OCD

Question 1

What is OCD?

Answer 1

OCD is classed as a type of anxiety disorder in diagnostic manuals e.g. the DSM and ICD – what are these?
The condition is characterised by obsessions and compulsions:

Question 2

What are Obsessions (internal component):

Answer 2

Persistent, recurrent, intrusive, unpleasant thoughts.

Question 3

What are compulsion (external component)?

Answer 3

Repetitive, ritualistic behaviours (generally in response to obsessions – to reduce anxiety).

Question 4

Emotional characteristics of OCD:

Answer 4

Extreme anxiety: Obsessive thoughts are unpleasant and frightening; the urge to repeat a behaviour (compulsions) causes high levels of distress.
Guilt and disgust: Sufferers experience feelings of embarrassment, shame, guilt and disgust as they know that their behaviour is excessive.

Question 5

Behavioural characteristics of OCD:

Answer 5

Compulsions are repetitive: Repeating behaviours/mental acts in response to obsessive thoughts e.g. hand-washing, checking, counting.
Hinder everyday functioning: e.g. being unable to work effectively.

Question 6

Cognitive characteristics of OCD:

Answer 6

Obsessive thoughts: Recurrent and persistent thoughts, of an intrusive and unpleasant nature; catastrophic thoughts about worst case scenarios.
Hypervigilance and selective attention: Sufferers maintain constant alertness and keep attention focused on hazards.
Insight into irrational obsessions and compulsions: Sufferers understand that they are inappropriate, but are unable to consciously control them.

Question 7

Common obsessions include:

Answer 7

Contamination e.g. germs
Perfectionism e.g. fear of not being the best
Fear of losing control e.g. hurting others

Question 8

Common compulsions include:

Answer 8

Excessive washing and cleaning e.g. hand-washing
Excessive checking e.g. that doors are locked
Mental compulsions e.g. praying, counting

Question 9

What are the two key biological explanations for OCD?

Answer 9

1) Genetic explanation:
This includes the role of the COMT gene and the SERT gene (both of which are thought to affect levels of certain key neurotransmitters if they exist in a mutated form), as well as the idea that OCD is an inherited condition.

2) Neural explanations:
This includes abnormal levels of neurotransmitters such as dopamine and serotonin AND abnormal brain circuits (the “worry circuit”).

Question 10

What is the genetic explanation for OCD?

Answer 10

It may be the case that an individual inherits a specific gene from their parents that causes the onset of OCD.

This gene may then have an effect on levels of neurotransmitters in the brain, resulting in abnormal levels and the onset of the disorder.
Research has found that a person with a family member diagnosed with OCD is around 4x more likely to develop it as someone without.

Question 11

What is the COMT gene?

Answer 11

The COMT gene is related to the production of a chemical called COMT, which is involved in the regulation of the neurotransmitter dopamine.

All genes come in different forms. This particular form of the COMT gene (a gene which we all have) has shown lower levels of activity, resulting in higher levels of dopamine (as it is not as heavily regulated).

Question 12

What is the SERT gene?

Answer 12

This gene affects the transportation of serotonin - it may be that those with a mutated variation of this gene have lower levels of serotonin.

Question 13

What is the COMT and SERT genes relation to the genetic explanations for OCD?

Answer 13

Genetic explanations for OCD suggest that individuals inherit specific genes that cause OCD. Two genes that have been linked to OCD are the COMT gene and SERT gene.
The SERT gene affects the transportation of serotonin and can cause lower levels of serotonin, which is also associated with OCD.
The COMT gene is responsible for the regulation of dopamine and low activity of the COMT gene is associated with high levels of dopamine, resulting in OCD.
It is also believed that OCD is a polygenic condition, which means that several genes areinvolved.

Question 14

What is the diathesis-stress model?

Answer 14

It may be the case that there is an interaction between GENES and the ENVIRONMENT…..
The gene may provide a genetic predisposition (vulnerability) to developing OCD;
And this is triggered by another factor, perhaps from the environment (biological or psychological) e.g. a stressor.

Question 15

What is the research evidence for the genetic explanation for OCD?

