Psychopathology L11 - 13 (OCD) Flashcards
OCD definition:
Anxiety disorder characterised by anxiety that arises from both obsessions and compulsions
Obsessions:
Persistent internal thoughts
Compulsions:
Repetitive external behaviours as a response to obsessions (however some may do this without obsessions)
Behavioural characteristics of OCD:
- Compulsions –> feeling that smth dreadful will happen if they do not
- Hinder everyday functioning
- Avoidance –> may attempt to reduce anxiety by avoiding situations that may trigger it
- Repetitive
- Social impairment –> anxiety levels may prevent formation of interpersonal relationships
Emotional characteristics of OCD:
- Anxiety + distress
- Accompanying depression
- Guilt + disgust –> Irrational guilt over minor issues
Cognitive characteristics of OCD:
- Realisation of inappropriateness
- Obsessions –> ideas, doubts, impulses + images
- Attention bias –> hyper-vigilant w/ more attention to stimuli
- Recognised as self-generated –> understanding that obsessions are self-thought
What are the two biological explanations for OCD?
- Genetic
- Neural
Why may OCD be inherited by sufferers and how is this usually investigated by psychologists?
- May have genetic predisposition/vulnerability
- Family/Twin studies are used
What has OCD been classed as, what does this mean and what are these responsible genes known as?
- Polygenic –> multiple genes are responsible for the disorder
- Candidate genes
How does the COMT gene cause OCD and what are its effects on the body?
- Found to be more common in OCD patients
- Regulates production of neurotransmitter dopamine
- High levels of dopamine are responsible for drive, motivation and aggression
What does the SERT gene stand for, how does it cause OCD and what are its effects on the body?
- Serotonin Transport gene
- Results in low levels of serotonin
- This means a low mood and depressive symptoms
What chromosome is the SERT gene on and what issue in the gene causes poorly regulated levels?
- Chromosome 17
- A mutation
What research support shows that it is a mutation in the SERT gene that causes OCD?
- Osaki (2003) found that 6/7 family members who had OCD had this mutated gene
- The low levels of serotonin as a result may also account for accompanying depression
List the strengths of the genetic explanation for OCD
Research support:
- Nestadt (2000) found that people who had first-degree relatives with OCD were x5 more likely to get the illness
- Billett (1998) found from a meta-analysis of 14 twin studies that OCD is 2x more likely to be concordant with monozygotic twins than dizygotic twins
- Beekman and Cath (2005)
What was Beekman and Cath’s study (2005) and what were the findings?
- Meta- analysis of 10,034 twin studies, comparing MZ and DZ twins
- OCD patients had been diagnosed by older criteria
- Studies where patients had been diagnosed with DSM criteria were also examined
- In children, OCD is transmitted genetically and genetic influence rate is from 45 - 65%
- In adults, OCD is transmitted genetically and genetic influence rate is from 27 - 47%
- Therefore OCD is transmitted genetically but is more apparent in children than adults
What are the limitations of Beekman and Cath’s research?
- Maj of twin studies were not performed in controlled conditions, which questions objectivity and validity of results
- Gene mapping (comparing DNA of twins w/ OCD and w/out) was not considered, which would be needed to make results more valid
List the weaknesses of the genetic explanation
- Concordance rate for OCD is not 100%, therefore it is not entirely caused by genetics. Other factors eg environmental/psychological may be involved
- Polygenic so it could be that it is only a predisposing factor rather than one responsible gene.
- Cause is very complex as it is also genetically linked to other illnesses eg Tourette’s + Autism
- Behavioural approach contradicts biological approach, as all behaviour can be learnt (classical + operant conditioning). The foremost has a lot of support and OCD is often treated w/ behavioural therapies
- Diathesis stress model argues the opposite, that OCD can be caused by genes but also a trigger in the environment
How do high levels of dopamine and low levels of serotonin affect parts of the brain (which parts?) respectively?
- Over activity in basal ganglia area in frontal lobes
- Malfunctioning in caudate nucleus in frontal lobes
Where in the brain is the basal ganglia, what is this responsible for and how does its malfunction lead to symptoms of OCD?
- Orbital frontal cortex
- Responsible for motor functions, habit learning, cognition + emotion
- Malfunction results in repetitive motor functions
What are the strengths of the neural explanation for OCD?
- Research support
What are the weaknesses of the neural explanation?
- Cause and effect is unclear –> high levels of dopamine and low levels of serotonin may actually be an effect of OCD, not the cause
- Unclear whether low levels of serotonin cause OCD, depression or both as they are co-morbid
- Not enough research evidence to show high levels of dopamine directly cause OCD –> they also cause bipolar depression and schizophrenia
What research support on animals shows that enhanced dopamine levels can induce OCD?
High does of drugs used on animals showed that dopamine levels were enhanced, which induced movements that resembled compulsive and repetitive behaviour. This is similar to OCD sufferers.
What research was conducted in 2000 that showed high levels of dopamine were possibly a cause for OCD?
- Ciccerone (2000) found low doses of drug Risperidone helped lower levels of dopamine and alleviate some symptoms
- Therefore high levels of dopamine may be a cause for OCD
What research was conducted in 2007 that showed an abnormality in brain structure in OCD sufferers?
- Menzies (2007) studied MRI scans in OCD patients and their immediate family and compared them to healthy controls
- OCD patients and their family had an unusual neuroanatomy and reduced grey matter in key regions of the brain
- Abnormal brain structure, causing abnormal levels of neurotransmitters, could be inherited via genes therefore supporting the neural explanation
