Psychopathology- Evaluation OCD the Biological Appraoch To Explaining OCD

Question 1

✅ Nestadt

Answer 1

Nestadt (2010) shows for OCD; there is a high concordance rate between close family members. Non-identical twins have 31% concordance, and identical twins have 68%. MZ and DZ twins grow up sharing similar environments like food, upbringing and education, and life events like bereavement or parental divorce. This suggests that the additional shared DNA is responsible for the increased concordance.

Question 2

❌ correlation and cause

Answer 2

The correlation in family and twin studies does not automatically equal causation. it may not be the shared genetics behind the high concordance rates; closer family members also share similar environments; identical monozygotic twins may be treated more similarly because they look alike, compared to dizygotic, non-identical twins. As the concordance rate for identical twins at 68%, not 100%, the level we would expect for an entirely senetically determined psychological feature, so there must be some role for the environment.

Question 3

✅❌ The Diathesis stress response

Answer 3

The Diathesis stress response may be a more valid explanation for OCD than biological processes alone. Individuals inherit a genetic vulnerability to OCD (diathesis). However, the disorder does not develop unless there is an environmental factor (stressor), such as a traumatic life experience. Cromer showed 54% of 265 participants with OCD reported at least one traumatic life event, and those with traumatic life events reported increased severity of OCD symptoms; this demonstrates an environmental aspect of OCD.
hive disorder.

Question 4

✅ Several neuroimaging studies

Answer 4

Several neuroimaging studies using PET scanners have shown hyperactivity in the OFC and the caudate nucleus in people with OCD both while scanning the brain at rest and when symptoms are stimulated, but there is a problem with this neural evidence, it is correlational; researchers cannot be sure if the hyperactivity in these areas is the cause of OCD or a consequence of having OCD.

Question 5

✅❌ meta-analysis by Soomro

Answer 5

A meta-analysis by Soomro demonstrated SSRIs are more effective than placebos, suggesting there is a biological aspect to OCD, however despite altering levels of serotonin in the synapse within hours, these drugs take weeks to reduce symptoms, and 40% to 60% of patients show no or just partial symptom improvement. These findings suggest low levels of serotonin have a role to play in OCD but are not the sole