• Psychotic disorder as it often involves a loss of contact with reality and self insight.


  • Positive symptoms - delusions (paranoid - something is after them or grandeur - they have some sort of power/authority), hallucinations (normally hearing voices but can also see, smell, taste and feel things that aren't there), disorganised speech (speaks in ways that are incomprehensable).
  • Negative symptoms - avolition (lack of motivation), aogia (speech poverty), affective flattening (lack of emotions).

Reliability and validity of diagnosis:

  • DSM-V - at least two symptoms for a month or longer, at least one must be positive.
  • ICD-10 - two or more symptoms including negative ones. Paranoid (delusions, hallucinations, negative symptoms), hebephrenic/disorganised (aimless/disorganised behaviour, rambling, incoherent speech), catatonic (motor abnormality, unmoving strange posture, flailing limbs).
  • Rosenhan - 8 confederates as pseudopatients to 12 differnet hospitals, real particpants were hospital staff. Confederates said they were hearing voices. False names, occupations and symptoms but real life histories. Behaved normally on wards and wrote observations. Only discharged when they convinced staff they were sane. 11 diagnosed with SZ and 1 with manic depression. Sanity never dtected by staff. Nurses reported no abnormal behaviour. Average stay of 19 days. All discharged with diagnosis of SZ in remission . 35 patients detected sanity. Unreliable as as staff can't always distinguish sanity from insnaity. Less risky to diagnose as sick than vice versa. Normal behaviour interpreted in context of illness. Normal seen as abnormal because to support idea of mental illness. Shows DSM was flawed.
  • DSM-V and ICD-10 have different criteria which is unrelaible.
  • Low validity as it is based on interpretaion of psychiatrist.
  • Symptom overlap as many conditions have the same symptoms.
  • Co-morbidity as the patient may have more than one mental illnesss which may be treated as a single one. Half of SZ patients are depressed or have substance abuse.
  • Culture bias as positve symptoms such as hallucinations may not be abnormla in other cultures. DSM-V and ICD-10 are based on Western cultures which is ethnocentric.
  • Gender bias - study by Loring and Powell. 290 male adn female psychiatrists to diagnsoe patients. When gender was given as male or not stated 56% diagnosed with SZ but when told they were female it dropped to 20%. Gender bias didn't seem to be evident among female psychiatrists. Women are better at hding symptoms. Men suffer more negative symptoms. Affects validity.

Biological explanations:

  • Genetics - SZ runs in families. High risk of developing it. No one gene is responsible. Likely a combination. Gottesman studied 40 twins. Concordance for MZ twins was 48% but DZ twins was 17%. Recent blind studies have found lower concordance rates for MZ twins. Still shows genetic oresispostion. Gottesman also found if both parents had SZ there was 46% chance of you having it, 13% chance with one parent and siblings had 9% chance. Adoption studies with biological mothers iwth SZ had concordance rates of 6.7% compared 2% with children who didn't have SZ parents.
  • Dopamine hypothesis - excessive amounts of dopamine…


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