Schizophrenia

What is schizophrenia

Severe mental disorder where contact with reality and insight are impaired

What is classification

Organising symptoms into categories based on which symptoms cluster together in people with mental disorders

What are the two major systems for classification

ICD-10 : International Classification of Disease, 10th Edition

DSM-5 : Diagnostic and Statistical Manual, 5th Edition

DSM Classification

Looks for one or more positive symptom

ICD classification

Looks for two or more negative symptoms

What are positive symptoms

Things that are in addition to normal experience

What are the positive symptoms of schizophrenia

Hallucinations

Delusions

Hallucinations

Unusual sensory experiences, may or may not have a relation to the environment

Can be tactile, auditory and visual

Delusions

Irrational beliefs that can take any form

Grandiose = Person believes they are famous, omnipotent, very high status

Persecution = Person believes they are being hunted, e.g. by government

What are negative symptoms

Abnormal experiences where there is a loss of normal experience

Negative symptoms of schizophrenia

Avolition

Speech poverty

Avolition

Find it difficult to begin or maintain a task

Andreason : Three identifying signs = Poor hygiene, lack of persistence of work or education, lack of energy

Speech poverty

Reduction in the amount or quality of speech

DSM 5 = Speech disorganisation

Considered a positive symptom by DSM 5

Speech is incoherent, lacks train of thought

EVAL : Reliability of classification , Cheniaux et al

2 psychiatrists diagnose 100 people using DSM and ICD, inter-rater reliability was poor

1 : DSM= 26 ICD=44

2: DSM=13 ICD=24

DSM under diagnoses and ICD over diagnoses

EVAL: Validity, including Cheniaux

Validity = extent to which we are measuring what we claim to be measuring

Criterion validity = Cheniaux highlights how DSM under-diagnoses and ICD over-diagnoses, therefore criteria vary too much to be valid

What is co-morbidity

Where / how often two conditions occur together

EVAL : Co-morbidity

Where there is high co-morbidity, it can question validity of diagnosis and the classification, as it could just be one disorder

EVAL: Co-morbidity, Buckley et al

50% of people diagnosed with SZ also have depression (50%), substance abuse (47%), PTSD (29%), OCD (23%)

Means we are bad at telling the difference between the disorders

Weakness of both diagnosis and classification

EVAL : Symptom overlap

SZ and bipolar both involve delusions and avolition

Questions both diagnosis and classification

EVAL: Gender bias

Longnecker et al : Since 80s, men have been diagnosed more often than women

Cotton et al: Women are able to mask their poor functioning better as there is expectations for role in life

EVAL: Gender bias, level of functioning

Cotton et al : Women appear to function better than men, being more able to maintain work life and good family relationships

May influence the lesser diagnosis

Brings into question the validity of diagnosis

EVAL: Cultural bias

African America or people of Afro-Caribbean origin are several times more likely to be diagnosed with SZ, without any increase in the countries themselves

Indicates a cultural bias

Symptoms may be more general acceptable due to cultural beliefs, but cultural traditions may be misconstrued by a person outside the culture

Familial genetic explanation: Gottesman

Gottesman : MZ twins = 48% chance, DZ = 17% chance, Parents = 6%

Hard to distinguish between environment and genetics

Strong relationship between degree of genetic similarity and risk of schizophrenia

Candidate genes

Schizophrenia is polygenic = requires a number of factors working in combination

Schizophrenia is aetiologically heterogenous: different combinations of factors could lead to SZ

Dopamine hypothesis

Hyperdopaminergia = higher levels of dopamine activity

Hypodopaminergia = lower levels of dopamine activity

Hyperdopaminergia in the subcortex

Higher dopamine in the central areas of the brain

Excess dopamine receptors in Broca’s area associated with speech poverty and/or auditory hallucinations

Hypodopaminergia in the cortex

Goldman Rakic et al : Low levels of dopamine in prefrontal cortex, related to negative symptoms of SZ

Prefrontal cortex used in decision making

What is a neural correlate

Structure /function of brain correlates with experience

Negative symptom neural correlates

Avolition = Lowered motivation, ventral striatum related to anticipation of reward, abnormalities may lead to avolition

Juckel et al : Decreased activity in ventral striatum in SZ ptp

Positive symptoms for neural correlates

Superior temporal gyrus and anterior cingulate gyrus

Allen et al : Scanned brain of ptp having auditory hallucinations, lower activation levels in areas of the hallucination group, more likely to mix up own and others voice

