Schizophrenia

What is Schizophrenia?

A type of psychosis, a severe mental disorder in which thoughts and emotions are so impaired that contact is lost with external reality

Schizophrenia…

• is the most common psychotic disorder

• affects about 1% if the population

• is most often diagnosed between the ages of 15 and 35 years

• is more commonly diagnosed in men than women, in cities than in the countryside and in working-class rather than middle-class people

To be diagnosed with Schizophrenia you must…

Have two (or more) of the following, each present for a significant portion of time during 1-month period (or less if successfully treated)

• delusions (false thoughts), hallucinations (false experiences), disorganised speech (e.g. frequent derailment or incoherence), grossly disorganised or catatonic behavior, negative symptoms (i.e. diminshed emotional expression or avolition)

Positive Symptoms

Reflect an excess or distortion of ‘normal’ functioning

Delusions (false beliefs)

• Bizarre beliefs that seem real to the person with schizophrenia, but they are not real

• Sometimes these delusions can be paranoid (i.e. persecutory) in nature

• Delusions may also involve inflated beliefs about the person’s power and importance

• There may also be delusions of reference where it is believed that events in the env

Hallucinations (false perceptions)

• Bizarre, unreal perceptions of the environment that are usually auditory (hearing voices) but may also be viual (seeing lights, objects or faces), olfactory (smelling things) or tacitle (e.g. feeling that buys are crawling on or under the skin)

• May schizophrenics report hearing a voice or voices telling them to do something (i.e. hurt themselves or others) or commenting on their behaviour

Negative Symptoms

Reflecting a reduction or loss of ‘normal’ function

Speech Poverty

• Lessening of speech fluency and productivity, reflecting slow or blocked thoughts

• May produce fewer words in a test of verbal fluency (e.g. names as many animals as you can in one minute) due to a difficulty in spontaneously producingg the words

• May also be reflected in less complex syntax e.g. fewer clauses, shorter utterances (associated with long illness and early onset of illness)

Avolition

• The reduction of, or inability to initiate and persist in, goal-directed behaviour (e.g. sitting in the house for hours every day, doing nothing)

• Avolition is distinct from poor social function or disinterest, but is often confused with this

Reliability

The consistency of a measuring tool (e.g. the DSM) or other tests used in diagnosis - a test/tool must be valid for it to be reliable

Test-retest Reliability

Doctors must be able to reach the same conclusions about a patient at two different points in time, the DSM and other tests must enables this to occur, so a patient isn’t ‘labelled’ with a diagnosis when then changes or is re-diagnosed as another condition later on

Inter-rater Reliability

The extent to which different assessors agree on their assessments - doctors must reach the same conclusions about a patient’s diagnosis, the DSM and other tools must enable inter-rater reliability e.g. doctors should be able to consult the DSM about a patient, independently from each other and achieve the same diagnosis

Evaluation of Reliability - Cultural Differences

Research suggests there is significant variation between countries when it comes to diagnosing schizophrenia i.e. culture has an influence on the diagnostic process - Copeland (1971) gave 134 US and 194 British psychiatrists a description of a patient, 69% of the US psychiatrists diagnosed schizophrenia but only 2% of the British ones did

Evaluation of Reliability - Research Support

• Rosenhan (1973) - the unreliability of diagnosis was highlighted by Rosenhan’s famous study in which ‘normal’ people presented themselves to psychiatric hospitals in the US, claiming that they heard an unfamiliar voice in their head

• They were all diagnosed as having schizophrenia and admitted - throughout their stay, none of the staff recognised that they were not actually displaying symptoms of schizophrenia

Validity

• The extent to which a diagnosis is accurate and meaningful - the correctness of a diagnosis - this means that it must represent something real and be distinct from other disorders

• The DSM must enable a valid diagnosis to be made, by ensuring it measures what it claims to measure (symptoms of a disorder, schizophrenia) which is different to other mental health conditions and enables psychiatrists to recognise symptoms and provide treatment

Evaluation of Validity - Gender Bias

• Occurs when accuracy of diagnosis is dependent on the gender of an individual

• This may occur due to gender-biased diagnostic critera, or clinicans basing their judgements on stereotypical beliefs held about gender

Evalution of Validity - Symptom Overlap

Many of the symptoms of schizophrenia are also found in other disorders such as depression and bipolar disorder

Evaluation of Validity - Co-morbidity

• Refers to the extent that two or more conditions co-occur

• Schizophrenia often occurs alongside substance abuse, anxiety and depression

• If conditions occur together a lot of the time, then this calls into question the validity of their diagnosis and classification (may actually be a single condition)

Heredity

Schizophrenia tends to run in families and the risk of an individual developing schizophrenia is higher for those with biological relatives with schizophrenia than those without it - it is thought that different combinations of genes make a person more vulnerable to schizophrenia

Genetic Explanations

• Candidate genes are ones which, through research, have been implicated in the development of schizophrenia

