schizophrenia Flashcards
schizophrenia definition
a severe mental disorder involving impaired insight and loss of contact with reality
two main manuals used for classification of mental disorders
DSM- diagnostic and statistical manual of psychiatric disorders- mostly used in US
ICD- international classification of diseases- used in europe
posotive symptoms of schizophrenia
hallucinations
delusions
hallucinations
bizzare unreal perceptions of the environment that are usually auditory but could be visual olfactory or tactile
delusions
bizzare beliefs that seem real to the person with schizophrenia but arent real
these can be paranoid
negative symptoms of schizophrenia
speech poverty
avolition
speech poverty
lessening of speech fluency and productivity
thought to reflect slowing or blocked thoughts
avolition
reduction of interests and desires as well as an inability to initiate and persist in goal directed behaviour
what are the differences in the DSM and ICD
DSM one posotive symptom must be presented for diagnosis
ICD needs two or more negative symptoms for a diagnosis
reliability in the role of classification and diagnosis of schizophrenia
every clinician must be confident a classification system is consistent- two different clinicians should be able to reach the same conclusion about one patient (inter rater reliability)
or the same clinician must reach the same conclusion at two different times with the same patient (test retest reliability)
how is validity an issue in diagnosis and classification of schizophrenia
validity- refers to the extent that a test/tool is measuring what it is intended to measure (as distinct from other disorders)
reliability and validity are interlinked because a test or measure of a behaviour or disorder cant be reliable if its not valid
use of criterion validity in psychiatric diagnosis
limitation of the diagnosis of schizophrenia is its validity- use criterion validity in psychiatric diagnosis
schizophrenia is either over or under diagnosed= low criterion validity
study- 100 clients- found 68 diagnosed with schizophrenia under ICD and 39 under DSM
co morbidity
if conditions occur together a lot of the time then this questions the validity of their diagnosis and classification as they may be a single condition
schizophrenia is commonly diagnosed with other conditions- half siagnosed with schizophrenia also had a diagnosis for depression or substance abuse
isse for classification of schizophrenia because it may not exist as a distinct condition q
gender bias in diagnosis
since 1980s men are more commonly diagnosed than women- 1:4 ratio
women may be less vulnerable than men due to genetic factors
more likely that women are under diagnosed because they have closer relationships and hence get support so women with schizophrenia function better than men
under diagnosis is a gender bias and means women may not therefore be recieving treatment services that may benefit from
culture bias in diagnosis of schizoprenia
limitation of schizophrenia is culture bias
symptoms especially hearing voices have different meanings in different cultures
afro carribean societies- hearing voices may be attributed to communication from ancestors
symptom overlap
limitation of sz diagnosis is symptom overlap with other conditions
both sz and biploar disorder involve posotive symptoms- delusions and negative symptoms- avolition
in terms of classification this suggests sz and bipolar disorders may be variatons of a single disorder
key points of sz
experienced by 1% of the population
more commonly diagnosed in men than women
more diagnosis in cities and working class people
cluster condition
syndrome- lots of symptoms adding together
biological explanations for sz
genetic basis of sz
neural correlated of sz
genetic basis of sz
family studies
cadnidtae genes
the role of mutation
family studies
confirmed that risk of sz increases in line with genetic similarity to a relative condition
what did Gottesman find
large scale study in 1991 and fiund if you have an auntie with sz you have a 2% chance of developing the disorder
if you have a sibling this increases to 9%
identical twin- 48%
strong support to genetic explanation of sz- importanbt to remember families share many aspects of environment
candidate genes
no single responsible genetic variation
number of responsible genes- sz is polygenic
most likely genes appear to be those that code for the neurotransmitter dopamine
different studies have identified different candidate genes so sz is considered to be aetiologically heterogenous- means different combinations of factors including genetic variation can lead to the disorder
what did Ripke find
compared the genetic make up of 37,000 people with sz diagnosis to the genetic makeup of 113,000 controls
found 108 separate genetic variations associated with increased risk of disorder
the role of mutation
sz can develop in individuals with no family history of the disorder
one explanation can be gene mutation in the DNA of a parent which can be caused by mutation or viral infection
posotive correlations found between paternal age (increased risk of sperm mutation) and sz where the risk has been found to increase from 0.7% with a father under 25 to 2% in fathers over 50
neural correlates of sz
the original dopamine hypothesis
the revised dopmaine hypothesisn
