Schizophrenia

• classification - short definition

  withdrawal from society
• classification - historical approach

  not used anymore

  • type 1 - acute, can be a single episode, characterised by positive symptoms, good recovery prospects
  • type 2 - chronic, persistant episodes, characterised by negative symptoms, poor recovery prospects

  DSM V doesn't have different types of schizophrenia because it's hard to categorise
• classification - positive symptoms

  losing a sense of reality/classic symptoms

  • hallucinations
  • delusions
  • disorganised speech
  • disorganised behaviour

  acute episodes and respond to treatment
• classification - negative symptoms

  disruptions of normal emotions and actions

  • apathy (lack of interest/concern)
  • alogia (speech poverty)
  • avolition (reduction of interests/desire)
  • affective flattening (reduce range of emotions)
  • anhedonia (loss of pleasure in activities)

  generally occur in chronic episodes and resistant to treatment
• classification - hallucinations

  distortion or exaggeration of perception in any of our senses - mostly visual or auditory
• classification - delusions

  firmly held beliefs caused by distortions of reasoning or misinterpretations of experiences
• classification - first rank symptoms

  Schneider (1959)

  • detailed first rank symptoms of SZ from subjective experiences based on patient's verbal reports

  1. passivity experiences/thought disorders - thoughts and actions percieved as under external control
  2. auditory hallucinations - voices in head
  3. primary delusions - delusions of grandeur, delusions of persecution
• Reliability + validity of diagnosis

  types of reliability

  reliability = consistency

  • test-retest - clinician makes the same diagnosis on different occasions from the same information
  • inter-rater reliability - different clinicians make same diagonses of same patients
• Reliability + validity of diagnosis

  reliability of research

  Beck et al (1962) - test retest: found 54% rate between practitioners diagnosing 153 patients using the DSM V

  Soderberg et al (2005) - 81% similarity rate using the DSM V
• Reliability + validity of diagnosis

  improvement in the DSM V

  Read et al (2004) - test-retest reliability is only 38%

  Seto (2004) - in Japan they diagnosed intergration disorder as SZ was not being diagnosed reliably

  Jacobsen et al (2005) - ICD-10 (worldwide, different criteria) classification system found concordance rate of 98%
• Reliability + validity of diagnosis

  validity types

  validity = accuracy

  • predictive validity - diagnoses lead to successful treatments then it's valid
  • descriptive validity - patients should differ in symptoms from patients with other disorders
  • aesthiological validity - same cause on being sane in insane places
• Reliability + validity of diagnosis

  Rasenhan

  Rasenhan (1975)

  • 8 people without mental illnesses admitted to psychiatric institutions
  • they were diagnosed with schizophrenia, bipolar etc
  • stayed up to 52 days
  • weren't treated properly and not diagnosed thoroughly, once they were in it was hard to get out
  • after the study he went to the institution and told them that some may get admitted on purpose
  • institution found 41 patients who may of not needed to be there, 1908 diagnoses were done by 2 people
• Factors affecting reliability and validity

  co-morbidity


  many who have schizophrenia also have another mental illness

  • defenition - the extent that 2 or more conditions/diseases occur simultaneously
• Factors affecting reliability and validity

  co-morbidity research

  it can affect reliability and validity:

  • Sim et al (2006) - 32% of 142 SZ also have an additional disorder
  • Goldman et al (1999) - found 50% of SZ had another disorder
  • Buckeley et al (2009) - 50% have depression, 15% panic disorders, 29% PTSD and 25% OCD
• Factors affecting reliability and validity

  co-morbidity - evaluation

  - Jeste et al (1996) - SZ with co-morbid disorders are often excluded from research - issues with generalising of causes and treatments

  - high levels of co-morbid disorders have led to some arguing they're actually seperate sub types

  - hard to reliably diagnose SZ from bipolar -> similar mood changes

  - alcohol + weed + cocaine are often abused by SZ patients -> hard to get reliable and valid diagnoses, hallucinations and delusions may not come from SZ
• Factors affecting reliability and validity

  symptom overlap

  symptoms of a disorder overlap with another disorder, makes it difficult for clinicians to decide which disorders someone is suffering from

  • lots of different disorders overlap with schizophrenia
• Factors affecting reliability and validity

  symptom overlap - research

  Serper et al (1999) - patients with co-morbidity SZ and cocaine abuse, found that accurate diagnoses can still be made

  Konstantareas et al (2001) - compared 14 autistic patients with 14 SZ patients, 7 of the autistic patients had SZ symptoms but the SZ didn't have autism symptoms

  * Ophoff et al (2011) - genetic material from 50,000 patients and found 7 gene locations associated with SZ, 3 locations are also associated with bipolar -> genetic overlap
• Factors affecting reliability and validity

  culture bias

  tendency to over-diagnose members of other cultures as suffering from SZ

  • Britain - Afro-Caribbean people are more likely to be diagnosed and confined to mental hospitals
• Factors affecting reliability and validity

  culture bias - causes

  possible reasons:

  • racism
  • cultural differences
  • ethnic differences in symptom expression are overlooked or misinterpreted by British practitioners
  • suggested that racism could be involved in the culture bias found in the diagnosis and treatment of SZ
• Factors affecting reliability and validity

  culture bias - facts and figures

  Cochrane (1977) - incidence of SZ in West Indies and Britain is similar to around 1% but those of Afro-Caribbean origin are 7x more likely to be diagnosed when living in Britain

  McGovern and Cope (1977) - 2/3 of patients detained in Birmingham hospitals were 1st and 2nd generation Afro-Caribbean and the 1/3 were white and Asians

