OCD

characteristics of OCD

OCD is classed as an anxiety disorder. Prevalence is 1.3% in the UK It is characterised by two main types of symptom. These are:

• Obsessions - these are persistent and recurrent thoughts or impulses which cause anxiety

• Compulsions - these are repetitive behaviours or mental acts that the person feels driven to perform in response to an obsession. Carrying out the compulsion usually lowers the anxiety caused by the obsession.

Frequently, obsessions and compulsions are related. For example, fear of germs or contamination (the obsession) might be accompanied by excessive and ritualistic washing and cleanliness behaviour (the compulsion). However, the compulsion does not always follow logically from the obsession e.g. a patient who turns the lights on and off a set number of times (the compulsion) to avoid disastrous things happening (the obsession).

emotional characteristics of OCD

Obsessions and compulsions are a source of anxiety and distress
Sufferers are aware that their behaviour is excessive and this causes feelings of embarrassment and shame.

cognitive characteristics of OCD

• Obsessions are the cognitive characteristic. These are recurrent, intrusive thoughts or impulses. They may be frightening or embarrassing.

• These are not simply excessive worries about everyday problems; they are uncontrollable and excessive.

• The person recognises that the obsessions are a product of their own mind and unreasonable.

behavioural characteristics of OCD

• Compulsions are the behavioural characteristics. Behaviours are performed to reduce the anxiety created by obsessions. They are repetitive and can be acts like hand washing, checking and counting.
  Patients feel that they must perform these actions otherwise something dreadful might happen.

• Sometimes the behaviours are not connected in a realistic way to what they are trying to prevent, e.g. turns the lights on and off a set number of times to avoid disastrous things happening.

biological approach/explanations of OCD - genetic factors

Genetic factors- people can inherit a predisposition for mental illness that it passed from one generation to the next in the DNA. If abnormality is genetic we would expect relatives who share genes to also share psychological abnormalities

biological approach/explanations of OCD - neural explanations

Neural explanations - The development of mental disorders is explained in terms of an imbalance in the concentration of neurotransmitters, the chemical messengers that nerve cells use to communicate with each other. The levels of a particular neurotransmitter may be too high or too low and therefore affect brain functioning. Neuroanatomy - Physical damage to brain structures that may occur during birth or due to an accident or the brain may malfunction due to neurotransmitter levels.

methods of investigating role of genes in abnormality - family studies

Family studies can be used to investigate the role of genes in abnormality.

Biological relatives share genes and the closer their biological relationship the greater the number of genes they share. 1 degree relatives such as parent & child or siblings share 50% of their genes, grandparents and their grandchildren share 25% of their genes etc. If abnormality is genetic then we would expect if one member of a family has a disorder then other members of the same family should also have the disorder.

However, the problem is that as well as sharing genes biological relatives also share the same environment so it is difficult to separate out the effect of genes and environment.

methods of investigating role of genes in abnormality - twin studies

Twin studies are thought to reduce the problems of separating out genes and environment. In twin studies researchers compare identical (MZ- monozygotic) twins and non-identical (DZ- dizygotic) twins. MZ twins share 100% of their genes whereas DZ twins only share 50% of their genes. Both sets of twins share the same environment. Therefore if MZ twins are more similar than DZ twins it suggests a role of genes whereas if both sets of twins are similar it suggests a larger role for the environment. Researchers look at the number of twins that both have the disorder. This is known as the concordance rate.

genetic explanation of OCD

The basic idea is that individuals inherit specific genes from their parents that are related to the onset of OCD. Research suggests that the COMT gene may contribute to OCD; this gene regulates the production of the neurotransmitter dopamine. One form of the COMT gene has been found to be more common in OCD patients than people without the disorder. This gene variation produces lower activity of the COMT gene and causes higher levels of dopamine. Another possible candidate gene is the SERT gene. This gene affects the transport of serotonin, creating lower levels of this neurotransmitter. Taylor (2013) found evidence that there might be up to 230 different genes involved in OCD. This suggests that OCD may be polygenic. This means that OCD is not caused by a single gene but there are several genes involved.

evidence for generic basis of OCD - family studies

Family studies have shown that relatives of OCD sufferers have a greater tendency to suffer from OCD and anxiety related problems themselves. This indicates a potential genetic contribution to OCD. Nestadt et al. (2000) identified patients with OCD and their first-degree relatives and compared them with control patients without mental illness and their first-degree relatives. Found that first-degree relatives (parents, siblings, and children) of OCD sufferers had a 5 times greater risk of developing the disorder compared to the control group.

evidence for generic basis of OCD - twin studies

Twin studies have also been used to investigate the role of genetics in OCD: this is because identical twins (monozygotic twins) are genetically identical. Therefore, if OCD is genetic, when one MZ twin develops it so should the other. Nestadt et al. (2010) reviewed previous twin studies and found that if one MZ twin had OCD then there was a 68% chance that the other twin would also develop it. DZ twins share only half their genes, if one DZ twin had OCD there was only a 31% chance of the other twin also suffering.

