Ive heard about it but, no one has ever told me what the causes are.

[pachyderm]

> no one has ever told me what the causes are.

Many of "them" don't know. They appear not to feel they should know.

My ideas: it is a mental mechanism to "bind" anxiety by enclosing it with invented "regularities." An internal mental/emotional "system" is out of balance and is trying to restore itself and finds obsessive and compelled things the only way to try to do it. Of course those things are only partly successful, because they don't restore the damage that caused the system to get out of balance in the first place. The damage that caused the anxiety in the first place. You have to find out what that was, to root out the root causes.

[Perna]

From: http://www.ocfoundation.org/what-is-ocd.html

There is no proven cause of OCD. Research suggests that OCD involves problems in communication between the front part of the brain (the orbital cortex) and deeper structures (the basal ganglia). These brain structures use the chemical messenger serotonin. It is believed that insufficient levels of serotonin are involved in OCD. Drugs that increase the brain concentration of serotonin often help improve OCD symptoms.

Pictures of the brain at work also show that the brain circuits involved in OCD return toward normal in those who improve after taking a serotonin medication or receiving cognitive-behavioral psychotherapy. Although it seems clear that reduced levels of serotonin play a role in OCD, there are no laboratory tests for OCD. The diagnosis is made based on an assessment of the person's symptoms. When OCD starts suddenly in childhood in association with strep throat, an autoimmune mechanism may be involved, and treatment with an antibiotic may prove helpful.

[LizardL8y]

In a general psych class the professor said that it is kind of like the front of your brain is short-circuting and thoughts then get repeated over and over again until the increased activity in that part of the brain calms down. She said anxiety triggers that short-circut and that that is where obsessive thought comes from. She said nobody knows for sure what causes some people's brains to have that reaction to anxiety while others don't but like said above it may have to do with the neurotransmitter seratonin properly connecting to the receptor nerves.