OCD

Repetitive behaviour accompanied by obsessive thinking.

• OCD: characterised by either obsessions and/or compulsions. Most people have a diagnosis of OCD have both obessions and compulsions.
• Trichotillomania: compulsive hair pulling
• Hoarding disorder: the compulsive gathering of possessions and the inability to part with anything, regardless of its value.
• Excoriation disorder: compulsive skin picking

Compulsions -

• Repetitive - sufferers feel compelled to repeat a behaviour.
• Reduce anxiety - Around 10% of sufferers show compulsions alone - they have no obsessions, just a general sense of irrational anxiety. However, for the vast majority compulsive behaviours are performed in an attempt to manage the anxiety produced by obssessions.

Avoidance -

• Attempt to reduce anxiety by keeping away from situations that trigger it. However, this can interfere with living a normal life.

Anxiety and distress -

• Obsessive thoughts are unpleasant and frightening and the anxiety that goes with these can be overwhelming.

Acompanying depression -

• Anxiety can be accompanied by low mood and lack of enjoyment in activities.

Guilt and disgust -

• irrational guilt or disgust which may be directed at something external or the self.

Obsessive thoughts -

• Always unpleasant. Occur in around 90% of sufferers

Cognitive strategies to deal with obsessions -

• People respond by adopting cognitive coping strategies. This may help a person manage anxiety but can make them appear abnormal to to others and can distract them from everyday tasks.

Insight into excessive anxiety -

• Sufferers are aware that their obsessions and compulsions arent rational.
• OCD sufferers experience catastrophic thoughts about the worst case scenarios that might result if their anxieties were justified.

• Genes are involved in vulnerability. Lewis (1936) observed that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD.
• Diathesis-stress model: certain genes leave some people more likely to suffer a mental disorder but it isn't certain - some environmental stress is necessary to trigger the condition.

Candidate genes -

• Genes that create vulnerability for OCD. Some of these genes are involved in regulating the development of the serotonin system. For example, the gene 5HT1-D beta is implicated in the efficiency of transport of serotonin across the synapses.

OCD is polygenic -

• Not caused by a single gene, several are involved. Up to 230 may be involved, including htose associated with dopamine as well as serotonin.

Different types of OCD -

• aetiologically heterogenous - the origin has different causes.

There is good supporting evidence -

• Twin studies. Netadt et al (2010) reviewed previous twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non-identical twins.

Too many candidate genes -

• Several genes are involved and each genetic variation only increases the risk of OCD by a fraction.
• A genetic explanation provides little predictive value.

Environmental risk factors -

• Environmental factors can trigger or increase the risk of developing OCD.
• Cromer et al (2007) found that over half the OCD patients in their sample had a traumatic event in their past and that OCD was more severe in those that had more than once trauma.
• Cannot be entirely genetic in origin.

The role of serotonin -

• Neurotransmitters are responsible for relaying the information from one neuron to another. If a person has low levels of then normal transmission of mood-relevant information does not take place and mood - and sometimes other mental processes - are affected.
• Some cases of OCD may be explained by a reduction in the functioning of the serotonin system in the brain.

Decision making systems -

• Hoarding disorder may be associated with abnormal functioning of the lateral frontal lobes of the brain. (responsible for logical thinking and making decisions)
• Parahippocampal gyrus (processes unpleasant emotions)

Some supporting evidence -

• Some antidepressants work purely on the serotonin system and are effective in reducing OCD symptoms.
• OCD symptoms form a part of a number of other conditions that are biological in origin (e.g. Parkinson's disease)

Not clear which neural mechanisms are involved -

• Research has identified brain systems that may be involved sometimes but not always.

Shouldn't assume the neural mechanisms cause OCD -

• Evidence to suggest that various neurotransmitters and structures of the brain don't function normally in patients with OCD. However, abnormal functioning doesn't necessarily cause OCD.
• The biological abnormalities could be a result rather than a cause.

The serotonin-OCD link may be co-morbity with depression -

• The serotonin system is disrupted in many patients with OCD because they're depressed as well.

Twin-studies are flawed as genetic evidence -

• Overlooks the fact that identical twins may be more similar due to their envrionment as well. For example, if non-identical twins were a boy and girl then they would be brought up slightly differently.

SSRIs -

• Selective serotonin reuptake inhibitor (SSRI) is an antidepressant drug. It prevents the reabsorption and breakdown of serotonin which increases its levels in the synapse and continues to stimulate the post-synaptic neuron.
• Fluoxetine - 20mg a day typically. Takes 3-4 months of daily use to see benefits.

Combining SSRIs with other treatments -

• Drugs are often used alongside CBT. The drugs reduce emotional symptoms which allows patients to engage more effectively with CBT.

Alternatives to SSRIs -

• Tricyclics: older. E.g. Clomipramine. Same effect on the serotonin system, more severe side effects.
• SNRIs: (serotonin-noradrenaline reuptake inhibitors). Increase levels of serotonin and noradrenaline.

Effective at tackling OCD symptoms -

• Reduces symptoms and improves quality of life. Soomro et al. (2009) reviewed studies comparing SSRIs to placebos. Found that all 17 studies had significantly better results for SSRIs.
• Typically symptoms decline for around 70% of patients. With the remaining 30% using an alternative or therapy.

Cost-effective and non-disruptive -

• Cheap compared to psychological treatments. Good value for the NHS.
• Also non-disruptive to patient's lives.

Side-effects - reduce effectivness because people stop taking the medication

• Such as, indigestion, blurred vision and loss of sex drive. (temporary)
• Clomipramine - 1/10 patients suffer erection problems, tremors and weight gain. Over 1/100 become aggressive and have disruption in their blood pressure and heart rhythm.

Unreliable evidence for drug treatment -

• Some psychologists believe the evidence favouring drug treatments is biased because the research is sponsored by drug companies who don't report all the evidence.

Some cases of OCD follow trauma -

• OCD can have a range of other causes, other than biological.