- Created by: lauratoogood
- Created on: 29-04-19 09:07
Behavioural Characteristics of OCD
Repetitive compulsions: sufferers feel compelled to repeat behaviour, e.g. washing hands.
Compulsions reduce anxiety: compulsive behaviours are performed in an attempt to manage the anxiety produced by obsessions.
Avoidance: sufferers will avoid situations to reduce anxiety in events which may trigger it, e.g. a person with a fear of birds staying inside, this can interfere with everyday normal life.
Emotional Characteristics of OCD
Anxiety and distress: the urge to repeat behaviour causes anxiety.
Accompanying depression: OCD can be accompanied by depression (lack of motivation), compulsive behaviour tends to bring temporary relief.
Guilt and disgust: OCD tends to bring irrational guilt, over minor moral issues or disgust which may be directed at something external like dirt.
Cognitive Characteristics of OCD
Obsessive thoughts: for over 90% of sufferers, their major cognitive feature is obsessive thoughts.
Cognitive strategies to deal with obsessions: a sufferer may be tormented by irrational guilt, the sufferer may react by doing a compulsive act in order to feel relieved. They may seem abnormal to others and this may distract them from everyday tasks.
Insight into excessive anxiety: sufferers are aware that thief obsessions and complsions are not rational. OCD sufferers experience catastrophic thoughts about worst case scenarios that might result if their anxieties were justified. Hyperventilation occurs, i.e. they maintain cnostant alertness.
Genetic Explanations of OCD
Genes are involved in individual vunerability to OCD. Lewis (1936) observed that his OCD patients, 37% had parents with OCD and 21% had siblings with OCD, suggesting OCD runs in family. According to the diathesis stress model, certain genes leave some people more vinerable than others.
Candidate genes: researchers have identified genes which create vunerability for OCD, called candidate genes. Some of these genes are involved in regulating the development of the serotonin system. E.g. gene 5HT1-D beta is implicated in the efficiency of transport of serotonin across synapses.
OCD is polygenic: this means that a single gene, rather multiple genes, does not cause OCD. Taylor (2013) analysed studies from the past and found evidence that up to 230 different genes may be involved with OCD. Genes that have been studied include those associated with dopamine as well as serotonin, both neurotransmitters believed to have a role in regulating mood.
Different types of OCD: one group of genes may have caused OCD in one person, but a different group in another. this is called aetiologically heterogeneous, meaning the origin of OCD has different causes. There is also evidence that suggests that different types of OCD may be the result of particular genetic variations, such as hoarding and religious obsession.
Evaluation of the Genetic Explanations for OCD
Supporting evidence: a variety of sources support the idea of vunerability to OCD as a result of genetic makeup. One of the best sources include twin studies, Nestadt (2010) reviewed previous twin studies and found that 68% if identical twins shared OCD as opposed to 31% of non-identical twins. This strongly supports genetic influence on OCD.
Too many candidate genes: Although twin studies suggest that OCD is under genetic control, psychologists haven't been successful in pinning down which genes are involved. This is because it appears several genes are involved and that each variation only increases OCD by a fraction. It's unlikely to ever be useful as it provides little predictive value.
Environmental risk factors: can trigger or increase the risk of developing OCD (the diathesis stress model). E.g. Cromer et al (2007) found that over half of OCD patients in their sample had a traumatic experience in their past and that OCD was even more severe in those with more than one trauma. This suggests OCD cannot be entirely genetic in origin, at least not all cases.
Neural Explanations of OCD
The genes associated with OCD are likely to affect the levels of key neurotransmitters as well as structures of the brain. These are neural explanations.
Role of serotonin:
Serotonin regulates mood. Neurotransmitters are responsible for relaying information from one neuron to another. Low levels of serotonin means transmission of mood relevant information do not take place. Sometimes other mental processes are affected. Some cases of OCD may be explained by a reduction in functioning of the serotonin system.
Decision making systems:
Some cases of OCD in particular hoarding seems to be associated with impaired decision making. This may be associated with the abnormal functioning of the lateral frontal lobes of the brain. The frontal loves are the front part of your brain (behind the forehead) that is responsible for logical thinking and decision-making. There is also evidence that the parahippocampalgyrus is associated with processing unpleasant emotions, functioning abnormally in OCD.
Evaluation of the Neural Explanations of OCD
Supporting evidence: there is evidence to support neural mechanisms in OCD. E.g. some antidepressants work purely on the serotonin system, increasing the levels of the neurotransmitter, such drugs are effective in reducing OCD symptoms and this suggests that the serotonin system is involved in OCD.
Not clear which neural mechanisms are involved: studies of decision making have shown that these neural systems are the same systems that function abnormally in OCD (Cavedini et all 2002). However, research has also identified other brain systems that may be involved sometimes but no system had been found that always plays a role in OCD. We cannon therefore claim to understand neural mechanisms involed in OCD.
We shouldn't assume neural mechanisms cause OCD: there is evidence that suggests that various neurotransmitters and structures of the brain to not function normally in patients with OCD. However this is not the same as saying that this abnormal functioning causes OCD. These biological abnormalities coud be a result of OCD rather than it's causes.
Drug Therapy for OCD
Drug therapies for mental disorders aim to increase or decrease levels of neurotransmitters in the brain to increase/decrease their activity.
SSRI's: work on the serotonin system in the brain. Serotonin is released by the presynaptic neurons and travels across a synapse. By preventing the re-absorption and the breakdown of the serotonin, SSRI's effectively increase its levels in the synapse and thus continue to stimulate the postsynaptic neuron.
Combining SSRI's with other treatments: drugs can also be used alongside CBT to treat OCD. In practice some people respond best to CBT alone whilst other benefit more from drugs like Fluoxetine. Occasionally other drugs are prescribed alongside SSRI's.
Alternatives to SSRI's: when SSRI's are not effective the dosage can be increased or it can be combined with other drugs, sometimes different antidepressants. Patients respond differently to different drugs.
Tricyclics: (older antidepressants) have more severe side effects, and are reserved for patients who do not respond to SSRI's
SNRI's: increase the levels of serotonin and other neurotransmitters like noradrenaline.
Evaluation of Drug Therapy for OCD
Drug therapy is effective: There is supporting evidence of SSRI's working on patients and thus improving their lives. Soomro et al (2009) reviewed studies comparting SSRI's to placebos. He concluded that all 17 studies showed the significant improvements of OCD when patients used SSRI's than placebos. The effectiveness was greater when SSRI's were combined with CBT.
Cost effective and non-disruptive: Drugs are cheaper than psychological treatment, therefore using drugs to treat OCD is good for the public health systems like the NHS. Compared to psychological therapies, SSRI's are non-disruptive to patients lives.The patient can simply decide to take the drugs till the symptoms decline.
Drugs can have side effects: Although SSRI's are helpful, some patients do not benefit from them and they have side effects, such as indigestion, blurred vision and loss of sex drive. These side effects are usually temporary. For those taking Clomipramine, side effects are more common and can be serious. More than one in ten patients suffer erection problems, tremor and weight gain. More than one in a hundred become aggressive and suffer disruption to blood pressure.