Possible Causes of Obsessive Compulsive Disorder (OCD)

The exact cause of obsessive compulsive disorder (OCD) is unknown. Chemical imbalances, malfunction and overactivity in the brain, genetics and environment may all play a role in the disorder.

Seretonin

The neurotransmitter serotonin is believed to play a role in OCD. Serotonin assists nerve cells in communicating with each other. The neurotransmitter plays a part in many facets of brain function--all of which are not fully understood--but serotonin is known to affect mood, sleep and pain sensations. People with OCD may have low levels of serotonin or they may have malfunctioning brain receptors that do not effectively pickup the serotonin. SSRI medications reduce symptoms in some OCD patients, giving credence to the theory that serotonin plays a role in the disorder. SSRI medications work by blocking the brain from reabsorbing serotonin, thereby leaving the neurotransmitter available for use by nerve cells.

Brain Dysfunction

Imaging scans of OCD sufferers commonly show abnormalities and overactivity in several areas of the brain, including the orbital cortex, basal ganglia and thalamus. These are structures of the brain that play a part in sensory processing, emotions and organization, and they do not communicate properly in people with OCD.

Depression, Stress and Hormones

Depression, stress and hormone fluctuations can cause temporary obsessive compulsive type symptoms in people without OCD and can exacerbate symptoms in people who have obsessive compulsive disorder. Premenstrual syndrome, pregnancy and menopause can increase OCD symptoms. People with OCD commonly develop depression and anxiety disorders due to the stress of the disorder. Dealing with multiple disorders--OCD and depression--unfortunately, makes treatment more difficult.

Genetics

OCD is known to run in families, which means defective genes most likely are partly responsible for the disorder. The inheritance of genes are not the only cause of OCD, however, because the disorder can develop in one twin and not the other. Environmental factors and stress likely play a part as well. Scientific studies do not agree on the percentage of genetic related OCD. The OCD Foundation quotes expert opinions that estimate 45 to 65 percent of OCD that begins during adolescence and 27 to 47 percent of OCD that begins in adults is due to genetics.