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Psychopathology:

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Psychopathology: Biological explanations of OCD Evaluation of genetic factors (AO2) + Concordance rates for twin studies generally high compared with other disorders ... – PowerPoint PPT presentation

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Title: Psychopathology:


1
  • Psychopathology
  • Biological explanations of OCD

2
What are the characteristics of someone with
Obsessive-compulsive disorder (OCD)?
  • Obsessions recurrent, intrusive thoughts or
    impulses that are perceived as inappropriate,
    grotesque or forbidden (DSM-IVR).
  • The obsessions generally cause anxiety as they
    are unlike the sufferers typical thoughts. These
    thoughts are believed to be uncontrollable, the
    sufferer feels as though they may lose control
    and act upon these obsessions. The most common
    obsessions take the form of
  • DOUBTS IMPULSES IMAGES.
  • Compulsions Repetitive acts that work to reduce
    anxiety of the sufferer by preventing some
    dreaded event happening (DSM-IVR).
  • These behaviours can be hidden i.e. mental acts
    or overt i.e. hand washing.
  • The vast majority of sufferers realise their
    behaviour is irrational but feel compelled to
    perform the given behaviour for fear of
    something terrible occurring, thus the behaviour
    also create anxiety.
  • OCD is an anxiety disorder. The behaviours are
    ritualistic, (hand washing, constant checking)
    and is therefore is the source of great anxiety.
  • Interestingly the disorder is equally common in
    both men and women and the onset of the behaviour
    is usually in young adult life.
  • Again you could think of the disorder as having
    two components
  • Obsessions.
  • Compulsions.

3
What are the characteristics of someone with
Obsessive-compulsive disorder (OCD)?
  • A diagnosis is given if the sufferer fits the
    following criteria
  • Recurrent persistent thoughts, impulses or images
    that feel intrusive and inappropriate, and cause
    excessive anxiety or distress.
  • The sufferer partakes in regular repetitive
    behaviour
  • (hand washing). The behaviour must not be related
    in anyway to what they are designed to prevent.
  • The individual recognises the behaviour is
    excessive and product of their own mind.

4
Biological explanations of OCD.
  • Genetic Factors (A01)
  • Family/Twin Studies- Nestadt et al (2000) 80
    patients with OCD 343 of their near relatives
    compared with 73 control patients without mental
    illness 300 of their relatives. Strong link
    with near family (5x greater risk if had first
    degree relative).
  • Meta-analysis of 14 twin studies found on average
    MZ twins 2x more likely to develop the disorder
    if their co-twin had it than DZ twins.
  • COMT gene COMT helps to reduce the action of
    dopamine. The variation in the COMT gene
    decreases the amount of COMT available and
    therefore dopamine is not controlled and there is
    probably too much. Researchers collected DNA
    samples from 73 people with OCD and 148 who did
    not have a mental disorder. The variation in the
    gene occurred in nearly half of the men with OCD
    but only 10 of women with OCD. It was found in
    about 17 of those with good mental health.
  • .

5
Evaluation of genetic factors (AO2)
  • Concordance rates for twin studies generally
    high compared with other disorders (e.g.. 87)
  • The OCD symptoms of parents and their children
    are often different which suggests the disorder
    is not learned.
  • -However, concordance rates are never 100 which
    means that OCD is not entirely genetic.
  • COMT gene- study by Schindler confirmed
    association but didnt find gender differences
    found previously.
  • -Research rarely replicated as this is a new area
  • /-Other genes being discovered all the time
    unlikely to be just one gene.
  • - Studies before 1990 difficult to interpret due
    to differences in diagnostic criteria.
  • -Problems with twin studies they may not be
    truly identical. Problems with bias in diagnosis.
  • -Difficulties in separating effects of
    environment and genetics.

6
Biochemical Factors(AO1)
  • Serotonin Lower levels of serotonin found in
    OCD sufferers .
  • Dopamine levels are thought to be abnormally high
    in people with OCD- thus suggesting other
    neurotransmitters are involved in OCD.

7
Evaluation of biochemical factors
  • Studies using drugs have shown a reduction in
    dopamine levels is positively correlated with a
    reduction in OCD symptoms.
  • Experiments which inject animals with drugs that
    increased levels of dopamine have caused the
    animals to demonstrate OCD type behaviours.
  • Drugs that increase serotonin (anti depressants
    have been shown to reduce OCD symptoms.
  • - But research results relating to serotonin are
    varied sometimes symptoms have been made worse.
    There is a great deal of contradictory research.
  • - Drugs seem to show only partial alleviation of
    the symptoms so the process is not fully
    understood. The exact function of
    neurotransmitters in the development of OCD is
    far from understood.
  • -Cause or effect- it may be that neurotransmitter
    levels fluctuate as a result of OCD rather than
    as a cause of it.

8
Neuroanatomy
  • Brain Dysfunction
  • Basal Ganglia abnormalities in prefrontal cortex
    where thinking and judgement takes place is often
    present in OCD sufferers.
  • OCD is often found in cases of Tourettes and
    Parkinsons disease which are all disorders in
    which the basal ganglia is implicated.
  • Basal ganglia damage resulting from head injuries
    can also cause OCD.
  • Surgery which disconnects the basal ganglia from
    the frontal cortex can reduce symptoms of severe
    OCD

9
Neuroanatomy
  • Brain Dysfunction
  • Another area implicated is the OFC circuit. The
    OFC sends worry signals. These signals are
    normally suppressed by the caudate nucleus. In
    OCD the caudate nucleus is thought to be damaged
    so it cannot suppress the signals which become
    increasingly excited increasing compulsive
    behaviour and anxiety.

