Biological approach to explaining OCD

Question 1

Outline the genetic explanation for OCD.

Answer 1

Candidate genes: e.g. 5HT1-D beta– leads to decreased serotonin at the synapse
OCD is polygenic - combination of up to 230 genes that increase vulnerability
230 - different genes are involved in different types of OCD

Question 2

Outline neural explanations for OCD.

Answer 2

Low levels of the neurotransmitter serotonin leads to lower mood and can also impact other mental processes
Orbitofrontal cortex hyperactive – affects decision making and impulse control

Question 3

Evaluate the genetic explanation.

Answer 3

Strengths:
+Research support: 37% (Lewis) of OCD patients had a parent with OCD and 21% had a sibling with OCD
+Research support: 68% concordance rate in monozygotic (MZ) twins compared to 31% in dizygotic twins (DZ) (Nestadt et al)
+Research support in animal studies: Ahmari et al (2016) found that particular genes associated were with repetitive behaviors in rats.
Weaknesses:
-Counterpoint: Diathesis – stress model can explain genetic vulnerability and interaction with triggers so is a better explanation
-Counterpoint: Environmental factors: Over half of OCD patients had also experienced a traumatic event and OCD was more severe the more trauma experienced.
-Counterpoint: we cannot generalize to humans.

Question 4

Evaluate the neural explanations.

Answer 4

Strengths:
+Real world application: SSRI’s can be used to reduce symptoms of OCD
+Research support: fmri scans show brain activation in OFC.
Weaknesses:
-Counterpoint: Treatment-causation fallacy – just because drug therapy is effective, it does not mean there is a biological cause.
-Counterpoint: Co-morbidity: many people with OCD also have clinical depression which makes it difficult to distinguish the associated symptoms of each condition.
-Correlational: No cause-effect relationship established.