OCD Flashcards
What is OCD?
A condition characterised by obsessive or compulsive behaviours.
What are the behavioural characteristics of OCD?
Compulsions - to reduce anxiety, repetitive.
Avoidance.
What is an example of a compulsive behaviour and why may it be carried out?
Handwashing - as response to an obsessive fear of germs.
What is an example of avoidance behaviour?
Sufferers that wash compulsively may avoid contact with germs.
What are the emotional characteristics of OCD?
Anxiety and distress - powerful anxiety that accompanies the compulsive behaviour.
Guilt and disgust.
Accompanying depression - low mood and lack of enjoyment in activities.
What are the cognitive characteristics of OCD?
Obsessive thoughts.
Insight into excessive anxiety.
Cognitive strategies to deal with obsessions.
What are the 2 biological explanations for OCD?
Genetic
Neural
What did Lewis find that supports the genetic explanation?
That 37% of patients with OCD also had a parent with OCD, and 21% had a sibling with OCD.
Explain candidate genes.
Researchers have identified genes, which create a genetic vulnerability for OCD.
These genes are involved in regulating the production of serotonin.
Define polygenic.
OCD is not caused by one single gene but by several.
Define aetiologically heterogenous.
Why is OCD aetiologically heterogenous?
Aetiologically heterogenous - many causes.
As there are different complex forms of OCD it suggests that there are different genes involved in the cause of each type of OCD.
State 1 strength of the genetic explanation.
Good support evidence through twin studies - research has shown that 68% of identical twins shared OCD as opposed to 31% of MZ twins.
State 2 criticisms of the genetic explanation.
Too many candidate genes - the genetic explanation provides little predictive value as we can’t pin down just one single gene for causation.
Environmental factors - Cromer et al. found that over half the OCD patients in their sample had experienced a traumatic event (potentially triggering the OCD).
Explain the role of serotonin in the neural explanation.
The OCD individual may have low levels of serotonin and therefore normal transmission of mood-relevant information does not take place and consequently, mood and sometimes mental processes are affected.
Explain the role of decision making in the neural explanation.
Some OCD cases (e.g. hoarding) are associated with impaired decision making.
This in turn, may be associated with abnormal functioning of the lateral (side bits) of the frontal lobes - responsible for decision making and logical thinking.
Also evidence to suggest that the parahippocampal gyrus associated with processing unpleasant thoughts, functions abnormally in OCD.
State a strength of the neural explanation.
Supporting evidence - some antidepressants that work purely on the serotonin system, increasing levels of the neurotransmitter, have shown effectiveness at reducing the symptoms of OCD.
Also, OCD symptoms coincide with symptoms present in Parkinson’s disease (biological basis) - suggesting that OCD itself is biological in origin.
State 2 criticisms of the neural explanation.
Depression is often co-morbid with OCD - disruption of serotonin levels is also present in depressed people so we cannot be sure whether the causes of OCD are due to disruption of serotonin levels or whether the disruption was caused by the depression.
Neurotransmitters - unclear whether disrupted levels of neurotransmitters caused OCD or whether OCD caused the disruption of neurotransmitters.
What are SSRI’s?
Antidepressants.
Explain synaptic transmission for serotonin.
Serotonin is released by presynaptic neurons and travels across the synapse.
The neurotransmitter chemically conveys the signal from the presynaptic neuron to the post-synaptic neuron.
It is then reabsorbed by the post-synaptic neuron where it is broken down and then re-used.
How do SSRI’s work?
They prevent the re-absorbtion and break down of serotonin to increase the levels of it in the synapse to continue to stimulate the post-synaptic neuron.
What is the typical daily dosage of Fluoxetine?
20mg (although may be increased if it is not benefitting the patient).
What else can SSRI’s be combined with?
CBT
Why is a combination of SSRI’s and CBT useful?
SSRI’s - reduce the patients emotional symptoms (feeling anxious or depressed). Also allows the patient to engage more effectively in the CBT.
CBT - target reason for OCD.
What are the alternatives to SSRI’s?
Tricyclics - eg clomipramine (more side effects the SSRI’s).
SNRI’s - increase levels of serotonin and non-adrenaline.
State 2 strengths of drug therapy treatment.
- Effective at tackling OCD symptoms - Soomro et al. reviewed studies comparing SSRI’s to placebos and concluded that all 17 studies reviewed showed significant better results for the SSRI’s than the placebo. - typically symptoms reduce for 70% of patients, the remaing 30% combine treatment with CBT or try alternative drugs.
- Cost effective and non-disruptive
State a criticism of drug therapy treatment.
Side effects - indigestion, blurred vision and loss of sex drive.
