OCD

• what is OCD


  OCD is an anxiety disorder which is comprised of obsessions (intrusive thoughts) and compulsions (ritual bahviours)
• what are obsessions and compulsions

  obsessions = usually forbidden/inappropriate and intrusive thoughts that aren't based on reality

  compulsions = uncontrollable urges to repetitively carry out behaviours to reduce anxiety
• what are the behavioural characteristics of OCD

  Compulsions - repeat behaviours as a coping response

  Avoidance- reduce anxiety by removing triggering situations

  Social impairment- high anxiety leads to difficulty with meaningful relationship.
• what are the emotional characteristics of OCD

  extreme anxiety - caused by persistent forbidden thoughts

  distress - the thoughts cannot be controlled = stress

  depression - lack of enjoyment and low mood
• what are the cognitive characteristics of OCD

  selective attention - focused on anxiety generated stimuli

  obsessive thinking - reoccurring unpleasant thoughts

  realisation of inappropriateness - can't consciously control it
• what is the biological explanation of OCD


  also known as the medical model, it sees mental illness as caused by abnormal biological processes
• what are the 2 biological explanations for OCD

  - genetic explanation

  - neural explanation (abnormal brain activity)
• what is the genetic explanation

  argues OCD is caused by inheritance and genetic transmission from biological parent to child
• what is one gene that may be linked with OCD

  the SERT gene which affects serotonin transport
• what are the names for identical and non-identical twins

  identical = monozygotic

  non-identical = dizygotic
• what does concordance rates mean

  the percentage of pairs where both individuals share a certain characteristic in a sample of identical and non-identical twins
• what is a strength of the genetic theory involving twin concordance rates

  + research evidence from concordance rates to support OCD being caused by genes, MZ twins = 68% and DZ = 31%, MZ rate was more than double DZ suggests that genes are a cause as MZ share 100% genetics

  HOWEVER not 100% so not solely caused by genes

  FURTHERMORE high MZ could be due to a similar environment when growing up
• what is a strength of the genetic theory involving SERT gene

  + research evidence examining specific genes linked with OCD, researchers examined families genetics where 6/7 had OCD: they found a mutation in the SERT gene in the members with OCD, suggesting it may cause OCD

  HOWEVER this could be correlational as it's not proven that it causes OCD, as it's unethical to test
• what is another strength of the genetic theory

  + practical applications to understanding the genetic basis of OCD, early identification of those at risk can be monitored to see if OCD is caused, this shows the theory can be used to diagnose the disorder through genetic testing and can even help to prevent it

  HOWEVER, a self fulfilling prophecy can occur and it can shape the child to have OCD
• what is the neural explanation

  that OCD is caused by abnormalities in the brain, that is because of abnormal levels of neurotransmitters
• what are the 7 features involved in synaptic transmission

  - electrical impulse

  - pre-synaptic neuron

  - neurotransmitters

  - vesicle

  - synapse

  - receptor

  - post-synaptic neuron
• explain synaptic transmission


  an electrical signal travels down the pre-synaptic neuron, this triggers the release of neurotransmitters into the synapse.

  neurotransmitters are released from the vesicle and travel across the synapse where they bind to receptor sites on the post-synaptic neuron: the signal is either stopped or continued depending on the type of neurotransmitter
• what are the 2 types of neurotransmitter

  excitatory = fires a signal when bound

  inhibitory = prevents a signal from continuing when bound
• where are high levels of activity in people with OCD

  in the orbitofrontal cortex of the brain
• what is the role of the orbitofrontal cortex

  logical thinking and decision making
• why might high levels of activity be caused

  low levels of neurotransmitters like serotonin:

  serotonin is an inhibitory neurotransmitter so if there are low levels then the post-synaptic neuron will keep firing signals
• what are the 2 treatments for OCD

  - SSRI

  - Bz's
• what does SSRI stand for

  selective serotonin reuptake inhibitor
• what do SSRI's do

  they block the reuptake of serotonin to increase levels in the synapse to bind again to receptors: this lowers activity levels in the brain because serotonin is inhibitory
• what is reuptake


  after the neurotransmitters bind to the receptors and transmit their message, they release back into the synapse - some are taken back into the pre-synaptic neuron and put into vesicles ready for the next signal
• what do Bz's stand for

  benzodiazepines
• what do Bz's do

  reduce anxiety by slowing down the brain by increasing activity of the neurotransmitter GABA
• how do Bz's work

  when GABA binds to receptors it opens a channel that increases the flow of negatively charged chloride ions into the neuron: the ions have an inhibitory effect, causing the person to feel relaxed (less likely a neuron will fire)
• what is a strength of drug therapy for OCD

  + compared SSRI's to placebo's for treatment, in all studies they found that SSRI's were more effective than a placebo, effective for about 70% of people

  This supports drug therapy because it proves a high rate of effectiveness at treating OCD, as it helped around 70%

  However, this wasn't effective for 30% of people so doesn't help a large proportion

  Also there is little long term data that exists to show long term benefits
• what is a weakness of drugs (potentially harmful)

  - side effects can occur

  SSRI = nausea, headaches and insomnia

  Bz's = increased aggression, long term impairment of memory

  This can be enough to make people not want to take the drugs as OCD may be preferred; it replaces symptoms of OCD with harmful side effects
• what is another weakness of drug therapy (therapy comparism)

  - ERPT (exposure & ritual prevention therapy) was compared to be as effective at preventing compulsions as drugs: if therapy and drugs work equally then why risk potential side effects

  HOWEVER drugs are less time consuming, less expensive and require less energy than therapy sessions
• what is another weakness of drug therapy (publication)

  - publication bias showing a positive outcome of antidepressant treatment, exaggerating the benefits

  Doctors may make inappropriate treatment decisions that may not be in the best interest for the patient: making the research difficult to trust
• why is there a publication bias

  drug companies want the continues success of psychotherapeutic drugs: lots of research is funded by these companies so wants to show them in a positive way