OCD

What is OCD

an anxiety disorder characterised by persistent, recurrent unpleasant thoughts and repetitive, ritualistic behaviours

what are the cognitive characteristics of OCD

Obsessions which are uncontrollable and cause anxiety

Shows an awareness that obsessions are excessive

what are obsessions

recurrent intrusive thoughts, images, impulses or beliefs (usually that are inappropriate, forbidden or that something bad will happen)

what are the emotional characteristics of OCD

both obsessions and compulsions cause anxiety and distress

Sufferers realise that their behaviour is excessive and this can cause embarrassment and feelings of shame

What are the behavioural characteristics of OCD

Compulsions- ritualistic repetitive behaviours to reduce anxiety of the obsession

What are the elements of the biological explanation of OCD

Genetics, DNA, neurotransmitters, neural features

What genes are linked to OCD

there are around 230 separate ‘candidate genes’ found more frequently in those with OCD- Taylor 2013

eg the SERT gene and COMT gene

what is the impact of the COMT gene

regulates production of dopamine

the variation common in OCD patients produces lower activity of the usual COMT gene functioning leading to higher dopamine levels

what is the impact of the SERT gene

affects transportation of serotonin with variations creating lower levels of serotonin

how is serotonin linked to OCD

serotonin regulates mood

low levels of serotonin are thought to cause obsessive thoughts and low mood

due to quick removal from the synapse before it is able to transmit its signal

how is dopamine linked to OCD

high levels found in people with OCD

AO3 for Genetic explanations of OCD

Evidence comes from twin studies

The link between OCD and genes is complex

The genes related may not directly cause OCD

There is evidence from twin studies for the genetic basis of OCD

There is much evidence from twin studies and of first degree relatives

eg Nestadt found people with a first degree relative with OCD have a 5x greater risk of the illness than the general population

Billett’s meta analysis found MZ twins are more than twice as likely to develop OCS if their co-twin has the disorder than was the case for DZ twins (31% DZ 68% MZ)

this suggests a relationship between genetic factors and OCD however as concordance rates are never 100% it suggests environmental factors must play a role too

The link between OCD and genes is complex

There is not a simple link between one gene and a complex disorder like OCD. It is more likely that variations of genes increase the likelihood of OCD but environmental stressors affect if OCD develops. Cromer showed 54% of participants with OCD reported at least one traumatic life event

some people could possess faulty COMT or SERT gene variations but suffer no ill effects, suggesting there are other factors which contribute to the development of OCD, offering a diathesis- stress approach as being more appropriate

The related genes may not directly cause OCD

The behavioural/ cognitive characteristics are also found in many other disorders and conditions eg anorexia, depression etc. This symptom overlap means we cannot determine a specific gene or set of genes which are unique to OCD

Instead, the genes seem to act as a predisposing factor towards obsessive type behaviour, with environmental factors/ stressors also contributing to the development of each type of disease

AO3 for neurotransmitters linked to OCD

there is evidence from animal research of the effects of high dopamine

There is evidence based on drug treatments for the impact of low serotonin levels

there is evidence from animal research of the effects of high dopamine

High doses of drugs that enhance levels of dopamine induced stereotyped movements resembling compulsive behaviours found in OCD patients. This suggests that the high serotonin levels do have a causational link to compulsive behaviours

However, this research was done on animals, who have differences neurologically, cognitively, and socially and so there may be a question of how generalisable the research findings are to development of OCD in humans

There is evidence based on drug treatments for the impact of low serotonin levels

antidepressant drugs which increase serotonin activity- such as SSRIs have been found to be successful in reducing OCD symptoms, while drugs that have less of an effect on serotonin were not found to reduce OCD symptoms. Furthermore, those with diseases like parkinsons often develop OCD type behaviours, which may be due to the same biological basis.

The success of serotonin related drug treatments provides evidence for the idea that low serotonin levels are at least partially responsible for the development of OCD

what is the focus of neural explanations for OCD

the idea that there are abnormal brain circuits and areas of the brain may not be functioning appropriately

what neural areas are linked to OCD

abnormal functioning of the frontal lobes and left parahippocampal gyrus

linked to negative emotions and impaired decision making

particularly linked to hoarding disorder

what are the roles of the frontal lobes and the parahippocampal gyrus

frontal lobes are responsible for logical thinking and decision making

parahipocampaly gyrus linked to processing negative emotions

what is the normal circuit in the frontal lobe

the Orbitofrontal Cortex sends messages through the Caudate nucleus in the basal ganglia to the Thalamus about things that are worrying

the Caudate nucleus (in the basal ganglia) normally filters and suppresses signals if they are minor in nature from the Orbitofrontal cortex

what happens if the Caudate nucleus is damaged

it fails to suppress minor worry signals and the thalamus is repeatedly alerted

this sends signals back to the Orbitofrontal cortex

AO3 for neural explanations

There is research support for neural explanations

There is support for the idea of abnormal brain circuits

Research support for neural explanations

studies have shown there are anatomical differences in the brains of people with OCD and their families. Menzies (2007) showed there was reduced grey matter in the Orbitofrontal Cortex of OCD patients and their first degree relatives