Answer 15

Groothest et al (2005)

Question 16

What is the Groothest et al (2005) procedure?

Answer 16

Grootheest et al. conducted a meta-analysis, assessing 70 years of twin studies (10,034 twin pairs across 28 studies in total) into OCD, where MZ (identical – share 100% of their genes) twins are compared against DZ (non-identical – share 50% of their genes) twins.
A meta-analysis involves combining the results from many different studies (in this case OCD studies on twins).

Question 17

What is the Groothest et al (2005) findings?

Answer 17

In children, it was found that OCD symptoms are heritable, with genetic influences ranging from 45-65%.
In adults, it was found that OCD symptoms are heritable, with genetic influences ranging from 27-47%.

Question 18

What is the Groothest et al (2005) conclusions?

Answer 18

These findings suggest that twin studies indicate a genetic component to the transmission of OCD.
Heritability of OCD appears to be greater in children than adults.

Question 19

What is the further support for the genetic explanation of OCD?

Answer 19

Nestadt et al. (2010) conducted a review of previous twin studies examining OCD. They found that 68% of identical twins (MZ) shared OCD as opposed to 31% of non-identical (DZ) twins, which suggests a very strong genetic component to OCD.
However, the fact that the concordance rate is not 100% suggests that environmental factors play a part too.

Question 20

What is the neural explanation for OCD?

Answer 20

These genetic factors may lead to abnormalities in terms of the wiring of the brain and levels of certain key neurotransmitters (chemical messengers in the brain), resulting in OCD.

As previously mentioned, there are two key neurotransmitters that are implicated in OCD:
1. Serotonin
2. Dopamine

Question 21

Where do obsessive thoughts originate from in the brain?

Answer 21

Where do obsessive thoughts originate from in the brain?
PET scans have shown that OCD sufferers can have relatively high levels of activity in the orbital frontal cortex (OFC).
The OFC is associated with higher level thought processes and the conversion of sensory information into thoughts.
This brain area is thought to help initiate activity upon receiving impulses to act, and then stop the activity when the impulse lessens.

Question 22

What is an example of obsessive thoughts originating from in the brain?

Answer 22

For example, you may experience an impulse to wash dirt from your hands and once this is done the impulse to perform the activity stops, and so too does the behaviour.

Question 23

How does abnormal brain circuits lead to compulsive behaviour?

Answer 23

However, in the case of an OCD patient, it may be the case that there is difficulty switching off these impulses, which turn into obsessions (recurring thoughts e.g. of contamination) and leads to compulsive behaviour.

Question 24

What is the caudate nucleus?

Answer 24

The caudate nucleus (located in the basal ganglia) normally suppresses worry signals from the orbital frontal cortex (OFC).

Question 25

What is the OFC?

Answer 25

In turn, the OFC send signals to the thalamus about things that are worrying, such as a potential germ hazard.

Question 26

What happens when the caudate nucleus is damaged?

Answer 26

When the caudate nucleus is damaged, it fails to suppress minor ‘worry signals’ (from the OFC) and the thalamus is alerted, which in turn sends signals back to the OFC, acting as a ‘worry circuit’ in the brain.

Question 27

Research support: neural explanation for OCD. P: Evidence for neural explanations of OCD comes from Saxena and Rauch (2000).

Answer 27

E: They reviewed studies of OCD that used PET, fMRI and MRI neuro-imaging techniques to find consistent evidence of an association between the orbital frontal cortex and OCD symptoms.
C: This suggests that specific areas and mechanisms of the brain (specifically the OFC) are involved in the disorder.

Question 28

How are serotonin and dopamine linked?

Answer 28

Serotonin and dopamine have been linked to these regions of the frontal lobes.

Question 29

What role does serotonin play in the operation of the OFC and the caudate nucleus?

Answer 29

Serotonin is thought to play a key role in the operation of the orbital frontal cortex (OFC) and the caudate nucleus. Therefore, it is feasible that abnormal levels of serotonin might cause these areas to malfunction.

Question 30

What is dopamine and what main transmitter is it of?

