Schizophrenia Flashcards
ICD-10
Negative symptoms - avolition
DSM-5
Positive symptoms - delusions; hallucinations
Paranoid schizophrenic
Characterised by powerful delusions and hallucinations
Hebephrenic schizophrenic
Primarily negative symptoms
Catatonic schizophrenic
Disturbance to movement (leaving sufferer immobile or overactive)
Positive symptoms
Hallucinations: unusual sensory experiences
Delusions: irrational beliefs and paranoia
Negative symptoms
Avolition: loss of motivation > lowered activity levels
Speech poverty: reduced frequency and quality of speech
AO3 Diagnosis and classification: Symptom overlap
W
Possible overlap between symptoms of schiz and other conditions
E.g., schiz and bipolar involve positive symptoms
-> misdiagnosis
AO3 Diagnosis and classification: Cultural bias
W
African-Americans & English of Afro-Caribbean origin = more likely than white people to be diagnosed
Rates in Africa = not high
AO3 Diagnosis and classification: Gender bias
W
Longenecker - since 80s, men have been diagnosed with schiz more than women
More genetically vulnerable?
Or, gender bias: females typically function better
AO3 Diagnosis and classification: Reliability
W
Cheniaux = 2 psychiatrists diagnose 100 patients using DSM and ICD.
Inter-rater reliability = poor
One psychiatrist > 26 schiz DSM, 44 ICD
Other > 13 DSM, 24 ICD
Genetic basis of schiz (Gottesman)
Runs in families
Gottesman found that as genetic similarity increases, so does the probability of sharing schiz
Individual genes
Believed to be associated with risk of inheritance
Schiz = polygenic
Requires a number of factors to work in combo
Schiz = aetiologically heterogenous
Different combos of factors can lead to the condition
Dopamine hypothesis: neurotransmitters
Important in the functioning of several brain systems that may be implicated in the symptoms of schiz
Hyperdopaminergia in the subcortex
Original version of DH focused on role of high levels in subc, e.g., high levels in Broca’s may be associated w poverty of speech
Hypodopaminergia in the cortex
More recent versions of DH focus on abnormal dopamine systems in the brain’s cortex
Identified role for low levels in the prefrontal c (thinking/decision-making impact)
Neural correlates of negative symptoms
Avolition - anticipation of a reward. Certain regions of the brain believed to be involved.
Juckel: measured activity lvls in ventral striatum; found lower levels.
Neural correlates of positive symptoms
Allen: scanned brains of patients w auditory hallucinations > compared to control group as they identified pre-rec speech as theirs or others.
Lower activation levels in superior temporal gyrus & anterior cingulate g; more errors
Bio explanations AO3: Correlation-causation problem
Does the unusual activity in a region of the brain CAUSE the symptom?
E.g., correlation between lvls of activity in ventral striatum & neg sy. Also possible that neg sy mean less info passes through (reduced activity)
Bio explanations AO3: Reductionist
Ignores psychological factors; only focuses on bio aspects. E.g., doesn’t consider schiz mother/double-bind theory
Bio explanations AO3: Ev for genetic susceptibility
Adoption studies - show children of schiz sufferers are still at a heightened risk of the disorder if adopted into families w no history
Bio explanations AO3: RWA
Explanations let to findings of drug therapies (typical/atypical antipsychotics to reduce intensity of sy) E.g, Clozapine
