Download 2 bio explanation and treatment for OCD

BIOLOGICAL
EXPLANATION FOR
OCD
Psychopathology:
The biological approach
to explaining OCD:
genetic and neural
explanations
LEARNING OUTCOMES
By the end of the session you will be able to:
Describe the biological explanation for OCD, including genetic
and neural explanations
Consider evidence that supports the explanation
Evaluate the two explanations considering alternative ideas
Describe the biological treatment for OCD
Explore evidence for drug therapy and develop an evaluation
for the treatment
BASIC ASSUMPTIONS OF
BIOLOGICAL APPROACH
Everything psychological is at first biological
The approach investigates how biological structures and
processes within the body impacts on behaviour.
Remember these?
Much of human behaviour has a physiological cause which may be
genetically or environmentally altered.
Genes affect behaviour and influence individual psychological
differences between people. Evolutionary psychology considers genetic
influences in common behaviours
Psychologists should study the brain, nervous system and other
biological systems, e.g. hormones, chemicals acting on the brain
GENETICS…
a genetic component to OCD
predisposes some individuals
If a person develops OCD, partly due to their genes - may explain
why patients often have other family members with OCD
Nestadt et al (2000) first degree relatives (parents, siblings, children)
11.7% chance of developing disorder
2.7% first degree relatives in control group (no OCD)
Twin studies are used to explore this explanation….
CORRELATIONS AND TWIN RESEARCH
Correlations show relationships between 2 sets of data. (i.e. how
closely they match)
A correlation coefficient is a number between
+1 and -1 expressed as a decimal .
Eg
+0.86
The direction of the number ie positive or negative indicates whether
the relationship is positive (as one goes up the other goes up) or
negative (as one goes up the other goes down)
The nearer to plus or minus one the number is shows how
strong the relationship is.
When looking at twin or adoption studies we tend to look for positive
relationships as it would be very strange if the closer the biological
relationship the more unlike someone we were
COMPARING….
When we say we compare twins, or comparing children with
parents we mean on a measurable variable and because we
are psychologists this will be something to do with behaviour
for example
Intelligence
Aggression
Introversion/extroversion
Sense of humour
Mental illnesses such as depression or schizophrenia
Psychologists talk about
concordance rates
CONCORDANCE RATES
Simply the correlation coefficient converted from a decimal to
a percentage.
A correlation coefficient of 0.79
becomes
A concordance rate of 79%
TWIN STUDIES
With twin studies there are 2 main methods
1. comparing concordance
rates of monozygotic twins
with dizygotic twins
2. Comparing monozygotic
twins reared together with
monozygotic twins reared
apart
ADOPTION STUDIES
With adoption studies we tend to compare the
adopted child with the biological mother and the
adoptive mother to see which correlation
coefficient is highest
E.g.
Child and adoptive mother 0.42
Child and biological mother 0.72
RESEARCH
Bellodi et al (2001) used evidence from twin studies and family studies showed that close relatives are more likely to have the disorder than
more distant relatives.
Mckeon and Murray- patients with OCD are morl likely to have first
degree relatives who suffer from anxiety disorders.
Pauls et al- there is a much higher percentage of OCD sufferers in
relatives of patients with OCD than in the control group without OCD.
Miguel et al (2005) looked at identical twins… if one twin has OCD, the
other has 53% - 87% chance of having OCD too.
Non identical twins – 22% - 47% chance
Argued that upbringing between pair of identical twins and pair of non
identical twins is minimal so environment cannot be used as an
explanation
Environment is implicated to a point…
Non identical twins are no more similar than siblings but research is
suggesting that they are more likely to get OCD if one of the pair has it
So what is the difference between non identical twins and siblings???
Born at the same time
Environments are much more similar
Share similar traits?
GENETIC
EXPLANATIONS CONT.
Research has suggested that Candidate genes are implicated
in the development of OCD.
A possible candidate gene is the SERT gene which is involved in
regulating serotonin, a neurotransmitter which facilitates message
transfer across synapses.
Another possible candidate gene is the
production of dopamine
Dopamine effects motivation and drive
COMT gene – this regulates the
COMBINATION?
