Type 1: more positive symptoms (responds better to treatment)

Type 2: more negative symptoms (responds less to treatment)

Positive symptoms:

  • Hallucinations- preceptual disturbances
  • Delusions (grandure, paranoia)- cognitive symptoms 

Negative symptoms:

  • Avolitions (lack of personal care)
  • Speech poverty (echolalia)
  • psychomotor disturbances (no contro of muscles)
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Reliability of Diagosis

Test-retest reliability: on seperate visits diagnosis is the same 

Inter-rater reliability: diagnosis i sthe same for 2 different clinicians 

Causes of Unreliability in diagnosis:

  • Client/ Patient factors: may not be able to talk about mental state, relative on behalf may want diagnosis to over-emphasise, atypical symptoms may make it difficult
  • Clinician factors: how well they were trained, what approach they follow etc
  • Classification factors: differences between DSM-V and ICD. Billing in DSM may lead to bias in dignosis 

+ clients get correct treatment 

+ using a classification system, diagnosis is more refined 

- getting the worng psychiatric label can be deeply damaging 

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Validity of Diagnosis

Predictive validity: correctly predicting the prognosis 

Descripitive validity: symptoms are differentiated from other illnesses

Aestiolpgical validity: all people w an illness experiencing it the same way 

*Rosenhan: put people in a hospital claimign to hear voices, but act normally. Released between 1-52 dyas as SZ in remission 

- unethical as staff were desieved

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Culture Bias

*Sugarman: Afro-Carabean siblings/ next generation sibligs where between 8 and 15 times more lkely to be diagnsoed w SZ than white siblings.

+ in many culturees its normal to claim to hear voices or even disirable 

- doesnt explain why black people are more liekly to be diagnosed. Sugessted it has to do w immigrants catching flu in pregnancy which can increse SZ chance by a quarter.

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Gender Bias

*Castle: such drastic differences between men and women could sugest 2 different disorders, women experince effective psychosis not SZ.

  • Female: less severe, late onset, depressive, good prognosis 
  • Male: severe, early onset, negative symptoms, chronic 

Research evidence:

Incidence: Castle- males made up twice as much of the SZ population

Age of onset: clear differences in age of onset

Hormones: female onset in late 50s (linked to menopause) 

- differnces have been ignores (beta bias) 

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Genetic Explanation

General pop. risk: 1%

Relatuve w SZ risk: 6-17%

*Gottesman and Shields: twin study

  • MZ: 58%
  • DZ: 12%

Varma and Sharma: 34% in first degree relatives 

SZ working group: identifies 128 genetic variations that contribute to SZ

- would be 100% if it was genetic

- cannot be certain is not contributing in twin studies 

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Dopamine Hypothesis

Too much DP leads to onset of SZ.

Drugs that block DP receptor sites are effective in treating SZ. 

*Davis: high DP not in all SZ petients. Clazapine (dosnt block DP) is effective in treating SZ

- over simplistic and non-inclusive 

- ignores role of environment 

+ possibel to idirectly measure DP levels thru scanning

+ DP hypothesis has generted lots if reasearch and driven drug treatmets 

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Neural Correlates

Grey matter: grey matter deteriorates t leave vesivles in the brain of mush 

Amygdala Differences: Li- bilateral amygdala is less active in SZ patients 

- not all patenients show these differences 

- bio deterministic

+ Ho: by rescannign patients, brain differences increase over time 

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Family Dysfunction

Batesons double bind: contradictiry actions and words 

  • high levels of interpersonal conflic
  • difficulty communicating 
  • controlling of children

Stress is harmful as it realeses cortisol (activates fight or flight). Long term stress can lead to incresed chances of SZ

*Patino: large sample of children. Found family disfunction when family problems such as child abuse and overprotection were reported

*Tienari: high SZ risk adoptees living in either dysfunctional or normal families. 35% SZ in dysfunctinal compared 5%normal

- doesnt explain why some children in dsyfunctinal families dont  develope SZ

+ family therapy has been shown to be effective in achieveing more positive long term outcomes for patients, supporting theory

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Cogntive Explanation

Maladaptive thoughts cause SZ. INdividuals cannot process information so are mispercieved as voices. 

Hallucinations created: by mispercieving thoughts as being inserted in the head by someone else

Delusions created: by an 'alien control system

Negative symptoms comes from overwhelimg emotional dsitress, so individuals 'flatten' to deal w suprluss

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Drug Therapies - Typical


  • Strong
  • Sedative
  • 1st gen
  • Slows dopamine
  • Block D2 receptors
  • Reduce excitation
  • Reduce +ve symptoms
  • Erectile dysfunction
  • Weight gain
  • Haldol
  • Clorporzine
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Drug Therapies - Atypical

  • Weak
  • Non-sedative
  • 2nd gen
  • Acts on dopamine as well as seretonin
  • Effects -ve symptoms
  • Clozapine
  • Olanzapine
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Applies Ellis' ABC model to identofy faulty cognitions, goal setting and normalising their psychological experineces, then developing alternatuve assumptions. 

*Sensky: compared CBT to non-specific befreinding methods. Found same level of immidiate improvemnt, but in follow up, CBT maintained their improvemtn while non-specific had lost some benefits 

+ works well in combo w drug therapies 

+ requires skilled therapist who is experenced w working w SZ patients 

- no suitable for all patients (e.g. extremely aggitated patient)

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