The Biological Approach Explaining OCD Flashcards
Genetic explanations
Explanations which focus on the role that genes play in the development of a mental disorder. This is because genes make up chromosomes and consist of DNA which codes for psychological features ms genes are transmitted from parents to offspring and are therefore inherited.
Neural explanations
Explanations which focus on the structure and function of the brain and nervous system in the development of a mental disorder.
Genetic explanation description
Genes are involved in an individual’s vulnerability to OCD. Lewis (1936) observed that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD. This suggests that OCD runs in families. However, it is thought that it is the genetic vulnerability to OCD that runs in families rather than a gene(s) that definitely produce OCD. The diathesis stress model suggests that certain genes leave some individuals more likely to suffer a mental disorder, but it is not certain. These individuals need some environmental stress (experience) that triggers the OCD. Therefore, the role of genes in developing OCD offers only a partial explanation.
Candidate genes
Researchers have found candidate genes that create vulnerability for OCD. Some of these genes are involved in regulating the development of the serotonin system - a neurotransmitter that is believed to be involved in OCD. One of the genes thought to be involved in OCD vulnerability is the gene 5HT1-D beta which is involved in the efficiency of transport of serotonin across synapses.
OCD is polygenic
OCD is polygenic meaning that it is not caused by one single gene but that several genes are involved. Taylor (2013) analysed finding of previous studies and found evidence that up to 230 different genes may be involved in OCD. These genes are thought to be associated with the action of dopamine as well as serotonin. Both of these neurotransmitters have a role in regulating mood.
OCD is aetiologically heterogenous
This means that the origin of OCD has different causes. One group of genes may cause OCD in one person, but a different group of genes may cause the disorder in another person. There is some evidence to suggest that different types of OCD, such as hoarding and religious obsessions, maybe due to particular genetic variations.
Neural explanations description
Neural explanations can be split into 3 areas:
1) Abnormalities in NEUROTRANSMITTERS that could be involved with the disorder
2) Abnormalities in brain STRUCTURE that could be involved with the disorder
3) Abnormalities in brain FUNCTION that could be involved with the disorder
Serotonin levels
Some cases of OCD are explained by a reduction in the functioning of the serotonin system in the brain meaning that less is produced. Serotonin is a neurotransmitter responsible for regulating mood. Low serotonin means that normal transmission of mood-relevant information between neurons does not take place and mood and other processes are affected. A mutation on the SERT gene may contribute to this.
Dopamine levels
Dopamine levels are thought to be abnormally high in people with OCD. High doses of drugs that enhance levels of dopamine in animals induce stereotyped movements resembling the compulsive behaviour found in OCD patients.
Decision making occurs in the lateral (side bits) frontal lobes. Abnormal functioning in the frontal lobes leads to impaired decision making. Impaired decision making is thought to be responsible for hoarding disorder.
Left parahippocampal gyrus
The left parahippocampal gyrus may also be involved in OCD. This area of the brain is associated with processing unpleasant emotions. It has been found to function abnormally in those with OCD.