But…. Does everyone in a given family gets OCD??
No… so there must be additional factors
E.g. The diathesis–stress model suggests that people gain a
vulnerability towards OCD through genes
but
an environmental stressor is needed… such as a stressful event, e.g. a
bereavement
OCD is thought to be polygenic –its development is not determined by a
single gene but a few (maybe as many as 230 genes, Taylor, 2013) – suggesting
that there is little predictive power from this explanation
EVALUATION OF GENETIC
EXPLANATIONS
Genetics
S – Lots of evidence to suggest there is a genetic component
to the disorder. One of the best sources of evidence for the
importance of genes is twin studies (Nestadt – 2010)
C - Family studies could also be used to explain
environmental influences
C - Close relatives of OCD sufferers may have observed and
imitated the behaviour (SLT)
L - It is difficult to untangle the effects of environment and
genetic factors
EVALUATION OF GENETIC
EXPLANATIONS
Candidate genes
S - Candidate genes are ones which, through research, have
been implicated in the development of OCD.
L - There are too many genes involved
L - Psychologists have not been successful at pinning down all
the genes involved
C - Each genetic variation only increases the risk of OCD by a
fraction suggesting there may be other explanations
EVALUATION OF GENETIC
EXPLANATIONS
Combination of genes and environment:
Individuals may gain a vulnerability towards OCD through
genes that is then triggered by an environmental stressor.
S- Cromer (2007) found that over half the OCD patients in
their sample had a traumatic event in the past, and that
OCD was more severe in those with more than one
trauma
 This means that it may more productive to focus on environmental
causes as it seems that not all OCD is entirely genetic in origin
NEURAL EXPLANATIONS
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
Abnormal levels of
certain
neurotransmitters
Certain brain
circuits may be
abnormal
RECAP OF NEUROTRANSMITTERS -
SEROTONIN
Serotonin appears to be the main
neurotransmitter associated with OCD
Serotonin = implicated in sleep, memory, emotions, appetite
and social and sexual behaviour
Plays a part in preventing repetition of tasks
A lack of serotonin would therefore prevent the ability to inhibit the
repetition of tasks…. So repetition would occur
NEURAL EXPLANATIONS
Neuroimaging (brain scans) techniques allow
comparisons to be made between normal and
abnormal brain patterns
Basal ganglia - implicated in OCD
This area of the brain is responsible for innate
psychomotor functions
Wise and Rapoport (1989) proposed the hypersensitivity of the
basal ganglia gives a rise to the repetitive motor behaviours
seen in OCD, for example, repetitive
washing/cleaning/checking
NEURAL EXPLANATIONS
Other brain areas believed to be involved in OCD include the
orbitofrontal cortex (OFC) and the thalamus
The thalamus is a brain area whose functions include cleaning,
checking and other safety behaviours.
NEURAL EXPLANATIONS
OFC is involved in decision
making and worry about social and other
The
behaviour.
In OCD the OFC and the thalamus are
believed to be overactive.
An overactive thalamus would result in an
increased motivation to clean or check
for safety.
If the thalamus was overactive the OFC
would also become overactive as a result.
An overactive OFC would result in
increased anxiety and increased
planning to avoid anxiety.
The orbital
frontal cortex
EVALUATION OF NEURAL
EXPLANATIONS
The role of neurotransmitters
A - Allows medication to be developed which helps
sufferers.
L - Drugs are not completely effective
C - Just because administering SSRIs decreases OCD
symptoms does not mean that this was the cause in the
first place
L - There is time delay between taking drugs to target
the condition and any improvements being made and yet
the chemical imbalance is addressed in hours
EVALUATION OF NEURAL
EXPLANATIONS
Areas of the brain
A / S - Advances in technology have allowed researchers to investigate
specific areas of the brain more accurately, and OCD sufferers do seem to
have excessive activity in the orbital frontal cortex
E - Cleaning and checking behaviours are "hard-wired" in the thalamus
L - The repetitive acts (compulsions) may be explained by the structural
abnormality of the basal ganglia but not necessarily the obsessional
thoughts.
