OCD

What is OCD and what are the two main characteristics and the types

OCD - obsessive-compulsive disorder

It is an anxiety disorder where sufferers experience persistent / intrusive thoughts occurring as obsessions / compulsions or a combination.

Obsessions - things people think about that lead to extreme anxiety (the cognitions). They comprise forbidden or inappropriate ideas and visual images that aren't based in reality e.g. germs everywhere.

Compulsions - what people do as a result of the obsession (the behavior). They comprise intense, uncontrollable urges to repeatedly do tasks like washing hands to avoid germs. These are conducted to prevent feared events to reduce stress.

Most sufferers know that their ideas / compulsions are excessive / inappropriate but can't consciously control them resulting in higher anxiety. Obsessions and compulsions are very time and energy consuming leading to an inability to conduct everyday activities.

OCD include types

• Hygiene and contamination e.g. worrying about catching HIV or AIDS

• counting + numbers

• Hoarding + collecting

• Fear of harming others e.g. children

• Symmetrical OCD - 'just right'

What are the OCD characteristics

BEHAVIOURAL

o compulsive

o Avoidance - keeping away from trigger situations

EMOTIONAL

o Anxiety and distress - OCD is unpleasant as the excessive anxiety that accompanies obsessions and compulsions

Obsessive thoughts -> frightening -> anxiety -> compulsions -> anxiety

o accompanying depression - Anxiety is often accompanied by low mood & lack of enjoyment in activities as well as irrational guilt and other negative emotions

COGNITIVE

o Hypervigilant -> alertness on tasks & potential hazards

o obsessive thoughts

What is the first biological approach to explaining OCD

Genetic explanations

focus on whether individuals inherit a genetic predisposition to developing OCD - inherit genes from parents related to OCD.

It is polygenic not caused by one gene but several eg. Taylor found as many as 230 genes and different variations may be involved in OCD types.

Two of the genes are important:

1. SERT gene (5HTT) - it is linked to the transmitter and affects the transport of serotonin which causes low levels of serotonin associated with OCD as well as depression. eg. Ozaki - mutation of this gene was found in 2 unrelated families were 6/7 had OCD

2. COMT gene - regulates the neurotransmitteR dopamine. A variation of this gene results in high levels of dopamine which is found to be more common in OCD people

Family + Twin studies

Family studies have found if you have relatives with OCD you are more likely to develop OCD. Eg. Nestadt found that people who had 1st degree relatives were & 11.7% likely to develop OCD compared to 2.7% in the control group who had no 1st degree relatives with OCD.

Twin studies

• Monozygotic (MZ) identical twins share 100% of genes and Carey and Gottesman found that they have a concordance rate of 87% compared to dizygotic (DZ) non identical twins that share 50% genes at 47%.

  Concordance rate - The probability that a pair of individuals will both have a certain characteristic given that one has it.

Give the evaluation of genetic explanations to OCD

• Evaluation of genetic explanations - RIA

1. Research - supporting evidence

   Twin and family studies show a large amount of evidence that genetic factors play a very significant role in developing OCD. Eg. Nestadt reviewed previous twin studies & found 68% of identical twins shared OCD compared to 31% in non identical twins. This supports the link between genetics and OCD as MZ twins share 100% compared to DZ at 50%. Therefore as concordance rates and percentages are higher for MZ genetics must be important.

2. Issue - Research on twin studies suggests genetics has an influence on OCD but it doesn't support genetics being the sole cause of the disorder. This is because if OCD was entirely due to genetics, concordance rates would be 100% as they share 100% of genes but its 87%. This suggests there must be other factors that play a role in OCD eg. cognition or environment. Therefore genetic explanations alone don't offer a sufficient explanation for OCD.

3. Furthermore twin studies assume that the only difference between MZ and DZ twins is the amount of genes they share, when in fact DZ twins are likely to have different experiences as they look and sound different so concordance for OCD aren't solely due to genes - causation is difficult to establish.

   3. Alternative = environmental factors

   Evidence for genetic explanation suggests that some people may be more susceptible to OCD however it doesn't say it causes it. Environmental factors also trigger the onset of OCD. Eg. Cromer et al found more than 50% of OCD patients had a traumatic event in the past and that OCD was more severe in those with this event. Diathesis-stress model is a better explanation.

