P1 - Psychopathology - biological approach to OCD Flashcards
describe the two types of twins and how are they used in psychology?
Monozygotic (MZ) twins share 100% of their genes and are known as identical twins.
Dizygotic (DZ)twins share 50% of their genes and are known as unidentical twins.
Researchers can use these to study mental disorders by comparing concordance rates in mz twins with those in dz twins.
A high rate in mz twins compared to dz twins indicates a strong genetic cause, whilst more similar MZ and DZ concordance rates would suggest an environmental cause.
The dz twins act as an excellent environmental comparison, If a disorder is entirely genetic we would expect a 100% concordance for MZ twins.
study into OCD and biology?
Miguel et al (2005) – if one identical twin has OCD, there is a 53-87% chance that the other twin will also develop it
Non identical twins – show 22-47% chance
This shows that genes are involved in development of OCD because 53%-87% of twins develop it. However there is still a 47%-13% chance of not developing it so this is down to phenotype and environmental factors. In addition the fact that the concordance rates are to do with identical twins could not be do to with the fact they are twins and is instead to do with the fact that they are treated similarly.
study into genetic vulnerability of OCD
Genes are involved in vulnerability for OCD. Lewis (1936) observed that of his OCD patients, 37% had parents with OCD and 21% had siblings with OCD, suggesting it runs in families. Pauls et al. (1995) found that the risk of OCD was significantly greater in first-degree relatives of OCD subjects as compared to relatives of psychiatrically normal controls (10% vs 1.9%)
what is the diathesis stress model?
According to the diathesis stress model, certain genes leave people more likely to suffer from a mental health disorder but it is not certain – some environmental stress is necessary to trigger the condition
evaluation studies of OCD and biology?
However, there does not appear to be one single gene. Pato et al (2001) suggests that although OCD is heritable, few details about the genetic mechanisms are well understood, therefore we need more focused research.
One group of genes may cause OCD in one person, but a different group of genes cause it in another meaning it is aetiologically heterogeneous
Nature/nurture - Although research does suggest a genetic component, there must be some environmental influences, or else the concordance rates between MZ twins would be 100%.
What is the confounding variable with twin studies?
The way in which the twins are treated tends to be very similar however not 100% of the twins have the same results. Twin’s life experiences tend to be very similar and they generally have very similar access to things such as education. So therefore this obscures the results as it is not only genes as the independent variable.
study to support diathesis stress model of OCD?
Cromer (2007) found over half the OCD patients in their sample had experience a traumatic event in their past.
Explain in relation to the diathesis stress model
The diathesis model suggests that although some genes make people more susceptible to experiencing OCD; the traumatic event acts as a trigger. However this was only half of the patients.
neural explanations to OCD
Serotonin – Pet scans show low levels of serotonin in the brain link to OCD, in particular, obsessive thoughts. Also drugs that increase serotonin reduce OCD symptoms.
Orbital Frontal Cortex – high levels of activity in this area of the brain is associated with higher level though processing, and turning sensory thoughts into actions. It may be that those with OCD have difficulty ‘switching off’ these areas and ignoring impulses, which in turn end up as obsessions.
Some forms of OCD has also been linked to breakdown in the immune system functioning, for example through contracting streptococcal throat infections, Lyme’s disease and influenza, indicating a biological explanation through damage to neural mechanisms
evaluation of the neural explanations to OCD
Zohar et al (1987) – a drug that reduces serotonin (mCPP) was given to OCD patients – this enhanced their symptoms. This showed that there is a relationship between low levels of serotonin and OCD.
In addition Hu (2006) found that serotonin levels were lower in OCD patients than non-sufferers, which supports that idea that serotonin is not the full cause.
BUT not all sufferers respond positively to serotonin enhancing drugs, relapse rate is high – According to Simpson et al. (2004), up to 45% of patients treated with Clomipramine relapsed within 12 weeks of completing medication.
which lessens the support for this neurotransmitter being the sole cause of the disorder.
describe treating OCD through drug therapy?
Drug Therapy
Antidepressants – SSRIs elevate levels of serotonin by causing the blocking of re-uptaking of serotonin and continuation of binding to the receptor therefore causing levels to function at more normal levels.
E.g fluoxetine (Prozac) is used most commonly used SSRI in adults, Clomipramine is the most commonly used SRI for OCD (known as a tricyclic antidepressant)
Anxiolytic drugs – used to lower anxiety
Antipsychotic drugs – lower dopamine levels are given if SSRIs prove ineffective.
SSRI - selective serotonin re-uptake inhibitor
evaluation of treating OCD through drug treatment
Relapse rate is high – According to Simpson et al. (2004), up to 45% of patients treated with Clomipramine relapsed within 12 weeks of completing medication.
This shows that patients were more very likely to relapse because 45% relapsed therefore the treatment must not be very effective. This is likely because the treatment is treating the symptoms rather than the cause, however 55% still do not relapse.
SRIs have unpleasant side effects, Clomipramine has risks with tiredness, weight gain and heart seizures. Due to this, combined with the effectiveness of psychological treatments, some people argue that drug treatments should not be used
Because of the side effects people might stop taking the drug and therefore the treatment would not work.
However, Pigott and Seay (2007) found that SSRIs were consistently effective in reducing OCD symptoms and have less side effects than Clomipramine BUT they don’t cure OCD as they do not tackle the underlying cause.
evaluate the costs of dug treatment?
Although drug treatment is cheaper in the short run. Over the course of several years due to not being permanent; CBT may be more cost effective.
Although SSRIs are fairly effective and any side effects will probably be short-term, like all drug treatments there is some controversy. It may be biased because the research is sponsored by drug companies who do not report all the evidence (Goldacre, 2013).
explain an alternate treatment to OCD?
Psychosurgery
Involves destroying tissue in the brain to disrupt the cortico-striatal circuit by the use of radio-frequency waves. This has an effect on the orbital frontal cortex and is associated with a reduction in symptoms. There has been a recent movement towards deep-brain stimulation, which involves use of magnetic impulses on the supplementary motor area of the brain, which is associated with blocking out irrelevant thoughts and obsessions.
evaluation of psychosurgery?
Richter et al (2004) 30% pf OCD patients had a 35% reduction in symptoms but there were occasional complications, such as seizures. As they were patients who were suicidal and had not responded to drug treatment, it was seen as effective.
Why is it a controversial treatment?
As some of side effects such as seizures and suicide are very concerning
The results are not worth the rates of bad side effects
Why might individuals with sever OCD be able to give consent to psychosurgery? Why is this a problem?
People who are very desperate to get rid of their illness are not in a suitable frame of mind to make these decisions.
implications of research into OCD
Psychological research findings into psychopathology may lead to improvements in psychological health/treatment programmes which may mean that people manage their health better and take less time off work. This would reduce costs to the economy
