The biological approach is known as the medical model as it explains all behaviour through our biology. The biological approach sees OCD and other abnormalities in the same way it sees a physical illness, explaining it by abnormal biological processes.

Genetic explanations

These are hereditary influences transmitted from parent to offspring by genetic transmission.

• Researchers have identified?Candidate?genes?as genes that create vulnerability to OCD
• OCD seems to be?polygenic;?this means OCD is not caused by one single gene but by a combination of genetic variations that together cause significantly increased vulnerability
• There are?different types of genes?that cause OCD and one gene variation or group of genes may cause it in one person, but another sufferer of OCD could have a different variation of genes
• Taylor (2013)?found evidence from previous studies that there are up to?230 different genes?which may be involved with OCD
• Genes studied in relation to OCD include those involved in the action of?dopamine?and serotonin and both neurotransmitters are believed to have a role in regulating mood
• Tukel et al. (2013)?suggested a variation of the?COMT?gene may contribute to OCD as it is more common in patients who suffer from OCD than in those that do not. This variation produces?higher levels of dopamine and lower activity of the COMT gene
• The?5-HTT gene?has also been linked with OCD as it affects the levels of serotonin, making them less and these lower levels of the neurotransmitter are linked with OCD

Evaluation of genetic explanations

• OCD?can also be explained through neural connections and the imbalance or damage these can have.
• The neural damage may have been caused by illnesses that affect the immune system, such as different bacterias, and the explanation links to the genetic difference that has been found in?OCD?sufferers, where the gene, influences the levels of key neurotransmitters and the structures in the brain.

Neural explanations

• Serotonin?is known to play a role in regulating mood, if a person has?low levels of serotonin, the person can have low moods and other mental processes are often affected
• The reduction of serotonin can explain some cases of OCD
• Dopamine levels?are thought to be?abnormally high?in people who suffer from OCD
• Abnormal brain circuits:
  • The orbital Frontal Cortex (OFC),?sends signals to the thalamus about things that are worrying you, this area of the brain is overactive in people who suffer from OCD
  • The thalamus,?which is the part of the brain that instructs the person to do a certain activity or behaviour, in OCD sufferers, this would be the ODC behaviour
  • The caudate nucleus?is the part of the brain that in non-OCD suffers, surprises the messages from the OFC, and normalises the worry, however, in OCD suffers, this part of the brain is not completing this job and allows the OFC to make the sufferer worry. This could be due to damage or overstimulation
• Some forms of OCD have been linked with?poor decision-making, which could be down to abnormal functioning in the lateral parts of the frontal lobes. (the parts of the brain responsible for logical thinking and making decisions)

Evaluation of neural connections