Explanations of OCD Flashcards
Genetic explanation OCD- Serotonin and Dopamine
Serotonin genes are implicated in the transmission of serotonin across synapses.
Dopamine genes are implicated in OCD and may regulate mood.
Both are neurotransmitters
OCD - polygenic
Not caused by one single gene, but several genes. Taylor (2013) found evidence that up to 230 different genes may be involved in OCD
Genetic explanation OCD- Different types of OCD
one group of genes may cause OCD in one person, but a different group may cause the disorder in another- aetiologically heterogeneous.
Neural explanation OCD- serotonin
Neurotransmitters are responsible for relaying information from one neuron to another. If a person has low levels of serotonin then normal transmission of mood-relevant information does not take place and mood (and sometimes other mental processes) is affected
Neural explanation OCD- frontal lobes
some cases of OCD (e.g hoarding) are associated with impaired decision making. This is associated with abnormal functioning of the lateral (side) frontal lobes of the brain which are responsible for logical thinking and decision making.
Neural explanation OCD- Parahippocampal gyrus
Evidence suggests that the left Parahippocampal gyrus, associated with processing unpleasant emotions, functions abnormally in OCD
Strength of Genetic explanations for OCD- evidence
Nestadt et al (2010) reviewed twin studies and found 68% of identical twins shared OCD as opposed to 31% of nonidentical twins.
Marini and Stebnicki (2012) found that a person with a family member with OCD is around 4 times as likely to develop it as someone without it.
- People who are genetically similar are more likely to share OCD
Limitation of Genetic explanations for OCD- environment
There are also environmental factors that trigger the increase or risk of developing OCD. Cromer et al (2007) found in one sample over half of people with OCD had experienced a traumatic event. OCD severity correlated positively with the number of traumas. Therefore genetic vulnerability only provides a partial explanation.
Strength of the neural model for explanations of OCD- evidence
Antidepressants that work on serotonin reduce OCD symptoms. Suggests that serotonin may be involved in OCD. OCD symptoms form part of conditions that are biological in origin (eg. Parkinson’s disease) (Nestadt et al 2010). Biological factors (e.g serotonin and processes underlying Parkison’s disease) are likely involved in OCD.
Limitation of the neural model for explanations of OCD- no unique neural system
Many people with OCD experience depression. This involves disruption to the action of serotonin. It could be that serotonin is disrupted in many with OCD because they are depressed as well. This means that serotonin may not be relevant to OCD symptoms.