Answer 30

Dopamine is the main neurotransmitter of the basal ganglia, which is where the caudate nucleus is located and high levels of dopamine are thought to lead to overactivity of this region.

Question 31

Research Support: Neural Explanation. Hu (2006):
P: Evidence for the role of serotonin in OCD comes from Hu (2006) who compared serotonin activity in 169 OCD sufferers and 253 non-sufferers.

Answer 31

E: It was found that serotonin levels were lower in the OCD patients.
C: This supports the idea that low levels of serotonin are associated with the onset of OCD.

Question 32

What had animal research shown on levels of dopamine?

Answer 32

Animal research has shown that when drugs that increase levels of dopamine are administered to rats, they often display stereotyped movements that resemble compulsive checking behaviours found in patients with OCD (Szechtman et al., 1998).

Question 33

What do PET scans show in OFC in OCD patients?

Answer 33

Evidence from research using PET scans shows increased activity in the orbital frontal cortex (OFC) amongst OCD patients, for example, when a person with a germ obsession holds a dirty cloth, supporting the neural explanation.

Question 34

valuation of the Genetic Explanation for OCD:

What does the fact that there is not a 100% concordance rate between MZ twins for OCD suggest?

The fact that twin studies have not shown a 100% concordance rate suggests that OCD is not caused by genetic factors alone, there must be other possible causes (e.g. environmental).

Answer 34

Even where OCD is found to run in families, it may be learnt as well as possibly inherited, but it is difficult for research to disentangle the role of genes from the environment.
Also, where the condition is thought to run in families, it is rarely the case that specific symptoms are inherited (e.g. an obsession with dirt), which suggests that there is an environmental component to OCD in terms of the symptoms experienced.

Question 35

Evaluation of the Genetic Explanation for OCD:
What does the meta-analysis by Grootheest et al. (2005) suggest?
P: The findings of Grootheest’s meta-analysis of twin studies indicates a genetic component to the transmission of OCD.

Answer 35

E: In children, it was found that genetic influences ranged from 45-65%, whereas in adults it was found that genetic influences ranged from 27-47%.
C: The fact that the heritability of OCD appears to be greater in children than adults suggests that it is more likely to be caused by genetic factors when the onset is in childhood.

Question 36

Evaluation of the Neural Explanation for OCD: Explain why there is an issue of cause and effect with regard to the neural explanations…

Answer 36

P: We can’t say for sure that the biological factors identified (e.g. low levels of serotonin, abnormal brain circuits) are causing OCD.
E: It could be the case that they are an effect of the OCD i.e. OCD reduces serotonin activity.
C: This presents issues of cause-effect within this theory and as such reduces its validity.

Question 37

Evaluation of the Neural Explanation for OCD. Why does the fact that some anti-depressants which increase the availability of serotonin in the brain help alleviate symptoms of OCD in some people support this explanation?

Answer 37

Point: The fact that anti-depressants are used to treat OCD supports the neural explanation.
Evidence: Anti-depressants (e.g. SSRI’s) increase the availability of serotonin, which in turn have been shown to reduce the symptoms of OCD (Pigott et al., 1990).
Comment: This seems to strongly suggest that low levels of serotonin are a cause of OCD symptoms.

However, not all OCD patients respond to drugs that increase levels of serotonin, which suggests there may be more than one type of OCD, with different biological (or psychological) causes.

Question 38

What is the evolutionary explanation for OCD?

Answer 38

OCD has an adaptive survival value in that it increases vigilance and alertness e.g. to potential contamination, which could lead to infection and death.
OCD therefore helps in the avoidance of harm.
Some of the behavioural features of OCD, such as precision and hoarding, would be beneficial in hunting and foraging.

Question 39

Cognitive explanation for OCD:

Answer 39

OCD sufferers have faulty/irrational thought processes, that focus on anxiety-generating stimuli.
These faulty thought patterns could be caused by genetic factors though.

Question 40

How do we know that drug treatments can treat OCD?

Answer 40

Given the evidence that OCD is linked to abnormal levels of neurotransmitters (dopamine and serotonin), there are drug treatments to address this chemical imbalance.

Question 41

What are Anti-depressants (SSRIs) used for?