This supports the view that OCD is inherited and the idea that it has a neural cause

there is support for the idea of abnormal brain circuits

PET scans of people with OCD taken while symptoms are active show heightened activity in the Orbitofrontal cortex where serotonin and dopamine are linked to. Serotonin plays a key role in the operation of the OFC and caudate nucleus so abnormal levels may cause misfunctioning in this area. Dopamine is also linked, being the main neurotransmitter of the basal ganglia.

The scientific evidence for the neurological basis of OCD supports this as a contributory factor, as well as supporting psychology as a science

AO3 for the biological approach to OCD overall

There are alternative explanations to the development of OCD

There are alternative explanations to the development of OCD

There is strong evidence from the behavioural approach that the two process model can be applied to OCD

Initiation caused by association between the NS (eg dirt) and UR of anxiety. The association is maintained by avoidance of the anxiety provoking stimulus. An obsession is then formed and a link is learned with compulsive behaviours such as hand washing which appear to reduce the anxiety.

This suggests that biological explanations may be incomplete or reductionist. This may create issues for treatment as drug treatments may not be suitable for all cases of OCD.

what are the biological treatments for OCD

drug treatments-

antidepressants

Anti anxiety drugs

What are the types of antidepressants

SSRIs

Tricyclics

how do SSRIs work

reduce anxiety related to OCD. They increase serotonin levels to regulate mood and anxiety.

They are released into a synapse from the presynaptic axon terminal and target receptor cells on the receiving neuron, then being absorbed into the presynaptic neurone

they decrease/inhibit reuptake of serotonin to increase levels and stimulation into the postsynaptic neuron

How do tricyclics work

work in the same way as SSRIs but also block reuptake of noradrenaline (which may also cause OCD), to leave more of these neurotransmitters in the synapse and have prolonged activity.

what anti anxiety drugs are commonly used

benzodiazepines (BZs)

how do anti anxiety drugs work

slow down CNS activity by enhancing activity of GABA as an inhibitory neurotransmitter

GABA locks into receptors and opens a channel increasing flow of chloride ions

this makes it harder for neuron to be stimulated by other neurotransmitters making the person feel more relaxed (including dopamine)

AO3 for drug treatments for OCD

Drug treatments have been found to be effective

Drugs are the preferred treatment

there can be side effects

Drug treatments are not a cure

There is publication bias in research

Drug treatments have been found to be effective

In comparisons between drug treatments and placebos as a control it has been found that drug treatments are effective. Soomro (2008) reviewed 17 studies on the use of SSRIs on OCD patients and found them more effective than placebos in reducing symptoms for up to 3 months after treatment

This means drug treatments can reduce OCD which can be a debilitating illness, and so this is a clear positive of this treatment

Drugs are the preffered treatment

They require little time and effort from the user, and less time and resources for health services. They are cheaper than other forms of psychotherapy and require little monitoring which is a positive for the NHS and mental health services as there is an ability to treat more patients more effectively and more quickly

There are side effects of drug treatments

SSRIs cause nausea, headaches and insomnia

Tricyclics cause hallucinations and irregular heartbeat- only used where SSRIs are not effective

BZs- increased aggressiveness, long term impairment of memory and addiction limits their use to max 4 weeks

these side effects can put restrictions on the use of specific drug treatments, and can cause patients to stop taking the drugs if side effects become too severe, which may limit their usefulness in treatment

drug treatments are not a cure

APA review of treatments for OCD suggested even though drugs are more commonly used and are relatively effective in the short term. psychotherapies eg CBT should be tried first

Drugs do not provide a long lasting cure and patients may relapse within a few weeks if treatment is stopped

This means drug treatments may not be the best option for treatment of OCD as it can lead to relapse as it doesnt actually cure OCD but just removes symptoms for a time

There is a publication bias in research into drug treatments

there is evidence of a publication bias towards studies that show a positive outcome of antidepressant treatment, exaggerating the benefits of such drugs. Positive results are more likely to be published and studies where findings were not positive were published in a way suggesting a positive outcome

Drug companies have a strong interest in the continuing success of psychotheraputic drugs and much of the research is funded by them

This means the suggested success of drug treatments may actually be a result of publication bias, rather than actual success, and other treatments may actually be more appropriate