Obsessive compulsive disorder

Biological Factors

Some mental health researchers suggested that research on brain scans indicates that OCD is linked to a genetic or biological cause. This research is often described in terms of chemical imbalances in the brain, faulty brain circuitry or genetic defects. Brain scans show that some parts of the brain of people with OCD are different from those of people without OCD. However, it is still not clear how these differences relate to how OCD works. The cortex and basal ganglia regions are most heavily involved, as cortical and basal ganglia blood flow patterns are consistently different in those with OCD compared to those without the disorder. However, further analyses revealed that differences between patients with OCD and healthy controls were consistently detected only in the orbital gyrus and the head of the caudate nucleus. In 1998, it was found that infections may have caused OCD in a small percentage of children. This showed that the basal ganglia are a key part of the brain for OCD. Streptococcal infections trigger an immune response, which in some individuals generates antibodies that cross-react with the basal ganglia. It is thought that the body’s natural response to a throat infection, the production of certain antibodies, when directed to parts of the brain might be linked in some way to Paediatric Autoimmune Neuropsychiatric Disorders associated with Streptococcal Infection (PANDAS). later in 2004 study found no link between subsequent infections and exacerbation of symptoms. Hence the researchers concluded that PANDAS, despite not being a cause of OCD, activates symptoms in children who are genetically or otherwise prone to develop the illness.

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  Genetic Factors.
  

Overall, genetic studies show that there is a small family tendency toward anxiety. Some research shows that people with OCD may have a family member with OCD or another condition on the "spectrum." Research done in 2001 found that people with OCD are four times more likely to have a family member with the same disorder.
This and other studies have shown that OCD can run in families, which has led to the search for genetic factors. Researchers have done dozens of studies and looked at many possible genes, but they still haven't found an OCD gene. Many people with OCD or other anxiety disorders don't realise that it runs in their families. If identical twins were talked to, and one had OCD and the other didn't, this idea might be called into question even more. This shows that OCD may not be caused by genes alone and that it may be possible to learn to have OCD in your family. Genes can't be ruled out, but learned behaviours or the environment may be more important.

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