Schizophrenia Flashcards
What is schizophrenia?
a severe mental disorder where contact with reality and insight are impaired
How are diagnosis and classification are interlinked?
in order to diagnose a specific disorder, u need to distinguish one disorder from another by identifying symptoms that occur together and classifying that as one disorder
What are the 2 major systems for the classification of of mental disorder ?
World health organisation international classification of disease (ICD-10)
American psychiatric association diagnostic and statistical manual diction 5 (DSM-5)
To diagnose schizophrenia:
a) what does the DSM-5 state
b) what does the ICD-10 state?
a) DSM-5: 1” positive symptom” must be present
b) ICD-10: 2 “negative symptoms” must be present
what are the positive symptoms of sz?
hallucinations
delusions
what are hallucinations?
unusual sensory experiences:
some are related to events in environment whereas others bear no relationship to what the senses are picking up from the environment
e.g voices heard either talking to or commenting on a person
can be experienced in relation to any sense
e.g person sees distorted facial expressions or occasionally people/animals that are not there
what are delusions?
(paranoia) irrational beliefs
common ones: being an important historical, political or religious figure, being persecuted e.g by government/aliens, having superpowers, may believe they are under external control
ppl w delusions more likely to be victims but some lead to aggression
what are negative symptoms of sz?
(involves loss of usual abilities)
speech poverty
avolition
what is speech poverty?
(Seen as a negative symptom bc of emphasis on reduction in the amount n quality of speech, somet8mes accompanied by a delay in persons verbal responses during convo )
more emphasis is now placed on SPPECH DISORGANISATION (speech becomes incoherent or speaker changes topic mid sentence)
classified as a positive symptom in DSM-5 but remains a negative symptom
what is avolition (apathy)?
described as finding it difficult to begin or keep up with a goal-directed activity
ppl w sz have sharply reduced motivation to carry out range of activities
andreasen (1982) identified 3 signs of avolition:
poor hygiene n grooming, lack of persistence in work/education, lack of energy
eval: how is it a a strength that the diagnosis of sz has good reliability?
reliability has now improved: osorio et al. (2019) reported excellent reliability for diagnosis in 180 individuals using DSM-5. pairs of interviewers achieved inter-rater reliability (when diff clinicians reach the same diagnosis for same individual) of +9.7 and test-retest reliability (when same clinician reaches same diagnosis for same individual on 2 occasions) of +9.2
means we can be reasonably sure that the diagnosis of sz is constantly applied
eval: how is it a limitation that the sz diagnosis has co-morbidity with other conditions?
if conditions occur together, questions the validity of diagnosis and classification as it may be a single condition
sz is common,y diagnosed w other conditions e.g depression/substance abuse
problem for classification s sz may not exist as a distinct condition
prom for diagnosis as at least some pp, w sz may have unusual cases if conditions e.g depression
eval: how is it a limitation that there is an existence of gender bias?
since 1980s men diagnosed more than woman ( 1.4:1 fischer n buchanan 2017)
possible explanation: women are less vulnerable than men bc of genetic factors
women under diagnosed as they have close relationships and get support (cotton et al. 2009) leading to women w sz functioning better than men
underdiagnosis = gender bias and means women may not be receiving treatment and services that might benefit them
eval: how is it a limitation that there is an existence of culture bias?
some symptoms of sz e.g hearing voices, have diff meaning in diff cultures (in Afro-caribbeans, may mean communication from ancestors)
culture bias as diagnosis if clients is done by psychiatrists from a diff cultural background, appears to lead to an over-interpretation if symptoms in black British people (Escobar 2012)
means Afro-Caribbean people may be discriminated against by a. Culturally-biased diagnostic system
eval: how is it a limitation that there is a symptom overlap with other conditions?
overlap between sz n other conditions e.g bipolar disorder : both involve positive symptoms e.g delusions and negative symptom e.g avolition
in terms of classification: suggests sz and BPD may be a variation of a single condition rather than 2 different ones
in terms of diagnosis it means sz is hard to distinguish from BPD
how have family studies confirmed the risk of sz increases in line w genetic similarity to a relative w sz?
gottesman’s (1991) large-scale family study found
e.g person w aunt w sz has a 2% chance of developing
increases to 9% if individual is a sibling and 48% if they are a twin
how is sz polygenic?
a number of different genes are involved (genes coding for neurotransmitters e.g dopamine)
what did the study conducted by ripke et al. (2014) show?
combined previous data from genome wide studies
genetic makeup of 37k people w diagnosis of sz were compared to that of 113k controls
found 108 separate genetic variations were associated w slightly increased risk of sz
shows sz is AETIOLOGICALLY HETEROGENEOUS (bc diff studies have identified diff candidate genes i.e diff combos of factors including genetic variation can lead to sz)
how can sz have genetic origin in the absence of a family history of the disorder?
explanataion: mutation in parental DNA caused by radiation, poison, viral infection
evidence for mutation comes from positive correlations between paternal age (associated w increased risk of sperm mutation) and risk of sz, increasing from 0.7% w fathers under 25 to over 2% in fathers over 50 (brown et al. 2002)
what was the original dopamine hypothesis?
based on discovery that drugs used to treat sz (antipsychotics which reduce dopamine) caused symptoms similar to those in people w parkinsons disease (associated w low dopamine levels)
therefore s must be result of high dopamine levels in subcortical parts of the brain
eval: how is it a strength that the genetic explanation has a strong evidence base?
gottssman: shows risk increases w genetic similarity
adoption studies e.g tienari et al. (2004): shows biologiczl children of parents w sz are at heightened risk even if they grow up in an adoptive family
shows people are more vulnerable to sz as a result of their genetic makeup
eval: how is it a limitation that there is evidence to show that environmental factors also increase the risk of developing sz?
environmental factors include biological (birth complications and smoking THC rich cannabis in teenage years) and psychological influences (childhood trauma, leaves ppl more vulnerable to mental health problems)
morkved et al. (2017) 67% of ppl w sz and related psychotic conditions reported at least one childhood trauma as opposed to 38% of a matched group w non-psychotic mental health problems
MEANS GENETIC FACTORS ALONE CANNOT PROVIDE A COMPLETE EXPLANATION FOR SZ
eval: how is it a strength that dopamine is involved in sz?
- amphetamines increase D and worsen symptoms in people w sz and induce symptoms in people without (curran et al. 2004)
- antipsychotic drug reduce D activity and reduce intensity of symptoms (tauscher et al. 2014)
- candidate genes act on production of D/D receptors
strongly suggests that D is involved in symptoms of sz
eval: how is it a limitation of the dopamine hypothesis that there is evidence for central role of glutamate?
post-mortem and live scanning studies have consistently found raised levels of the neurotransmitter glutamate in severl brain regions of people w sz (McCutcheon et al. 2020)
several candidate genes for sz are believed to be involved in glutamate production or processing
MEANS THAT AN EQUALLY STRONG CASE CAN BE MADE FOR A ROLE FOR OTHER NTS
