OCD: Biological Approach

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Genetic and Neural Explanations of OCD

It is possible that OCD may be partially caused by a genetic tendency for the condition, and that the neural OCD circuit may play an important role. But there is a lack of research in both areas.

Genetic statistics

The results of family and twin studies suggest that OCD has a moderate genetic component.
The disorder is five times more frequent in the first-degree relatives of people with OCD than in people without the disorder.
The concordance rate of OCD among identical twins is around 57% but the concordance rate for fraternal twins is 22%.
- If a pair of twins are concordant, both are affected by the disorder.

OCD gene

Studies have found about two dozen potential genes that may be involved in OCD. These genes regulate the function of three neurotransmitters: serotonin, dopamine, and glutamate.
Many of these studies included small sample sizes and have yet to be replicated.
So additional research needs to be done in this area.

Orbitofrontal cortex

The orbitofrontal cortex is a brain region believed to play a critical role in OCD. It is an area of the frontal lobe involved in learning and decision-making.
In people with OCD, the orbitofrontal cortex becomes especially hyperactive when they are provoked with tasks in which, for example, they are asked to look at a photo of a toilet or of pictures hanging crookedly on a wall.

OCD circuit

The orbitofrontal cortex is part of a series of brain regions that, collectively, is called the OCD circuit. The OCD circuit is made up of several interconnected regions that influence the perceived emotional value of stimuli and the selection of both behavioural and cognitive responses.
As with the orbitofrontal cortex, other regions of the OCD circuit show heightened activity during symptom provocation. This suggests that abnormalities in these regions may produce the symptoms of OCD.
People with OCD also show a substantially higher degree of connectivity of the orbitofrontal cortex and other regions of the OCD circuit than those without OCD.

Limitations of neural findings

The findings on the neural bases of OCD were based on imaging studies, and they highlight the potential importance of brain dysfunction in OCD.
But one important limitation of these findings is that they don't explain differences in obsessions and compulsions.
Another limitation is that the correlational relationship between neurological abnormalities and OCD symptoms cannot imply causation.

Biological Approach to Treating OCD

The biological approach treats OCD using anti-anxiety and anti-depressant drugs.

Biological approach

The biological approach tries to treat psychological disorders directly by influencing the chemistry of the body and the brain.

Anti-anxiety drugs

Some anti-anxiety drugs, or ‘anxiolytics’, treat OCD by tackling anxiety directly.
Drugs such as Valium increase levels of GABA in the brain — a neurotransmitter responsible for inhibiting other neurons. This helps to calm people down.

Mood modifiers

Other forms of medication try to tackle people’s thoughts and mood.
A drug called sertraline was initially developed as an anti-depressant, but is widely prescribed for OCD because it helps to boost mood and reduce the tendency to worry.

Limitations of anti-depressant drugs

A limitation of anti-depressant drugs, such as sertraline, is that they can take four to six weeks to take effect.
All drugs also have side effects, but these vary from person to person.
- One person may find the side effects mild, while another person may need to switch to a different medication.