• Schizophrenia is thought to be polygenic - this means that its development is not determined by a single gene but a few, and there is little predictive power from this explanation

• Genes associated with the increased risk included those coding for the functionning of a number of neurotransmitters including dopamine

Family Studies

• Genes play an important factor, however if genes were the only cause of schizophrenia then the percentages surely would be 100%

• The theory could be seen as deterministic - just because we are ‘predisposed’ by our genes cannot mean we necessarily get the disorder schizophrenia

• Studies show that schizophrenia is more common in biological relatives then non-biological relatives, and that the closer the degree of genetic relatedness, the greater the risk

Twin Studies

• If Monozygotic (MZ) twins are more concordant than Dizygotic (DZ) twins, then this suggests that the greater similarity is due to genetics

• Joseph (2004) points out that MZ twins are treated much more similarly, encounter more similar environments and experience more ‘identity confusion’ (frequently being treated as ‘the twins’ rather than as individuals) than DZ twins

Adoption Studies

• A way of truly seperating the influence of genetics and environment, by investigating individuals who are genetically related by reared apart

• Tienari et al (2000) found that of 164 adoptees whose biological mothers had been diagnosed with schizophrenia, 6.7% also received a diagnosis, compared to just 2% of the 197 control adoptees (born to non-schizophrenic mothers)

Dopamine Hypothesis

Claims that an excess of the neurotransmitter dopamine in certain regions of the brain is associated with positive symptoms of schizophrenia - messages from neurons that transmit dopamine fire too easily or too often, leading to hallucinations and delusions

Hyperdopaminergia in the Subcortex

The original version of the dopamine hypothesis focused on the high levels of dopamine in the subcortex i.e. central areas of the brain - an excess of dopamine receptors in Broca’s area (speech production) may be associated with speech poverty and auditory hallucinations

Hypodopaminergia in the Subcortex

More recent versions of the dopamine hypothesis have focussed dopamine in the cortex - Goldman-Rakic found that low levels of dopamine in the prefrontal cortex was linked to negative symptoms of schizophrenia

Drugs that increase dopaminergic activity

Amphetamine is a dopamine agonist (it stimulates nerve cells containing dopamine, causing the synapse to be flooded with dopamine)

Drugs that decrease dopaminergic activity

There are many different antipsychotic drugs but what they all have in common is that they block the activity of dopamine, thus eliminating symptoms such as hallucinations and delusions

Neural Correlates

• Changes in neuronal events and mechanisms that result in the characteristic symptoms of a behaviour or mental disorder

• Neural correlates are measurements of the structure or function of the brain that occur in conjunction with an experience, in this case schizophrenia

Ventricular Space

• People with schizophrenia have abnormally large ventricles in the brain

• Ventricles are fluid filled cavities

• This means that the brains of schizophrenics are lighter than normal

Ventral Striatum

• Activity in the ventral striatum has been linked to the development of avolition (loss of motivation)

• The ventral striatum are believed to be particularly involved in the anticipiation of a reward for certain actions

• Therefore, if there is abnormality in areas such as the ventral striatum, the this would result in a lack of motivation (avolition)

Superior Temporal Gyrus

• Reduced activity in the superior temporal gyrus and anterior cingulate gyrus have been linked to the development of auditory hallucinations

• Patients experiencing auditory hallucinations showed lower activiation levels in these areas than controls

• Therefore, reduced activity in these areas of the brain is a neural correlate of auditory hallucinations

Amygdala

• Responsible for basic feelings such as fear, lust and hunger

• Smaller in schizophrenics so can link to loss of emotion (affective flattening)

Prefrontal Cortex

• Helps people think logically and organise their thoughts

• Many schizophrenics have lower activity in this area which could be linked to delusions and disorganised thoughts

Evaluation of Neural Correlates - Empirical Evidence

Findings are inconsistent and therefore inconclusive - MRIs have made it possible to investigate living brain images which is an advance on merely having to rely on post mortems

Evaluation of Neural Correlates - Correlational Evidence

There are, however, issues of causality - cause and effect cannot be established with brain abnormalities/reduced functioning predispose to schizophrenia, or whether the onset of clinical symptoms causes these changes

Typical Antipsychotics

• Typical drugs work by reducing the effects of dopamine and therefore reducing the symptoms of schizophrenia (hallucinations and delusions)

• They are dopamine antagonists (they bind to, but do not stimulate, dopamine receptors; especially the D2 receptors)

• Block dopamine receptors in the synapses and can also have a sedation effect

Atypical Antipsychotics

• Compared to typical antipsychotics, atypical antipsychotics have a lower risk of side effects, have a beneficial effect on negative symptoms and cognitive impairment, and are suitable lfor treatment-resistant patients

• Target dopamine and serotonin

• Reduces depression and anxiety as well as improving cognitive functioning

• Work by blocking D2 receptors, but unlike typical antipsychotics, they rapidly dissociate to allow normal dopamine transmission; this is what leads to less side effects

