schizophrenia basics

what are the positive symptoms

• hallucinations

  • see, hear, feel things that aren’t there

• delusions

  • irrational beliefs

  • believe you’re an important political figure, royal etc (delusions of grandeur)

  • believe someone is out to get you, government, etc (delusions of persecution)

what are the negative symptoms

• speech poverty

  • reduction of amount/quality of speech

• avolition

  • lack of motivation

  • find it hard to keep up with goal directed activities 

what is the general theory behind the reason for positive and negative symptoms 

• positive = too much dopamine in the brain

• negative = not enough dopamine in the brain

DSM 5 2013 classification

• looks at symptoms as a spectrum

  • not subtypes like it used to be

• 2+ key symptoms

  • positive/negative

• level of functioning below where it was

• 6+ months

• symptoms can’t be explained by another condition or substance

ICD 10

• 7 subtypes

• to be diagnosed

  • 1+ key symptom or 2+ other symptoms

  • 1+ month

  • symptoms can’t be explained by mood disorders, developmental disorders, or a substance

reliability of DSM 5?

• high reliability

  • Osorio et al 2019 found pairs of interviewers achieved inter-rate reliability rates of +.97 and test-retest reliability of +.92 in 180 people

define inter-rater reliability

• different clinicians diagnose someone with the same condition

define test-retest reliability

• the same clinician reaches the same diagnosis on 2+ occassions

Cheniaux et al 2009 DSM vs ICD study

• asked 2 psychiatrists to assess the same 100 clients using ICD 10 and DSM 4

  • 68 diagnosed under ICD

  • 39 diagnosed under DSM

    • under/over diagnose depending on the system used

• DSM 5 and ICD 11 are more similar so have greater validity

define co-morbidity

• when one or more disorder occurs at the same time

• makes it hard to tell if a person has 1 disorder or 2

  • a limitation of schizophrenia diagnosis

  • Buckley et al said 50% of people with it also have depression, 47% with substance abuse, and 23% with OCD

define symptom overlap

• 2+ conditions share many symptoms 

• schizophrenia and bipolar share many positive and negative symptoms 

  • could mean that the 2 conditions are variations of one condition

  • both involve obsessions and paranoid fears

gender bias in diagnosis

• men diagnosed more since the 80’s

• women may be less vulnerable due to genetic and biological factors 

• cotton et al 2009

  • women are less likely to get diagnosed because they get support from close relationships with other women

culture bias in diagnosis

• afro-caribbeans in the UK are 10x more likely to be diagnosed 

• hearing voices has a different meaning across cultures

• genetic vulnerability is possible but it’s more likely a culture bias