evaluation for evidence for genetic basis of OCD

However, identical twins (MZs) may have more similar environments than DZ twins as they may be treated more similarly as they look identical. Therefore, the similar environment may be the reason MZ twins are more similar rather than genes. This undermines the theory behind the MZ & DZ% comparisons as it may be environment rather than genes that can explain the difference.

neural explanation of OCD

Genes code for levels of chemicals called neurotransmitters in the brain. These chemicals transmit signals between nerves. Low serotonin and high dopamine levels have been linked to OCD. Abnormal levels of these neurotransmitters may result in abnormal brain circuits in OCD. Several areas in/linked to the frontal lobe are thought to be abnormal in people with OCD. The frontal lobe of the brain is responsible for decision making and logical thinking:

• The OFC is involved in decision making and worry about behaviour. A malfunctioning OFC would result in increased anxiety and increased planning to avoid the anxiety (obsessions).

• The thalamus is a brain area whose functions include cleaning, checking and other safety behaviours. An overactive thalamus would result in an increased motivation to clean or check for safety (compulsions).

Serotonin and dopamine are linked to these areas of the brain. Serotonin plays a key role in the functioning of the OFC, therefore abnormal levels of serotonin may cause this area to malfunction. Dopamine is also linked to this whole neural system; high levels lead to over activity.

neural explanation for OCD evaluation summary

• PET scans

• treatments

neural explanation for OCD evaluation - PET scans

Supporting evidence for the role of neural mechanisms comes from PET scans of patients with OCD taken while their symptoms are active (e.g. when a person with a germ obsession holds a dirty cloth). These scans show heighted activity of the OFC, therefore supporting that this brain region is involved in OCD

neural explanation for OCD evaluation - treatments

Treatments: A strength of the neural explanation is that it is supported by the findings that drug treatments (which increase serotonin activity) have been found to decrease OCD symptoms. Furthermore, this finding has implications for providing effective treatments for OCD. Drug treatments work on the premise that if an imbalance of neurotransmitters is the cause of mental illness then using drugs to alter neurotransmitters can be effective in treating the illnesses e.g. antidepressants raise serotonin levels and have been found to be successful in treating OCD (70% effectiveness). Therefore it suggests that low levels of serotonin was the original cause.

overall evaluation for the biological approach to OCD summary

• reductionist

• takes blame away from patient

• deterministic

overall evaluation for the biological approach to OCD - reductionist

Reductionist: A weakness of the biological model is that it is reductionist. This is because it reduces the complex causes of abnormality down to just biological causes, such as genetics. This is too simplistic as there are likely to be other causes of OCD (as MZ concordance rates are never 100%), such as the environment, our thought processes and the unconscious. Supporting this idea is evidence from Cromer et al. (2007) that over half of OCD patients in their sample had suffered from a traumatic event in their past. Alternatively, the behaviourist two-process model can be applied to OCD. Initial learning occurs through classical conditioning when a stimulus e.g. dirt is associated with anxiety. This is maintained through operant conditioning as the stimulus is avoided using compulsive behaviours to reduce the anxiety. This then causes an obsession to form.

overall evaluation for the biological approach to OCD - takes blame away from patient

Because the cause is biological, it takes the blame of the mental illness away from the patient; it isn't their fault that they are suffering. On the other hand, a cognitive approach to OCD could make the patient feel that they are to blame as it is their faulty thinking causing the disorder. However, by removing the blame you also remove control over the disorder. The patient may feel helpless as they cannot control their neurotransmitter levels and this may make them feel worse.

overall evaluation for the biological approach to OCD - deterministic

Deterministic: However, because the theory argues that the cause of OCD is biological it removes responsibility and control from the individual and may make them feel powerless. It implies that if you have the COMT/SERT gene and the neuroanatomy you will experience OCD. This means that the theory is deterministic and removes freewill from the patient. In addition this is socially sensitive a accepting a genetic cause of OCD may make parents feel guilty as they passed on the genes to the individual.

conclusion for cause of OCD

The diathesis-stress model is a better explanation of the causes behind disorders. It is likely that genetics create vulnerability (diathesis) for OCD and other disorders but other factors (stressors) affect if a condition develops and which disorder it is.

biological treatments for OCD - drugs

Drug treatments for abnormality are based on the assumption that if abnormality is caused by an imbalance in the levels of neurotransmitters, then drugs that restore the levels of neurotransmitter to the correct amount should eliminate the symptoms. There are different types of drugs to treat different abnormalities.

biological treatments for OCD - antidepressants

These are the most commonly used drugs to treat OCD. Low levels of the neurotransmitter serotonin are associated with both depression and OCD, so drugs to increase levels of serotonin are used with both mental disorders. Low levels of serotonin are linked to the function of the OFC so increasing serotonin levels may normalise the OFC and reduce the obsessions and anxiety associated with OCD.

