OCD Explanation - Biological

Question 1

Genetic: polygenic

Answer 1

A number of candidate genes have been implicated as a possible cause for OCD e.g Taylor (2013) identified up to 230, suggesting OCD is polygenic.

Question 2

Genetic: Aetiological heterogeneity

Answer 2

Different combinations of genes may cause the disorder in different people, this may also account for different types of ocd.

Question 3

Genetic: COMT gene

Answer 3

This gene regulates the production of dopamine which is a neurotransmitter implicated in OCD. The OCD variation of this gene results in lower activity of the COMT gene and high levels of dopamine.

Question 4

Genetic: SERT gene

Answer 4

The SERT gene variation affects the transport of serotonin, creating lower levels of this neurotransmitter. Evidence shows that low levels of serotonin are associated with OCD.

Question 5

Neural: neurotransmitters

Answer 5

The role of these neurotransmitters are associated with abnormal with abnormal transmission of mood-related obsessive thoughts.
- dopamine levels are abnormally high in people with OCD.
- lower serotonin levels are associated with OCD.

Question 6

Neural: Structural deficits

Answer 6

• hyperactivity in the basal ganglia is linked to repetitive actions (compulsions).
• the orbito-frontal cortex (the worry circuit) can have faulty areas which leads to inability to filter small and large worries in OCD so worry circuit is overactive.

Question 7

Diathesis - stress

Answer 7

Individual genes may create a vulnerability for OCD which is then expressed only if particular stressors are present. Some people could possess gene variations but suffer no stressors and therefore no OCD.

Question 8

Strength: Evidence for genetic explanations (and counter)

Answer 8

• Mz twins are more than twice as likely to develop OCD if their co twin has OCD (supports of genetic vulnerability for ocd as it shows people that are genetically similar are more likely to share OCD).
  However concordance rates aren’t 100% which suggests other factors e.g environmental are present as the twins grow up in the same environment and they observe and imitate each other.

Question 9

AO3: Weakness for neural treatments (and counter)

Answer 9

• Many people who experience OCD also experience depression. Depression likely involves disruption to the action of serotonin. Therefore, serotonin may not be relevant to OCD symptoms, as it could just be disrupted due to the depression they are experiencing and NOT the OCD. HOWEVER, Pigott et al (1992) found that antidepressant drugs that increase serotonin activity have been seen to reduce OCD symptoms – this suggests that serotonin may be involved in OCD