Explaining OCD Flashcards
Genetic Explanation - COMT and SERT
A - COMT gene - involved in production of COMT which regulates production of dopamine which is implicated towards OCD. High levels.
- SERT gene - affects transport of serotonin causing lower levels. Linked to OCD as well as higher levels. Need both genes for OCD
Genetic Explanation - Polygenic
- Polygenic genes - several genes involved. Taylor analysed findings of previous studies and found evidence of up to 230 genes involved in OCD.
Genetic Explanation - AH Genes
- Group of genes cause OCD but different group may cause disorder in different person.
- Different types of OCD involve different genes or groups of genes.
- Each case of OCD has different causes.
- Anyone could have OCD.
- OCD different in everyone.
Evaluation of Genetic Explanation - supporting twin research
- Billet et al carried out a meta analysis of 14 twin studies of OCD and found, on average, MZ twins were twice as likely to develop OCD if their co twin had the disorder, than was the case for DZ twins, highlight the strong genetic component.
- Strength - adds validity.
Evaluation of Genetic Explanation - Family Support
- Studies of first degree relatives and twins studies provide evidence .
- Nesadt et al identified 80 patients with OCD and 343 of their first degree relatives and compared them with 73 control patients without mental illness and 300 of their relatives. Found that people with first degree relative with OCD had a 5 times greater risks of having OCD compared to control group.
- Strength - Adds validity.
Evaluation of Genetic Explanation - too many candidate genes
- Psychologists not successful at pinning down genes involved with OCD.
- Several genes are involved and each genetic variation only increases the risk of OCD by a fraction.
- Weakness - explanation unlikely to be useful as it provides little predictive value.
Evaluation of Genetic Explanation - Environmental Influence
- Environmental factors can also trigger or increase the risk of OCD.
- Cromer found that over half of OCD patients in their sample had a traumatic event in their past and OCD was more severe in those with more than one trauma.
- Weakness - suggests that OCD is not entirely genetic. May be more productive to focus on environmental factors as we are able to do something about these.
Neural Explanation - abnormal levels of neurotransmitters
- Dopamine levels thought to be abnormally high in OCD patients. Based on animal studies.
- Lower serotonin levels associated with OCD.
Neural Explanation - Abnormal brain circuits
- Caudate nucleus in basal ganglia does not suppress worry signals from orbitofrontal cortex.
- Orbtiofrontal cortex sends worry signals to thalamus.
- When caudate nucleus is damaged it fails to stop worry signals and have difficulty switching off and obsession starts.
- Supported by PET scans.
- Abnormal Serotonin levels caused Caudate nucleus to malfunction.
- High Dopamine levels causes Basal Ganglia to malfunction.
Evaluation of Neural Explanation - Supporting Evidence
- Some antidepressants work purely on serotonin system and increases it’s levels and effective in reduction OCD symptoms.
- Strength - suggests that serotonin system is involved therefore adds validity.
Evaluation of Neural explanation - scientific evidence
- Explanation can be tested using PET scanners which demonstrate different areas of the brain are active when exposing patients to OCD stimulus.
- Strength - uses objective, scientific evidence to support OCD has biological foundation.
Evaluation of Neural Explanation - SSRI’s not effective for all OCD patients
- Antidepressants not effective for all sufferers.
- Some patients have reported worse symptoms of OCD after taking SSRI’s.
- Weakness - questions role of serotonin in OCD, if serotonin was involved in OCD then SSRI’s should work on all patients.
Evaluation of Neural Explanation - co morbiditiy
- Many people who suffer from OCD become depressed and having 2 disorders together is called co morbidity. This depression most likely involves disruption to serotonin system and so it could be that this is disrupted in many OCD patients as they are depressed as well.
- Weakness - may be that serotonin is only involved as many patients with OCD also have depression so it is not explaining why people develop OCD.
