The biological approach to explaining OCD

Question 1

What is the biological approach?

Answer 1

• Emphasises the importance of physical processes in the body

Question 2

What are genetic explanations?

Answer 2

• Genes make up chromosomes, and consist of DNA
• Trasmission from parents to offspring

Question 3

What are neural explanations?

Answer 3

• Physical and psychological characteristics, determined by the behaviour of the nervous system
• Genes associated with OCD may affect levels of neurotransmitters and brain structures

Question 4

What did Lewis find that supports the genetic explanation for OCD?

Answer 4

• Observed OCD patients
• 37% had parents with OCD
• 21% had siblings with OCD
• Suggests a genetic link- genetic vulnerability through generations

Question 5

What is the diathesis-stress model?

Genetic explanation

Answer 5

• Certain genes make people more likely to develop a mental disorder
• Environment can trigger these genes

Question 6

What are candidate genes?

Genetic explanations

Answer 6

• Genes that create OCD vulnerability
• Involved in regulating serotonin development

Question 7

How is OCD polygenic

Genetic explanations

Answer 7

• Caused by a combo of genetic variations
• Taylor analysed findings of OCd studies, finding evidence of 230 genes being involved in OCD

Question 8

What does aetiologically heterogenous mean?

Answer 8

• OCD origins vary from one person to another
• Different groups of genes cause OCD

Genetic explanation

Question 9

What are the strengths of the genetic explanation?

Answer 9

• Research support
• Support from animal studies

Question 10

What are the limitations of the genetic explanation?

Answer 10

• Environmental risk factors
• Animal studies are flawed

Question 11

Strength:
I- Research support for the genetic explanation

Genetic explanation

Answer 11

D- Nestadt et al reviewed twin studies and found 68% of MZ twins share OCD vs 31% of DZ twins. Marini and Stebnicki found people with OCD diagnosed family members are 4X likely to develop OCD
E- Suggest there is some genetic influence on OCD development

Question 12

Limitation:
I- Environmental risk factors for OCD

Genetic explanation

Answer 12

D- OCD is not entirely genetic- environmental factors increase risk of development. Cromer et al found over 1/2 of OCD clients experienced a traumatic event
E- Means genetic vulnerability provides a partial explanation

Question 13

Evaluation extra:
- Animal studies

Genetic

Answer 13

Strength:
- Ahmari found particular gene variations are associated with repetitive behaviours in mice

Limitation:
- Mice and humans share more of their genes, but human brain is more complex (problem-solve, complex thoughts). Take caution when generalising

Genetic explanation

Question 14

What is the role of serotonin in OCD?

Neural explanation

Answer 14

• Serotonin regulates mood
• Neurotransmitters relay info from neuron to neuron
• Low serotonin levels= normal transmission of info does not occur, so experience of low mood

Question 15

What are decision-making systems?

Neural explanation

Answer 15

• OCD associated with impaired decision-making and unpleasant emotion
• Abnormal functioning of lateral of frontal lobes (decisions)
• Left parahippocampal gryrus (emotions)

Question 16

What are the strengths of the neural explanation?

Answer 16

• Research support
• Correlation and causality

Question 17

What are the limitations of the neural explanation?

Answer 17

• No unqiue neural system
• Correlation and causality

Question 18

Strength:
I- Research support for neural explanations

Neural explanation

Answer 18

D- Antidepressants, working on serotonin are effective in reducing symptoms. Symptoms form biological conditions (e.g: Parkinson’s). If a bio disorder produces OCD symptoms, it is likely the bio process underlies OCD
E- Suggests bio factors are responsible for OCD

Question 19

Limitation-
I- No unique neural system

Neural explanation

Answer 19

D- OCD patients often experience depression (co-morbidity). Depression involves serotonin activity disruption. Serotonin activity may be disrupted in people with OCD and depression
E- Means serotonin is irrelevant to OCD symptoms

Question 20

Evaluation extra:
- Correlation and causality

Neural

Answer 20

Strength:
- Some neural systems don’t work normally in OCD patients. Brain dysfunction comes first and causes OCD

Limitation:
- Abnormality and OCD relationship is a correlation- doesn’t indicate causal relationship. Trauma can influence OCD and neural abnormality