Answer 41

Low levels of serotonin are implicated in the ‘worry circuit’ (see neural explanations), so increasing levels of the neurotransmitter may normalise activity in this part of the brain.
The most commonly used drug to do this is a Selective Serotonin Reuptake Inhibitor (SSRI) e.g. Prozac, which is generally used as an anti-depressant.

Question 42

How is serotonin released into the synapse?

Answer 42

Serotonin is released into the synapse from the pre-synaptic neuron and targets receptor sites on the post-synaptic neuron.
After it has sent the message to the next neuron it is released back into the synaptic gap.
Serotonin is normally removed from the synaptic gap by reuptake sites (or transporter sites) on the pre-synaptic neuron.

Question 43

How do SSRIs block the serotonin reuptake sites?

Answer 43

SSRIs block the serotonin reuptake sites, allowing serotonin to remain active in the synapse for longer. This therefore leads to greater availability of serotonin in the synaptic space (to bind to receptor sites).

Question 44

What do Benzodiazepines do?

Answer 44

BZ’s slow down the activity of the central nervous system by enhancing the activity of a natural biochemical substance called GABA (gamma-butyric acid).

Question 45

What is GABA?

Answer 45

GABA is the body’s natural form of anxiety relief (it has a quietening effect on the brain). GABA acts by…
It reacts with special sites on receiving (post-synaptic) neurons. It locks into these receptors causing a channel to open that increases the flow of chloride ions into the neuron.
Chloride ions make it more difficult for the neuron to be stimulated by other neurotransmitters - resulting in a reduction in activity and the person feeling more relaxed.

Question 46

What are the strengths of drug therapy? P: Research suggests that drug therapy, specifically anti-depressants (SSRIs) are effective in reducing OCD symptoms (both the obsessive thoughts and compulsive behaviour).

Answer 46

E: Soomro et al. (2008) reviewed 17 studies (meta-analysis) into the use of SSRIs vs. placebo treatments on 3,097 OCD patients and found SSRIs to be more effective than placebos at reducing symptoms in the short-term, up to 3 months after treatment.
C: This therefore suggests that the patients’ symptoms improved as a result of the medication elevating levels of serotonin, as opposed to the expectation that their symptoms would improve.

Question 47

Limitations of drug therapy: P: It could be argued that drug treatments do not actually cure OCD - essentially they just reduce the symptoms to enable the individual to lead a more normal life.

Answer 47

E: …which is indicated by the fact that patients often relapse (their symptoms return) within a few weeks if medication is stopped.
C: Therefore, drugs do not deal with the root cause of OCD – they ‘paper over the cracks’ - and so are not necessarily a good long-term treatment option.
Research has shown that the most effective treatment is to combine a drug treatment with a psychological treatment e.g. CBT.

Question 48

Limitations of drug therapy. P: A limitation is the side effects that OCD patients may experience

Answer 48

E: SSRIs: Nausea, headaches, insomnia, low libido, loss of appetite.
BZs: Increased aggression, impaired memory and a risk of addiction - they should only be prescribed for a maximum of 4 weeks.

C: Therefore, it may be the case that the side effects are severe enough to outweigh the benefits of the drugs i.e. removing the symptoms of OCD.

Question 49

strengths of drug therapy: P: Drug treatments are widely used to treat OCD and are often considered more user-friendly and preferable to psychological treatments like CBT.

Answer 49

E: Drug treatments require little effort and time, and are relatively cheap in comparison to CBT, where patients are expected to attend several sessions with a therapist, discuss their thoughts and complete ‘homework’ assignments outside of the therapy sessions.

C: Therefore, they are a popular option with patients who lack the time, motivation, commitment and verbal skills needed for CBT.
Drugs can also reduce anxiety and symptoms sufficiently for CBT to be successfully introduced later.

Question 50

Limitations of drug therapy: P: Drug treatments may not in fact reduce the obsessive symptoms associated with OCD.

Answer 50

E: Instead, it may be the case that they lesson the depressive symptoms associated with OCD.

C: This therefore casts doubt on the effectiveness of drug therapy as a treatment for OCD.