10
Evaluation of neuroanatomy explanation
  • Basal ganglia and OFC
  • Neuro imaging studies have shown increased
    activity in basal ganglia in OCD sufferers.
  • - However results of neuro imaging studies have
    been inconclusive and basal ganglia impairment
    has not been found in all OCD patients.
  • Scans show increased activity in OFC in OCD
    patients.
  • It has been demonstrated that OFC damage caused
    by head injury, viruses and tumours can give rise
    to OCD.
  • Menzies (2007) supported both neuroanatomical
    and genetic explanations make notes on the
    study (207)

11
Evaluation of biological explanations
  • Promising research but cannot yet offer a
    complete explanation.
  • One of most powerful challenges to this view is
    that PSYCHOLOGICAL interventions show a strong
    therapeutic effect and yet do not rely on drugs
    or make any physical intervention.

12
Examination questions on biological explanations
  • January 2010
  • Outline one biological and one psychological
    explanation for obsessive compulsive disorder (9)
  • Evaluate explanations for obsessive compulsive
    disorder (16)
  • June 2010
  • Not examined -Psychological therapies and
    clinical characteristics
  • January 2011

13
Psychological explanations of OCD
  • Psychodynamic
  • Freud OCD arises when unacceptable wishes and
    impulses from the ID are only partially repressed
    and so provoke anxiety. The use of ego defence
    mechanisms reduce the anxiety. The 3 most common
    defences in terms of OCD are
  • isolation ( people attempt to isolate
    themselves, or disown undesirable thoughts and
    impulses. When the forces of the ID dominate, the
    impulses intrude as obsessional thoughts.
  • undoing ( when isolation fails the second
    defence of undoing produces compulsive
    acts-washing away unacceptable impulses)
  • reaction formation (taking on traits that are
    opposite to the unacceptable impulses-such as
    compulsive kindness may be a way of countering
    unacceptable aggressive impulses.)

14
Psychodynamic-Adler
  • Inferiority complex explanation-
  • Some parents dominate their children and prevent
    them from developing a sense of their own
    competence. When this happens an inferiority
    complex may result so that later, as adults,
    these people may adopt compulsive rituals such as
    tidying out drawers, in order to carve out an
    area in which they exert control of something and
    can feel competent.

15
Psychological explanations of OCD
  • Freud used the evidence of Rat Man to support
    his explanations
  • Some researchers have suggested that the therapy
    developed by Freud (Psychoanalysis) may have a
    negative effect on OCD recovery.
  • -Difficult to test the idea of unconscious
    motivations. No convincing evidence to support
    the PD view of OCD and psychoanalysis has been of
    little help in helping people to overcome OCD.

16
Psychological explanations of OCD.
  • Behavioural
  • Mowrer suggested that the learning of fears is a
    two step process
  • Classical conditioning A neutral stimulus becomes
    associated with anxiety through Classical
    Conditioning.
  • Operant conditioning Any action that enables the
    individual to avoid a negative event is negative
    reinforcement. Avoidance of the fear leads to
    positive outcomes and is therefore reinforced.
  • Thus the compulsive behaviour becomes a way of
    establishing control and reducing anxiety- and
    as a result the behaviour is reinforced and the
    behaviour may become compulsive whenever the
    individuals face thoughts that provoke anxiety.

17
Psychological explanations of OCD.
  • Behavioural evaluation AO2
  • Researchers thought that if Mowrer was right,
    that OCD patients are predisposed to more rapid
    conditioning. Research did support this finding,
    OCD patients were conditioned more rapidly.
  • Further research (Rachman) has shown that
    compulsions do relieve the anxiety of obsessional
    thoughts. In a series of experiments OCD
    patients were asked to carry out some
    prohibited activity such as touching something
    dirty. Patients were then allowed to carry out
    their compulsion (showed reduction in anxiety).
    If however they were asked to delay carrying out
    their compulsive activity their anxiety levels
    were found to persist for a while then gradually
    decline. Compulsions therefore provide a quicker
    relief from anxiety.
  • This theory has led to development of a
    reasonably effective therapy ERP.
  • - Theory does not explain the CAUSE of the
    obsessive thoughts, it explains how they are
    maintained. (e.g. aspirins might cure headaches
    but headaches are not due to lack of aspirin in
    the body!)

18
Cognitive explanations of OCD
  • Cognitive
  • Everyone has unwanted or intrusive thoughts from
    time to time but these thoughts can be ignored or
    dismissed fairly easily.
  • For some people irrational thoughts cannot be
    ignored and feel overwhelming leading to the
    expectation that terrible things will happen.
  • The thoughts continue because the person cannot
    ignore them.
  • This is also because they often have depression.
  • In order to avoid the consequences of these
    thoughts the sufferer must neutralise them.
    This only provides temporary relief and then the
    anxiety builds up again.
  • Over time people become more convinced that
    these thoughts are dangerous and they become
    obsessions.
  • The need to reduce the anxiety they cause becomes
    a compulsion.

19
Evaluation of cognitive explanations of OCD
  • Research has supported the idea that people
    with OCD have different patterns of thinking,
    such as believing that they should have total
    control over their world.
  • Research has also shown that people with OCD
    have more intrusive thoughts than normal
    people.
  • The Rachman research also supports the cognitive
    explanation as well as the behavioural
    explanation.
  • CBT therapies have been shown to be reasonably
    effective in treating OCD.
  • -the theory is more descriptive than explanatory
    why do people develop OCD in the first place?
    We all have intrusive thoughts but dont all get
    OCD.

20
Conclusion
  • No single explanation can account for a complex
    disorder like OCD
  • Likely to be an interaction between biological,
    psychological and social factors.
  • Diathesis stress model- certain individuals have
    an underlying biological predisposition to OCD.
    This may develop fully in response to
    environmental triggers.
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