Psychopathology - OCD Flashcards
What is the genetic explanation of OCD?
Genes come in different forms (alleles) these could be the main cause of OCD. OCD might be inherited hence sufferers may have a genetic vulnerability or genetic predisposition. Psychologists often use family or twin studies to investigate genetics. OCD has been classed as polygenic where many genes might be responsible, these are known as candidate genes
The COMT gene:
- The COMT gene causes OCD by regulating the production of the neurotransmitter dopamine where high levels are associated with OCD dopamine is responsible for drive, motivation and aggression. The COMT gene has been found to be more common in OCD patients.
The SERT gene (serotonin transport gene):
- This gene affects transportation of serotonin, therefore resulting in low levels of serotonin which produces low mood and depressive symptoms
- Individuals have the SERT gene on chromosome 17. A mutation in this gene may cause OCD.
- Ozaki (2003), found evidence that 6/7 family members who had OCD had a mutation in the SERT gene. This mutation, then causes low levels of serotonin to be produced. There seems to be a link with OCD and depression. Therefore OCD does seem to have a genetic basis.
What are the strengths of the genetic explanations for OCD
- One strength of this model is that Nestadt (2000) supports the genetic explanation for OCD as he found that people who had a first-degree relative who already had OCD five times more likely to also get the illness. This supports the idea that OCD is transmitted genetically.
- Another strength of this model is that Billett (1998) supports the idea that OCD is transmitted genetically because he found from a meta analysis of 14 twin studies that OCD is 2x more likely to be concordant in identical monozygotic twins, rather than dizygotic nonidentical twins therefore supporting the idea that OCD is transmitted by genetics.
Describe the research related to genetic explanation of OCD
- research was done by Beekman and Cath into genetics and OCD (2005)
- A meta analysis was conducted of twin studies and OCD
– Monozygous twins were compared with dizygous twins - The psychologists also examined studies whereby OCD patients had been diagnosed using DSM criteria
– 10034 twin were studied overall and the results found that in children OCD is inherited via genes, and genetic influence ranges from 45 to 65%. Whereas in adults, OCD is inherited via genes, and the genetic influence ranges from 27 to 47%. - The conclusion was that OCD is transmitted genetically, and this was more apparent when examining children rather than adults.
What does ICD and DSM stand for?
- ICD: international classification of diseases is a classification system for all physical and mental disease is produced by the world health organisation (WHO)
- DSM: the diagnostic and statistical manual of mental disorders is the handbook used by healthcare professionals in the US and much of the world as the authoritative guide to the diagnosis of mental disorders
Evaluate the research surrounding the genetic explanation for OCD (3p)
- by Beekman and Cath (2005)
- this research can be criticised because the majority of the twin studies were not performed in controlled conditions. Therefore the data is not very objective of scientific and this might affect the validity and reliability of the results gain from this research. We can question the idea that OCD is genetic.
- Another weakness of this research is that the gene mapping was not taken into consideration when looking at whether OCD is genetic. Gene mapping would have looked closely at the DNA of the twins that had OCD and would compare this with twins that did not have OCD, and this comparison would make the results more valid and robust.
- One strength of this research is that the amount of patients that were studied overall can provide a very comprehensive and complete statistic for genetic influence ranges as twins, children and adults were all studied.
What is the neural explanation of OCD?
Dopamine:
- Dopamine is a neurotransmitter that affect the mood and might be a cause of OCD. The frontal lobes in the brain have been linked to dopamine activity.
- OCD sufferers have high levels of dopamine
- Research conducted on animals has found that high doses of drugs produce movements resembling compulsive behaviour similar to what OCD sufferers would experience
- Hi, dopamine levels have also been linked to overactivity in the basal ganglia area in the brain which controls motor functioning and learning.
Serotonin:
- Serotonin is a neurotransmitter affecting mood, and it might be the cause of OCD
- The frontal lobes in the brain have been linked to serotonin activity
- OCD sufferers tend to have low levels of serotonin, which can cause depressive like symptoms and obsessive thoughts. This is why many OCD sufferers are depressed.
- Serotonin plays a key role in operating the caudate nucleus in the brain, and it seems low levels of serotonin can cause this to malfunction.
Where are the frontal lobes located. What are they responsible for?
- located in the brain right at the front
- responsible for higher cognitive functions like memory, emotions, impulse control, problem solving, and motor function
Where is the caudate nucleus located? What function does it perform?