biological treatments for OCD - selective serotonin re uptake inhibitors

SSRIs are the standard antidepressant used to tackle the symptoms of OCD. Examples of SSRIs are Prozac, Fluoxetine and Zoloft. During neurotransmission serotonin is released by the presynaptic neuron and diffuses across the synapse to bind with receptor sites on the post-synaptic neuron. Afterwards, serotonin is reabsorbed by the presynaptic neuron where it is broken down and reused SSRIs work on the transmission of serotonin in the brain by increasing serotonin levels in the synapse. They prevent the reabsorption and breakdown of serotonin by blocking reuptake pumps. This results in higher levels of serotonin at the synapse so that it can continue to stimulate the postsynaptic neuron. This compensates for the low levels of serotonin found in OCD patients. Dosage will vary according to the particular SSRI prescribed; a typical dose of Fluoxetine is 20mg, although this might be increased if it is not benefitting the patient. The drug is available in capsules or liquid. It takes three-four months of daily use for SSRIs to have much impact on OCD symptoms. If an SSRI is not effective after three-four months, the dose can be increased or it can be combined with other drugs. Alternatively, sometimes different antidepressants are tried e.g. Tricyclics. These are an older type of anti-depressant and have the same effect on the serotonin system as SSRIs. However, they have more severe side effects so they are only used for patients who do not respond to SSRIS.

drug therapy for OCD evaluation summary

• effectiveness

• appropriateness - can live normal lives

• appropriateness - side effects

• treats symptom not cause

• effectiveness of drugs

drug therapy for OCD evaluation - effectiveness

Effectiveness: A strength of drug therapy is that there is clear evidence for the effectiveness of SSRIs in reducing the severity of OCD symptoms. Soomro et al. (2009) reviewed studies comparing SSRIs to a placebo in the treatment of OCD and concluded all 17 studies showed significantly better results for SSRIs than for placebo conditions. Typically, symptoms decline for around 70% of patients taking SSRIs. Therefore, drugs can help most patients with OCD.

drug therapy for OCD evaluation - appropriateness - can live normal lives

Appropriateness: A strength of drug treatment is that it allows many people to live normal lives and greatly improves quality of life. Many people prefer drugs to receiving therapy This may be because taking medicine is a familiar activity whereas psychological treatment is more disruptive to patients, it is unfamiliar and many people feel threatened by it. However, drugs remove control from the patient and place it into the hands of the doctor whereas therapy would give them more control.

drug therapy for OCD evaluation - appropriateness - side effects

Appropriateness: A weakness of drug therapy is that some patients suffer side effects. For example, common side effects of SSRIs are nausea, headaches and insomnia. Tricyclic antidepressants have more serious side effects. For example, 1 in 10 patients will experience erection problems, tremors, and weight gain and more than 1 in 100 patients become aggressive and suffer from disruption to their heart rate. Therefore, this means that these drugs may not be appropriate for all patients.

drug therapy for OCD evaluation - treats symptom not cause

Treats the symptoms not the cause: A weakness of drug treatments is that they only treat the symptoms of the illness and not the cause. This means that when the patient stops taking the drugs the symptoms will return within a few weeks and sometimes the symptoms can be worse than the ones they were originally being treated for; consequently drugs only provide a short term solution. In comparison, psychological treatments such as CBT offer a more long term cure, and although they are more expensive the may be more cost effective in the long term.

drug therapy for OCD evaluation - effectiveness of drugs

A further weakness of drug therapy is that there are issues with the studies showing effectiveness of drugs. Some argue that the positive findings of clinical trials are a result of publication bias. This means that negative or neutral results are often not published. Even more sinister are the accusations made about research funded by the drug companies themselves. It has been found that research funded by these drug companies is more likely to find favourable results than research by other sources, and it may be that drug companies actively suppress damaging findings

economic implications os psychological research

The McCrone report (2008) estimated the direct costs of mental health in England at about 22.5 billion a year. The report comments on the use of drugs versus Psychological therapies saying the number of people receiving medication provides a much greater economic gain than psychological therapies, which may produce similar benefits compared with medication but are far more expensive'. Evidence based research on effective drug treatments is therefore important in reducing costs and helping people return to work. However, research shows that people with OCD are likely to relapse after ceasing drug therapy. Therefore, even though a Psychological therapy such as CBT might initially be more expensive than drug therapy, in the long-term it might be more economically sound to offer cognitive therapy as people would have less time off work.

clinical trials with placebo

When investigating the effectiveness of drug treatments researchers cannot just compare the improvement in patients taking the drug and patients undergoing no treatment. This is because of expectancy effects in patients. If patients are given a drug to treat their symptoms then because they think it will work, they often report an improvement in symptoms even if the drug itself does nothing. This is known as the placebo effect. It is like people who think they have been drinking alcohol acting drunk due to their expectations even if they have only drunk water. Because of this clinical trials must compare the effectiveness of a drug with a placebo (like a sugar pill that has no effect on symptoms). If patients in the drug group have a greater improvement than the placebo group then this is due to the drug rather than expectancy effects. The patient should not be aware of which condition they are in- i.e. whether they are taking the drug or the placebo or expectancy effects will return. This is known as a single blind trial. In most trials the doctors assessing the patients are also unaware of whether the patient is on the drug or placebo. This is known as double blind. This is to stop researcher expectancy affecting the results. However, there are issues with placebo trials as patients may be able to guess if they are on the placebo as they will not experience side effects.