schizophrenia

what is schizophrenia

• a type of psychosis, characterised by a disruption of cognition and emotion - affects perception of external reality.

• affects 1% of the population at some point in their life - peak in adolescence aged 25-30

4 main symptoms of schizophrenia

• hallucinations

• avolition

• delusions

• speech poverty

types of delusions

delusions are firm irrational beliefs

• reference - believe neutral messages are aimed or for you

• persecution (paranoia) - watched and spied on

• control - external locus of control

• grandeur - more able than u are

positive symptoms of schizophrenia

things added that the average person doesn’t experience

• delusions

• hallucinations

• disorganised speech - word salad

• disorganised behaviour (catatonic) - tense

negative symptoms of schizophrenia

deficits that the average person doesn’t experience

• avolition - inability to innate purposeful activity

• speech poverty - deduction in fluent speech

• affective flattening - absence of emotional expression

• anhedonia - inability to feel pleasure

criteria to be diagnosed with schizophrenia

• 2 or more symptoms for at least a month

• mild signs of disorder continuously for 6 or more months

what must you rule out when diagnosing schizophrenia

• autism/ communication deficits

• sustenance effects/ medical issues

• (manic)depression, schizoaffective disorder

what is classification

organising symptoms into categories based on which symptoms shared by sufferers

what is diagnosis

deciding whether someone has a particular mental illness using the classifications.

what is the DSM

Diagnostic and Statistical Manual of Mental Disorders

• current version is the DSM-5

what is reliability in terms of classification and/or diagnosis

How consistently clinicians come to the same conclusion using the criteria (test-retest reliability) and agree with each other (inter-rater reliability)

what is validity in terms of classification and/or diagnosis

How far the DSM measures what it says it does, and whether a diagnosis represents a clear, distinct condition

what problems affect classification and/or diagnosis

• symptom overlap

• gender bias

• cultural difference

• comorbidity

rosenhan's study on diagnostic systems

• covert participant observation across 5 states

• 8 fake patients reported hearing a voice making a "dull thud" (not a dsm-ii symptom)

• all diagnosed with schizophrenia and hospitalized

• inter-rater reliability was good, but internal validity was very poor

• raised significant ethical concerns for patients

• later told hospitals more fake patients were coming; 21% of real patients were labelled "pseudopatients" and released over 2 weeks, even though rosenhan sent 0 fake patients

evaluation issues in diagnostic systems

• inter-rater reliability can be swayed by subjective criteria eg poor cross-cultural agreement

• gender bias - loring et al. (1988) found 56% diagnosis rate for male vs 20% for female case studies

• comorbidity & symptom overlap makes precise diagnosis difficult

• ethical - misdiagnosis leads to wrong medication usage and can worsen patient conditions

explain cultural bias affecting diagnosis in schizophrenia

• researchers misreprent differnces in cultures

• use their socizl norms to decide

• can lead to overdiagnosis to those in different cuktures

explain gender bias affecting diagnosis in schizophrenia

• differences in men and women are misrepresnted

• alpha and beta bias can lead to under or over diagnosi

explain comorbidity affecting diagnosis in schizophrenia

• two or more illnesses occur tigetehr in the same operson

• explain gender bias affecting diagnosis in schizophrenia inked with ocd, did and depression

• if comorbid some docs may ignore some symtoms - different docs, same patient, diffferent diagnosis - reduced reliability

• two illnesses comorbid, suggests criteria for dianosing illnesses may be incorrect (may be the sme) - invalid?

explain symptom overlap affecting diagnosis in schizophrenia

• symtoms overlap with depression and ocd

• may diagnose wit different disorder - reduced reliability

• may diagnose wrong disorder - reduced validtu

evidence for cultural bias in schizophrenia diagnosis

COCHRANE

• conducted reviews of those diagnosed with sz in britain and caribbean

• rate of sz was similar

• 7x more likely for carabs to be diagnosed in the uk

• concluded it was due to cultural bias

evidence for gender bias in schizophrenia diagnosis

LORING AND POWELL

• gave male and female docs identifcal descriptions of patient

• varied whether patient was described as male or female

• when male - 56% diagnosed with sz

• when female - 20% diagnosed

• indicates alpha bias

evidence for comorbidity in schizophrenia diagnosis

BUCKLEY

investigated how many sz had comorbid mental disorders

• 50% had comorbid depressions

• 47% had an addiction

• 23% had ocd

• sz criteria may lack validity - non distinctive symptoms

evidence for symptom overlap in schizophrenia diagnosis

ELLASON AND ROSS

• compared symptoms of those with DID and sz

• found with DID had more sz symptoms than those with sz

• DSM diagnostic criteria may be too unclear to provide a reliable or valid diagnosis