified: 28 Sep 2015