BIO EVAL : Correlation vs. causation

Is decreased activity in ventral striatum caused by SZ

Or does the SZ cause the decreased activity

BIO EVAL: Evidence for dopamine hypothesis

Tauscher et al: Antipsychotic drugs reduce dopamine activity

Lindstroem et a: Chemicals that produce dopamine are taken up faster in people with SZ, suggests they produce more dopamine

BIO EVAL: Evidence against dopamine hypothesis

Curran et al: Dopamine agonists (increase dopamine) make symptoms worse, and can induce symptoms in non-schizophrenics

Moghaddam and Javitt: Current research focussed on neurotransmitter called glutamate

BIO EVAL: Absence of family history

Brown et al: Positive correlation between paternal age and risk of schizophrenia

Increase of father age = increase risk of sperm mutation

BIO EVAL: Evidence for genetic susceptibility

Tienari et al: Adopted children with biological risk are more likely to develop SZ than those without biological component

Schizophrenogic mother

Fromm-Reichmann: Mother is cold, rejecting and controlling, family climate = tense and secretive

Distrust leads to paranoid delusions

Double Bind Theory

Emphasis on communication within family, receiving mixed messages about doing tasks and lack clarity

Getting task wrong = withdrawal of love (conditional love), left confused

Reflected in disorganised thinking and paranoid delusions

Expressed Emotion

From carer to person with schizophrenia, source of extreme stress triggers relapse

Elements: Verbal criticism, hostility toward person, emotional over-involvement with self-sacrifice

Cognitive : Dysfunctional thought processing

Metarepresentation and central control

Metarepresentation

Metarepresentation: Ability to reflect on own thoughts, gives insights into thoughts and goals

Faulty Metarepresentation = Inability to recognise actions and thoughts as own, provides explanation for delusions, think own thoughts may come from others

Central control

Suppresses automatic response and thoughts when performing deliberate actions

Disorganised speech and thought could come from inability to suppress thoughts e.g. derailment

EVAL : Support for family dysfunction

Read et al : 46 studies, 69% of woman patients had history of physical and/or sexual abuse

Berry et al : Adults with insecure attachments are more likely to have schizophrenia

EVAL : Family dysfunction, weakness

Schizophrenic patients have distorted perception of memory and family, interferes with validity

Blaming family can increase tension within the home, may make it more stressful

EVAL : Family based explanations

No evidence to support schizophrenogenic mother or double bind theory

History of parent blaming adds insult to injury and may become additional burden

EVAL : Dysfunctional information processing

Stirling et al : 30 SZ patients with 18 controls in Stroop Test, aligned with idea of central control dysfunction

SZ participants took twice as long

EVAL : Cognitive explanations and direction of causality

Links are clear but cognitive explanations do not tell us anything about origins

cannot tell which way biology and cognition influence each other

Typical antipsychotics e.g. chlorpormazine

Antagonists : reduce action of neurotransmitter, block dopamine receptors in synapses

Aim is to normalise levels of neurotransmission in key areas, reduces symptoms

Chlorpromazine : Gradual increase in dosage, sedative effect

Why were antipsychotics developed

Improve effectiveness of other drugs and decrease side effects

Atypical antipsychotic: Clozapine

Withdrawn due to agranulocytosis, blood condition

Found to be more effective then typical antipsychotics, put back on market but users need to do regular blood test

Dopamine antagonist, but also acts on serotonin and glutamate, improves mood and depression symptoms

Atypical antipsychotics : Risperidone

Developed to be just as effective as clozapine but without side effects

Binds to dopamine and serotonin, more strongly than clozapine

EVAL : Effectiveness of typical psychotics (chlorpromazine)

Thornley et al : Review of studies, comparing placebo vs chlorpromazine, 13 trials and 1121 participants

Chlorpromazine associated with better functioning, reduced symptom severity and better relapse rate

EVAL : Effectiveness of atypical antipsychotics

Meltzer : Clozapine more effective than typical antipsychotics, effective in 30-50% cases where typical antipsychotics have failed

Tests comparing types of atypical drugs are inconclusive, leading idea that it depends on person

EVAL : Side effects

Dizziness, agitation, sleepiness, weight gain, tardive dyskinesia (from dopamine super sensitivity)

