intro to schizophrenia

definition of schizophrenia

a severe mental disorder where contact with reality and insight are impaired

what are the different sources to classify schizophrenia

• ICD-10 - at least 2 negative symptoms must be present

• DSM-5 - at least 1 positive symptom must be present 

what are positive symptoms + examples

additional experiences beyond those of ordinary existence

1. hallucinations = unusual SENSORY experiences, some relate to real life whereas others don’t - can be in relation to any sense

2. delusions = irrational beliefs (also known as paranoia) - make a person behave in a way that seems normal to them but irrational to others - may believe they’re under external control

what are negative symptoms + examples

loss of usual abilities and experiences

1. speech poverty = changes in patterns of speech - may be a reduction in quality or amount - speech disorganisation = changes of topic mid sentence (positive in DSM-5 not ICD-10)

2. avolition = ( or apathy ) finding it difficult to maintain goal-directed activity - reduced motivation - characteristics = poor hygiene, lack of persistence in work or education, lack of energy

strength - good reliability

• reliability = consistency

• different clinicians give the same diagnosis = high inter-rater reliability

• Osorio et al. reported high reliability for diagnosis of schizophrenia of 180 individuals using DSM-5

• inter-rater reliability was +97 and test-retest reliability was +92

Limitation - low validity

• Cheniaux et al. had 2 psychiatrists diagnose the same 100 people independently using ICD-10 and DSM-5

• 68 were diagnosed w SZ under ICD-10 and 39 under DSM-5

• suggests SZ is either over or under-diagnosed

counterpoint to low validity

• Osorio et al. showed there was high inter-rater reliability when 2 psychiatrists were using DSM-5

• suggests there is validity when using one diagnostic source

limitation - comorbidity

• SZ may actually not be a single condition

• many people with SZ are also diagnosed with depression or substance abuse

• suggests it may not exist as a single condition

limitation - gender bias 

• men have been diagnosed with SZ more than women since the 1980s 

• women may be less likely to have SZ OR they may be under-diagnosed because they have closer relationships and get more support 

• therefore women w SZ often function better than men 

• gender bias may mean women get less treatment 

limitation - culture bias

• in places like haiti - hearing voices may be seen as communicating with ancestors

• African-Caribbean british people are 9x more likely to be diagnosed than white people

• leads to an overinterpretation of symptoms in black British people

weakness - symptom overlap

• SZ and bipolar share positive symptoms - may not be 2 different conditions but variations of the same one

• means SZ is hard to distinguish and may not exist as a single condition

• classification and diagnosis are both flawed