  Ineichen (1984) - 34/89 people in containments in closed wards in Bristol hospitals were non-white
• Factors affecting reliability and validity

  culture bias - Escobar (2012)


  white psychiatrists may over-interpret symptoms of black people during diagnosis

  • such factors as cultural differences in language and mannerisms, difficulties in relating between black patients and white therapist
• Factors affecting reliability and validity

  gender bias

  tendency for the diagnostic criteria to be applied differently to males and females

  • differences in classification of the disorder - historically, type 1 and 2

  3 main differences:

  • age difference
  • symptom differences
  • hormone differences
• Factors affecting reliability and validity

  gender bias - age differences

  all research, historically, was androcentric and we expect development of SZ in females to be the same as men - people probably misdiagnosed because females don't follow the male trend

  • 1st onset of SZ in males is earlier = 18 - 25 years
  • 1st onset of SZ in females = 25 - 35 years
  • 2 peaks in males = 25 and 39
  • 3 peaks in females = 22, 37 and 62
• Factors affecting reliability and validity

  gender bias - symptom differences

  males tend to have more severe SC and negative symptoms

  males are more likely to higher levels of substance abuse

  males are more resistant to treatment

  • androcentric research leads to misdiagnoses
• Factors affecting reliability and validity

  gender bias - hormonal differences

  Kulkarni et al (2001) - female sex hormone (estradial) was effective in treatment combined with antipsychotics -> suggesting different protection and pre-disposing
• Factors affecting reliability and validity

  gender bias - research

  Lewin et al (1984) - clear diagnostic criteria applied, female sufferers fall

  Castle et al (1993) - a more restrictive diagnostic criteria had 2x more male sufferers of SZ than female

  Haro et al (2001) - relapse rates are higher in males, recovery rates are higher in females
• biological explanations - genetics

  genetic link

  SZ transmitted through herederitary means

  • no single SZ gene
  • these genes are said to increase an individual's vulnerability to SZ
  • to figure out whether genes have a play we study MZ twins and compare them to DZ twins
  • we'd expect MZ twins to have a high concordance rate, meta-analysis showed 48% concordance rate in MZ twins
• biological explanations - genetics

  investigating genetic bias

  research into twins, families and adopted children to assess concordance rates between people with different levels of relatedness and genetic similarity

  - gene-mapping studies - used to compare SZ patients and 'normal' people
• biological explanations - genetics

  research

  Gottesman and Shields (1976) - reviewed 5 twin studies, concordance rate between 75% and 91% for MZ twins with severe form of SZ

  Schizphrenia Working Group of Psychiatric Genomics Consortium (2014) - 150,000 patient's DNA, found 128 gene variations at 108 locations on chromosomes
• biological explanations - genetics

  evaluation

  + gene-mapping offers possibility to develop tests on identifying high-risks - ethical issues - finding different diseases like dementia, is the patient told?

  - confusing evidence - concordance rates of 11% to 75%

  - if genes were the only factor, concordance should be 100%

  - twin studies - genetic factor, ignores the environment
• biological explanations - dopamine

  dopamine hypothesis


  claims that increased dopamine is associated with positive symptoms

  • messages from neurons that stransmitted too easily/often
  • leads to hallucinations and delusions (positive)
  • SZ - leads to increased D2 receptors on the post-synaptic neuron
• biological explanations - dopamine

  amphetamines


  increases dopamine activity

  • speed up messages travelling between brain and body
  • dopamine agonist (stimulates and floods nerve cells)
  • Parkinson's -> higher dopamine in patients
• biological explanations - dopamine

  antipsychotics


  decreases dopamine

  • helps symptoms from returning
  • neural pathways, decreased dopamine eliminates positive symptoms
  • lower effects of SZ = better arguement that dopamine plays a role in SZ
• biological explanations - dopamine

  revised dopamine hypothesis

  Davis and Kahn (1991) - positive symptoms caused by increased dopamine in specific brain areas (mesolimbic pathways)

  • negative symptoms caused by decreased dopamine in other areas (Prefrontal Cortex)
• biological explanations - dopamine

  revised dopamine hypothesis - evidence


  animal studies:

  • Wang and Deutch (2008) - reduced dopamine in the PFC in rats and it led to cognitive impairments, this was reversed using drugs that work on human negative symptoms

  neural imaging:

  • Patel et al (2010) - PET scans - assess dopamine levels in SZ and non-SZ, found lower levels of dopamine in the PFC in SZ patients
• biological explanations - dopamine

  evaluation

  + evidence is scientific

  + treatment

  + PET scans - comparing SZ and non-SZ

  - biologically determinstic - ignored environment and free will -> SZ is only due to biology

  - temporal validity

  - animal studies

  - dopamine - cause or result of SZ

  - Noll (2009) - 1/3 of SZ don't respond to the drug treatment, which blocks dopamine
• biological explanations - neural correlates

  brain abnormalities in specific areas in brain maybe associated with the development of SZ

  • past - limited to post-morterm studies
  • now - fMRIs - non-invasive, can compare SZ and non-SZ
  • linked, maybe not a cause
• biological explanations - neural correlates

  research

  Johnstone et al (1976) - post morterms, SZ had enlarged ventricles

  Li et al (2010) - lower activation in the amyglada, can't regulate emotions (anhedonia)

  Boos et al (2012) - SZ had lower grey matter density, don't have as many neural correlates

  Yoon et al (2013) - SZ had lower activity in PFC when completing a memory task compared to non-SZ
• biological explanations - neural correlates

  frontal lobe

  lower grey matter volume leads to impairments of executive functions
• biological explanations - neural correlates

  limbic system

  limbic reactivity is increased during processing in neutral material, especially amyglada reactivity