C - There are inconsistencies found in the research as no system has been
found that always plays a role in OCD
C - These neural changes could be as a result of suffering from the
disorder, not necessarily the cause of it
TASK – 5 MINS
Pg 34 in your packs… OCD can be explained by the two
process model. In your notes, apply this model to OCD
This can be part of your evaluation … Conflicting Evidence
ESSAY
Describe and evaluate the
biological approach to explaining
OCD
(12 marks)
BIOLOGICAL
TREATMENT FOR
OCD
Psychopathology:
The biological approach
to explaining treating
OCD: drug therapy
DRUG THERAPY
Common used biological therapy
for anxiety disorders is drug
therapy
Assumes that there is a chemical
imbalance in the brain
Can be corrected by drugs either increase or decrease the
levels of neurotransmitters in the
brain
SSRI (SELECTIVE SEROTONIN
REUPTAKE INHIBITORS)
Standard medical treatment used to tackle the symptoms of
OCD are SSRIs
SSRIs work on increasing certain neurotransmitter in the
brain by preventing the re-absorption of serotonin.
By preventing the re-absorption of serotonin, SSRIs
effectively increase its levels in the synapse and thus
continue to stimulate the post-synaptic neuron
Serotonin in the post synaptic neuron – regulation of
preventing repetition of tasks
COMBINING SSRIS WITH
OTHER TREATMENT
Drugs are often used alongside cognitive-behavioural therapy (CBT)
Drugs reduce the sufferer’s emotional symptoms, such as anxiety or
depression
Therefore the patient can then engage more effectively with CBT
Some sufferers may respond best to CBT alone without the need for
medication
ALTERNATIVES
Sometimes an SSRI is not effective….after three to four months the
dose can be increased or it can be combined with other drugs
Patients respond differently to different drugs and sometimes
alternatives work well for some people and not at all for other, e.g.
tricyclics, SNRIs
EVALUATION OF DRUG THERAPY
FOR OCD
Using your text books, complete the evaluation table on pg 37 in your
packs using these headings to help:
Drugs can have side-effects …
Drugs may not treat the causes…
OBB
As with all drugs, relapse rates are apparent…
Drug therapy is effective at tackling OCD symptoms…
Drugs are cost-effective and non-disruptive..
Unreliable evidence for drug treatments…
GHG
Some cases of OCD follow trauma …
Also, add Foe et al to your Psychopathology research bank.
 What is a Randomized control trial? Ensure you can describe this type of experiment
Drug therapy is effective at tackling OCD symptoms
There is clear research to suggest that SSRIs are effective in
reducing the severity of OCD symptoms (Soomro: 2009)
Drugs are cost-effective and non-disruptive
Drug treatments are cheap in comparison to psychological
treatments and, unlike psychotherapy, they are nondisruptive to patients’ lives
Drugs can have side-effects
Although the use of drugs is effective for most, a significant
minority receive no benefit and/or may suffer side-effects:
weight gain, dry mouth, sexual dysfunction and loss of
memory. Coming off a drug is a slow process in which the
dosage has to be gradually reduced over a period of six
months – risk of relapse.
Unreliable evidence for drug treatments
If drug companies sponsor the research they may decide to
supress any results that do not support the drug they are
marketing. Currently many drug companies do not publish all of
their results and may indeed be supressing evidence.
This suggests that the data on the effectiveness of drugs may
not be trustworthy.
Some cases of OCD follow trauma
Although OCD is widely believed to be biological in origin, it is
also accepted that OCD can have different causes. There is a
case for proposing that cases of OCD where there is no family
history of OCD, but there is a relevant life event, should be
treated differently from those where there is a family history
and no trauma. It may be that for these cases drugs are not
appropriate.
CAN YOU…?
1. Explain the role of genes in OCD. (4 marks)
2. Explain two limitations of genetic explanations for
OCD. (4 marks)
3. Outline the neural basis of OCD (4 marks)
4. Briefly describe one argument in favour of a neural
basis to OCD. (2 marks)
5. Evaluate the biological approach to explaining OCD. (8
marks)
ESSAY
Describe and evaluate the
biological approach to the
treatment of OCD
(12 marks)