Explain the second explanation of OCD - transmitters

2. Neural explanations:

   Involve the role of neurotransmitters and abnormal brain function

Neurotransmitters:

low levels of serotonin -> obsessions/anxiety

serotonin may be removed too quickly before it has transmitted its signal resulting in abnormal transmission of mood related information which is linked to obsessive thoughts and anxiety of OCD. eg. Pigott found that antidepressant drugs - reduce symptoms of OCD by increasing serotonin

high levels of dopamine -> compulsions

high levels of dopamine text may contribute to the reward seeking aspect of compulsions. Individuals with OCD experience gratification and relief after performing their rituals which may involve dopamine pathways.

eg. Kim et al gave OCD sufferers a drug that affected their dopamine levels and found this was correlated with less compulsive behaviors

Evaluate neural explanations of OCD

Evaluation: RIA

1. Research support

   Hu compared serotonin activity in 169 OCD sufferers and 253 non-sufferers and serotonin levels were lower in OCD people.

   Soomro found SSRIs were more effective than placebos in reducing OCD symptoms.

2. Issue

• Although there is a link between neurotransmitters and OCD, otherwise no causal evidence analysis possible. OCD causes low serotonin and high dopamine rather than the other way round. Also that all SSRI patients responded to the treatment suggesting it could be down to other factors.

• No conclusions can be drawn.

3. Application

• Understanding the role of neurotransmitters has lead to developments like drug therapy treatments. SSRIs are used for OCD and reduce symptoms (soomro). This provides evidence for low serotonin levels are involved in OCD and.

Explain brain structure neural explanations for OCD

2. Abnormal brain function = 'The worry circuit'

PET scans have shown OCD sufferers have elevated levels of activity in the orbitofrontal cortex and the caudate nucleus (in basal ganglia). The OFC is known as the worry circuit. The worry circuit is these parts as well as the thalamus.

The OFC is thought to turn sensory information into thoughts and actions. When the OFC detects something is wrong it sends a 'worry signal' to the thalamus. These signals are filtered/suppressed by the caudate nucleus but if it doesn't work, it can't filter the worry signals which leads to an overactive thalamus. This means the thalamus sends out strong signals to carry out an action eg. washing hands. This leads to an overactive worry circuit which could explain why people with OCD perform compulsions repeatedly.

Evaluate the worry circuit

Evaluation - RIA (worry circuit)

1. Research - supporting

• Brain-imaging research shows changes in the orbital region and the caudate nucleus in OCD sufferers compared to healthy controls. Neurotransmitter changes in these areas reduces - Saxena & Rauch.

• These areas of the brain are linked to OCD.

2. Research

• Many neural mechanisms have been identified but these aren't always present in all OCD sufferers. Neuroimaging studies have so far failed to identify basal ganglia impairment in all OCD sufferers and some people with this brain impairment show no signs of OCD.

• Ring and Serra-Mestres

• Other factors - not just biological neural

3. Issue - causation

   Although there is evidence between abnormal brain activity and OCD - there is no causal evidence so we can't conclude an overactive worry circuit causes OCD. It is possible OCD leads to changes in brain functions.

• limited - no firm conclusions.

Explain the biological approach to treating OCD

Drug therapy

that prevents the re-absorption &/or breakdown of serotonin.

1. Drugs increase or decrease neurotransmitter levels in the brain.

   In relation to OCD drug therapy is increasing serotonin.

   SSRIs (selective serotonin reuptake inhibitor) is an antidepressant

This results in more serotonin made available in the synapse so more is received.

This improves OCD symptoms by increasing serotonin levels.

Steps in SSRIs

1. serotonin is released from the presynaptic nerve and it binds to the postsynaptic nerve receptors

2. instead of by reabsorption enzymes breaking down excess serotonin - SSRI prevents this as an inhibitor.

3. This increases the no. of serotonin available to receive at receptor cells.

Fluoxetine is a SSRI

If they are proven in effective the dose is increased or multiple drug relapse - some people responddifferently to different drugs

Other drug treatments are Tricyclics - more severe side effects and SNRI - increase both serotonin and noradrenaline

Explain the evaluation of treatment of OCD

1. Effectiveness

   Research support eg. Soomro reviewed 17 studies comparing SSRIs to placebo and found they were far more effective in reducing OCD symptoms, especially between 6-12 weeks of using treatment.

   good short term treatment

2. Appropriateness

   common side effects - loss of appetite, loss of sex drive, irritability, sleep disturbance + headache

   if these are severe the person may stop treatment which would result in not effective.

   SSRIs may also increase suicidal thoughts if they occur in younger people.

3. Appropriateness

   not appropriate long term.

   eg. Cromer et al - OCD is linked to trauma so while it can reduce ST symptoms it isn't treating the underlying cause.

   CBT as well

   Maybe why relapsing of drugs after stopping is common.