OCD Flashcards
what is OCD?
A condition characterised by obsessions and/or compulsive behaviour. obsessions are cognitive whereas compulsions are behavioural
What are the different types of OCD?
-OCD
-Trichotillomania- obsessive hair pulling
-Hoarding disorder-compulsive gathering of possessions and inability to part with objects
-excoriation disorder -compulsive skin-picking
what are the behavioural characteristics?
compulsions are repetitive-suffered feel compelled to repeat a behaviour
compulsions reduce anxiety-the compulsions are done in response to general anxiety
avoidance-ppl may choose to avoid the anxiety inducing situations that cause the compulsions
What are the emotional characteristics?
anxiety and distress- powerful anxiety accompanies both obsessions and compulsions-the obsessive thoughts are often frightening, and the anxiety that comes with this can be overwhelming
accompanying depression- the anxiety can result in low mood and loss of pleasure in everyday activities because they are interrupted by obsessive thoughts and compulsions
Guilt and disgust- guilt over minor moral issues or disgust towards something external like dirt or the self.
What are the cognitive characterises?
obsessive thoughts-for 95% of sufferers obsessive thoughts are a major feature of the condition. these vary from person to person but are always unpleasant
Cognitive coping strategies- sufferers come up with methods to deal with the obsessive thoughts-cause the compulsions
insight into extreme anxiety-ppl are aware that their obsessions and compulsions are not rational.
What is needed for a diagnoses?
What are the two Biological explanations for OCD?
Genetic
neural
What is the genetic explanation for OCD?
genes make up
What is diathesis-stress model?
genetic mutations in the COMPT and SERT genes may lead to a vulnerability to OCD, other factors (stressors) need to be present in order for the condition to manifest itself.
What is the study into genes and OCD?
Lewis observed that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD.
this suggests that OCD runs in families, although what is passed on from one generation to the next is a vulnerability to OCD not the certainty of OCD.
What is a family and twin study into OCD and genes?
Nesdt et al found that first degree relatives of OCD sufferers had an 11.7% chance of developing the disorder compared to a 2.7% risk in first degree relatives without OCD.
twin studies involve a comparison between identical twins (monozygotic) and non-identicle (dizygotic)
MZ twins share 100% of their genes and DZ only share 50% so if genes do play a role in developing OCD we would expect to find a higher concordance rate for MZ than DZ.
Carey and Gottesman found MZ twins had a concordance rate of 87% for obsessive symptoms and features compared to 47% for DZ twins.
What is a candidate gene?
genes that give someone a vulnerability to OCD
Why is OCD polygenetic?
not caused by one singular gene but instead by a combination of genetic variations that together significantly increase vulnerability.
Taylor suggests that as many as 230 genes may be involved in the condition and perhaps different genetic variations contribute to different types of OCD.
What is the COMPT gene?
regulates the neurotransmitter dopamine.
may be involved in the onset of OCD as one variation of the gene results in an increase in levels of dopamine, this version is common in OCD patients.
What is the SERT gene?
linked to serotonin and affects it’s transportation.
transportation issues cause lower levels of serotonin to be active in the brain and are associated with OCD.
Ozaki published results from a study of two unrelated families who both had mutations of the SERT gene. It coincided with 6 out of 7 family members having OCD.
What is a strength of the genetic explanation?
P-a strength of the genetic explanation is that there is substantial evidence from family and twin studies that supports the role of genes in the onset of OCD
E-For example, Nestdat et al reviewed previous twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non-denticle twins. This study supports the link between genetics and OCD as MZ twins share 100% of their genes and DZ twins share 50% of their genes therefore as concordance rates and percentages are higher for MZ twins.
C-this shows that genetics must play a role in developing OCD
What is a limitation of the genetic explanation?
p-a limitation of the genetic explanation is that there is no conclusive evidence to suggest that genes are the only thing that cause OCD. It seems that environmental factors also play a part.
E-For example, Cromer et al found that over half the OCD patients in their sample had a traumatic event in their past, and that OCD was more sever in those with more than one trauma.
C-This suggests that an interactionist approach to explaining OCD would be more appropriate
what does the neural explanation for OCD include?
biochemical causes
neurophysiological causes
What are the two neurotransmitters that play a role in OCD?
dopamine
serotonin
What does serotonin have to do with OCD?
if a person has low levels of serotonin than normal transmission of mood-relevant information does not take place which means mood, and sometimes other mental processes, are affected
for example, if someone with OCD experiences low mood then they might become edgier and more hyperaware than usual, resulting in an increase of OCD behaviours
What does Dopamine have to do with OCD?
dopamine is thought to influence concentration which could explain why OCD individuals experience an inability to stop focussing on obsessive thoughts and repetitive behaviours.
What is co-morbidity?
where two or more disorders are likely to be present together
Which parts of the brain show abnormal brain circuits in those with OCD?
basal ganglia-caudate nucleus
orbitofrontal cortex
What is the basal ganglia?
a bunch is a cluster of neurones at the base of the forebrain-involved in multiple processes, including the coordination of movement.
paitients who suffer head injuries in this spot often develop OCD-like symptoms
What is the orbitofrontal cortex?
A region which converts sensory information into thoughts and actions
PET scans have found higher levels of activity in this part of the brain in OCD patients when asked to hold asked to hold a trigger item for their OCD.
What is the ‘worry circuit’
the orbitofrontal cortex sends a message of panic to the caudate nucleus
a normal brain decides whether the issue is important or not and if it is then it gets passed on to the thalamus to take action.
if the issue isn’t important or has been dealt with then it will filter out ending the circuit.
however, in the brain of an OCD sufferer, the caudate nucleus does not work correctly and sends the potentially faulty message of panic to the thalamus which then sends strong signals back to the OFC which carries out the action.
this will keep repeating on loop which is why someone with OCD performs compulsions which are repetitive rituals.
What is a strength of the neural explanation?
P-A strength of the neural explanation is the research that supports it.
E- For example, a review of brain imaging research shows elevated activity in the orbital region and the candidate nucleus has been found consistently in OCD patients compared to healthy controls. After treatment, activity in these brain areas reduces to a level comparable to that of controls as found by Saxon and Rauch.
C-This supports the neurophysiological explanation as it shows that these areas of the brain are linked with OCD.
What is a limitation of the neural explanation?
P-a limitation of the neural explanation is that it’s difficult to establish whether low levels of serotonin actually cause OCD, are an effect of having a disorder or are merely associated with the disorder.
E-Causation cannot be inferred as only associations have been identified from the research conducted
C-therefore, the biochemical explanation is limited as no firm conclusions can be made as to whether it does cause OCD.