- located deep inside the brain near the thalamus
- responsible for: learning, memory, reward, motivation, movement
Give the strengths of the neural explanation of ocd (dopamine/serotonin)
- One advantage of this theory is that there has been a lot of research support to stage that neurotransmitters do cause OCD. Anti-depressant drugs, increase serotonin levels in OCD patients which leads to a reduction in symptoms. Therefore evidence suggests low levels of serotonin cause OCD.
- An advantage is that research conducted by Ciccerone (2000) supports the neural explanation because by giving OCD patients low doses of the drug Risperidone dopamine levels were lowered, and some symptoms of OCD were alleviated. Hence, high levels of dopamine could be a cause of OCD.
- A strength; Menzies (2007) produced evidence that supported genetic link to abnormal levels of neurotransmitters. MRI scans were studied in OCD patience and immediate family members these within compared to healthy controls. OCD patients plus family had reduced grey matter in here regions of the brain and had unusual neuroanatomy. Hence, OCD could be caused by abnormal brain structure, inherited via genes
Describe the study which supports the neural explanation of ocd. (Neuroanatomy by Jenike and Rauch)
(Neuroanatomy by Jenike and Rauch)
- There may be a relationship between OCD, been caused by some type of brain damage possibly caused by a virus. Brain damage may cause short-term memory, leading to person doubting whether they have performed an action. This is a sypmptom of OCD resulting in repetitive behaviour (compulsions) like checking the door is locked.
- OCD patients were studied using PET scans (position emission tomography). They were shown an image of something dirty. If they had a cleaning obsession, evidence found frontal lobes, and basal ganglia were most active compared to non-OCD sufferers
- Basal ganglia seems to malfunction in OCD sufferers: a series of interconnected brain structures that are at the front of the brain near the orbital frontal cortex, which also seems to be overactive in OCD patients. Basal ganglia is responsible for control of voluntary motor movements, procedural, learning, habit, learning, eye movements, cognition, emotion. Hence, an overactive basal ganglia can lead to repetitive motor functions
- Patient who have Tourette’s syndrome also seem to suffer with overactive basal ganglia
- Further research shows that OCD sufferers may have damage to the frontal cortex of the brain which is involved in selecting, controlling and inhibiting behaviour, which OCD patients struggle with
What is a PET scan? How does it work?
Positron emission tomography (PET) scans produce detailed 3D images of inside the body. You usually ingest a radiotracer and this travels around the body. It will be later detected by the scanner and will help to highlight areas
What is Tourette’s syndrome?
This is a condition of the nervous system causing people to have “tics” and these can be movements gestures or sounds. They may repeat these and have no control over them
Evaluate the neural explanations of ocd in relation to virus/brain
- One problem with this neural explanation is cause-and-effect
- A strength of this neural explanation is that it uses PET scanning
- The strength is that the psychologist Rapaport (1990), found supporting evidence about neural cases of OCD. An epidermic occurring in Europe between 19 16–1918 called “the Great sleeping sickness. “this was a widespread viral brain infection and it was found that after this epidemic there was a major rise in the number of OCD cases reported maybe because the viral infection cause damage or brain abnormality, which contributed to the development of OCD.
- One weakness of this research is that it was conducted a very long time ago and therefore may not have temporal validity and the validity of the findings can also be questioned because it is uncertain whether scientific methods were used
What is the biological approach to treating OCD? What are the two types of drugs used?
Drug therapy:
- taking antidepressants, for example, SSRI drugs (selective serotonin, reuptake, inhibitors) Some examples of these would be Prozac and fluoxetine.
- Benzodiazepines are also used. Examples would be Valium and Xanax.
Explain in detail SSRI drugs
- Low levels of serotonin are associated with OCD and depression. Therefore, these drugs into prevent the re-uptake of serotonin and prolong its activity in the synapse mean in the person will feel less anxious and have higher level of serotonin available.
- Low levels of serotonin are implicated in the “worry circuit “whereby damage to caudate nucleus in brain fails to suppress minor worry signals. A message is sent to the orbital, frontal, cortex and worrying and anxiety get worse.
- Hence drugs given to OCD patients will increase serotonin levels and help regulate mood and reduce anxiety levels, the worry circuit will also be normalised and reduced, high levels of serotonin provided by SSRI drugs, help orbitofrontal cortex to function at normal levels
- SSRI, drugs, help, stabilise moods and emotions, plus improve memory, which would help produce compulsive behaviour and checking