Evaluation of Drug Therapy - Evidence

• Evidence shows that antipsychotics are moderately effective - typical better than placebo, atypical better than typical

• Side effects: typical - dizziness, weight gain, grimacing, NMS (blocking a dopamine action in the hypothalamus)

• This means that antipsychotics can do harm as well as good and individuals who experience these may avoid such treatments (which makes the treatment ineffective

Issue/Debate of Drug Therapy - Nature vs Nurture

In an interactionist approach, treatments will take more than one form - antipsychotic medication will often be used alongside CBT, acknowledging the role that biological and psychological factors play in the disorder

Family Dysfunction

Explanations based on family dysfunction claim that schiziphrenia is caused by abnormal patterns of communication within the family and living within a dysfunctional family

The Schizophrenogenic Mother

• Based on a type of parent that is cold, rejecting and controlling and tends to create a family climate characterised by tension and secrecy

• Leads to distrust that later develops into paranoid delusions and ultimately schizophrenia

Double Bind Theory

• Suggests that children who frequently receive contradictory messages from their parents are more likely to develop schizophrenia: for example, if a mother tells her son that she loves him but at the same time turns her head away in disgust

• These messages invalidate each other so the child is unable to respond, which in turn prevents the development of an internally coherent construction of reality - in the long run manifests itself into schizophrenic symptoms

Expressed Emotion

• The level of emotion expressed towards the patient; includes verbal criticism, hostility and emptional overinvolvement/anger

• The family members of the schizophrenic patient talk about the patient in a critical or hostile manner, or in a way that indictates over-involvement with the patient or their behaviour

• High levels are most likely to influence relapse rates, and people with schizophrenia have a lower tolerance for these intense interactions

Evaluation of Family Dysfunction - Inconclusive Support

• Poor evidence base for any of the explanations

• Although there is plenty of evidence suppprting the idea that childhood family-bases stress is associated with adult schizophrenia, there is almost none to support the importance of traditional familt-based theories such as the schizophrenogenic mother and double bind

Issue/Debate of Family Dysfunction - Social Sensitivity

• Although early explanations for the family-schizophrenia link have no research support, research in this area may be useful in showing that insecure attachment and experience of childhood trauma affect individual vulnerability to schizophrenia

• Research linking family dysfunction to schizophrenia is highly socially sensitive because it can lead to parent-blaming

Dysfunctional Thought Processing

• Schizophrenia is characterised by disruption to normal thought processing

• Reduced thought processing in the ventral striatum is associated with negative symptoms, whilst reduced processing of information in the temporal gyrus is associated with hallucinations (positive symptoms)

Metarepresentation

• The ability to reflect on thoughts and behaviours

• This allows us insight into our own intentions and goals - it also allows to interpret the actions of others

• Dysfunction disrupts our ability to recognise our own actions and thoughts as being carried out by ourselves rather than someone else

Lack of Central Control

• Issues have also been identified with the cognitive ability to suppress automatic responses while we perform deliberate actions

• Speech poverty and thought disorder could result from the inability to suppress automatic thoughts

• For example, people with schizophrenia tend to experience derailment of thoughts because each word triggers associations, and the person could not suppress autonomic responses to these

Cognitive Explanations of Delusions

• When delusions are formed the patient’s interpretations of their experiences are controlled by inadequate information processing

• A critical characteristic of delusional thinking is egocentiric bias - this leads to the individual jumping to false conclusions about external events

Evaluation of Cognitive Explanations - Research Support

• Stirling et al (2006) compared performance on a range of cognitive tasks in 30 people with schizophrenia and a control group of 30 people without schizophrenia

• Task included the Stroop task, in which participants have to name the font - colours of colours - words, so have to suppress the tendency to read the words aloud

• People with schizophrenia took longer - over twice as long

Issue/Debate of Cognitive Explanations - Reductionist

• Can only provide proximal explanation

• Cognitive explanations for schizophrenia are proximal explanations because they explain what is happening now to produce symptoms - as distinct from distal explanations which focus on what intially caused the conditions

• Ignores genetic and family dysfunction explanations

CBT

Used to help the patient identify and correct faulty interpretations of events and to help establish links between their thoughts, feelings or actions and their symptoms in order to consider alternative ways of explaining why they think and behave the way they do

Evaluation of CBT - Appropriateness

• Limited availability - around 1 in 10 who could benefit get access to this form of therapy

• Length of therapy can be a practical issue (drop out rates) - a significant number refuse or fail to attend, therefore limiting effectiveness

Issue/Debate of CBT - Idiographic vs Nomothetic

• Takes a more idiographic approach to treatment, as the therapist considers the individual patient’s view which is often seen as a strength as the individual is taken into consideration

• This is in stark contrast to biological treatments which take a nomothetic approach by viewing the cause of schizophrenia as biological, therefore assuming that the same treatment(s) should work for all patients