Neuroleptic malignant syndrome: Blocking of dopamine in hypothalamus, leads to coma and potential death

Meltzer: Atypical antipsychotics generally succeed in having less side-effects

EVAL : Understanding of dopamine hypothesis

More developed understanding of dopamine hypothesis shows some areas LACK dopamine, and dopamine antagonists wouldn’t effective

EVAL : Problems with evidence

Healy : Suggests antipsychotics are calming drug which makes it easy to highlight the positive effect they have on schizophrenic people

CBT

Identify irrational thoughts and change/ challenge them, or alter the level of threat the individual sees them to be

Allows person to make sense of how their symptoms have an effect on their thoughts and feelings, can reduce anxiety and provide understanding

Family therapy

Aims to improve communication and interaction with family, reduce stress that may contribute to a risk of relapse

Pharoah : Form alliances, reduce stress for caring relative, improve problem solving, reduce anger and guilt, balancing caring and own life

Token economies

Management for developed patterns of harmful behaviour, aim is to improve quality of life

Token given as reinforcement for desirable behaviour, rewards are primary reinforcers

EVAL: CBT effectiveness

Jauhar et al: Reviewed 34 studies on CBT, found small but significant positive impact on negative symptoms

EVAL: Family therapy effectiveness

Pharaoh et al: Moderate evidence that family therapy reduces readmissions, improves quality of life

Inconsistent and lack quality

EVAL: Evidence for token economies

McMonagle and Sultana: 3 studies with random allocation of conditions, 110 participants

1/3 studies showed improvement of symptoms, 0/3 yielded useful info about behaviour change

EVAL: Treatment not cure

Reduce stress and manages/ challenges symptoms, modifies behaviour and makes life easier to live

EVAL : Ethical issues

Token economies : Removal/ inclusion of privileges is unfair to those with more severe symptoms, manipulation for the ease of care takers

EVAL : Quality of evidence for effectiveness

Small scale studies have more positive findings but lack wider perspective/ control

Conclusions from reviews are generally more optimistic

Meehl’s Diathesis Stress

Vulnerability is entirely genetic, no amount of stress can cause SZ without gene

In carriers of genes, chronic stress and schizophrenogenic mother can aid development

Modern understanding of diathesis

Ripke et al : 108 associated genes, no one schizogene

Understanding that diathesis is not just genetic, trauma can be diathesis and further stress can cause development of SZ

Read et al: Early trauma alters brain, hypothalamic-pituitary-adrenal system becomes over-active, makes person more vulnerable to stress in life

Modern understanding of diathesis : Trauma

Read et al : Early trauma alters brain

Hypothalamic Pituitary Adrenal system (feedback loop for stress) is overly sensitive so increases stress felt

Modern understanding of stress

Modern definition is anything that risks triggering SZ

More genetic vulnerability = less stress needed

Tienari et al. (Adoption study)

Children adopted from 19,000 mothers

Child rearing with high criticism and low empathy = increase risk of SZ for children with bio vulnerability

High risk children w/ adoptive families with low stress much less likely to develop SZ

Conclusion of Tiernari et al

Only those with bio vulnerability had increase chance of SZ

Combination of stress and genetic components

Modern understanding of stress : Cannabis

Increases chance by 7X

Interferes with dopamine system

Unlikely that just smoking will increase chance of SZ, needs 1 or more factor

Modern understanding of stress : Urban living

Vassos et al : Living in urban areas increase chance of SZ by 2.4X

Treatment according to interactionist model

Turkington et al : Possible to believe in bio causes and still use CBT for psychological symptoms

Not possible to just treat people with solely medicine

Interactionist treatment : Britain VS USA

Britain : Standard practice is antipsychotics and CBT

USA : Slower adoption of interactionist approach

EVAL : Original diathesis-stress model over-simple

Houston et al : Childhood sexual trauma can be vulnerability factor and cannabis use can be trigger

Older model of biological diathesis and stress as vulnerability is over simple

EVAL : Effectiveness in combo of treatment

Practical advantage as produces superior treatment outcomes

EVAL : Effective treatment, Tarrier et al

315 people with SZ randomly allocated MED + SUPPORT COUNSELLING group, MED + CBT group, MED only

People in combination groups show decrease symptoms than just MED group