the dopamine hypothesis
theory developed when it was found that antipsychotics used to treat sz (that reduced da) caused symptoms similar to those of parkinsons disease- associated with low da
parkinsons sufferers given L-dopa to increase da levels developed sz symptoms
considered that sz may be the result of high da levels (hyperdopaminergia)
eg excessive D2 receptors in pathway from subcortex to Brocas area (responsible for speech) could explain symptoms of speech poverty and auditory hallucinations
high number of D2 receptors on recieving neurons results in more neurons firing and more frequently leading to hallucinations and delusions that are charachteristics of sz
the revised dopamine hypothesis
hypothesis updated in 1991 to include cortical hypodopaminergia (low DA in the brains cortex) eg low DA in the prefrontal cortex- responsible for thinking could explain the negative symptom of cognitive problems
suggested cortical hypodopaminergia leads o subcortical hyperdopaminergia so both high and low da in different regions of the brain lead to sz
version also includes psychological origins of the disorder in terms of individuals experience of stress and how this can make some people more vulnerable to cortical hypodompainergia and hence subcortical hyperdopaminergia
neural correlated of negative symptoms
avolition- involves loss of motivation/anticipation of reward which is associated with the ventral striatum area of the brain
abnormality here may be involved in development of avolition
research found lower levels of activity in ventral striatum of sz sufferers than in controls
a negative correlation therefore between activity levels in the vs and severity of symptoms
neural correlates of posotive symptoms
hallucinattions
lower activation levls in the superior temporal gyrus has been found in sz patients who had auditory hallucinations when they were given task of identifying speech as their own or that of others compared to activity levels of conrtols doing same task
therefore reduced activity in the superior temporal gyrus is a neural correlate of auditory hallucinations
what is a limitation of the dopamine hypothesis
evidence for central role of glutamate
post mortem and live scanning studies have consistently found raised levels of the neurotransmitter glutamate in several brain regions of people with sz
means an equally strong case can be made for the role of other neurotransmitters
psychological explanations for sz
family dysfunction
cognitive explanations
family dysfunction
double bind theory
expressed emotion
cognitive explanations
metarepresentation dysfunction
central control dysfunction
double bind theory
bateson 1950s
children who constantly recieve contradictory messages from their parents are more likely to develop sz
interactions prevent development of an internally coherent construction of reality in long term can create sz symptoms- flattened affect and withdrawal- avoloyion-negative
- dont know which to respond to
expressed emotion
negative emotional climate or a high degree of expressed emotions
a family communication style
family members talk about the psyciatric patient in a critical or hostile manner
in a way indicating emotional over investment/ over concern with the patient and their behaviour
a patient returning to a family with high EE is over 4 times more likely to relapse
family members talked more and listened less
causes stress beyond (already impaired) coping ability, caused by the negative emotional environment
the schizophrenogenic mother
Frieda Fromm Reichman
patients noted particular charachteristics of their mothers- cold rejecting controlling
creates family environments of secrecy and tension
later leads to distrust and paranoia later developing into delusions (persecution complex) and ultimately sz
dysfunctional thinking
focus on role of mental processes such as reduced thought processing in ventral striatum associated with negative symptoms and reduced processing of information in temporal and cingulate gyri associated with hallucinations
low level of info processing suggests impaired cognition
metarepresentation dysfunction
Frith identified two types of dysfunctional thought processes:
metarepresenttation is the cognitive ability to reflect on thoughts and behaviour allowing self insight to goals and intentions also to interpret behaviour of others
dysfunction of this would impair the ability to recognise our own actions and thoughts as belonging to ourselves
this explains hallucinations and delusions as being like thought insertion- having thoughts projected into the mind by others
central control dysfunction
second type of thought disorder identified by Frith is problems with ability to suppress automatic responses when carrying out deliberate actions resulting in speech poverty and thought eg sufferers experience thought derailment because every word triggers an association and an automatic response to that which cant be suppressed
evidence that supports the view of family dysfunction as an explanation for the development of sz
adoption study by Tienari 1994
adopted children with schizophrenic biological parents were more likely to become ill than children with non sz parents
suggests illness develops under appropriate environment conditions so genetic vulnerability isnt sufficient
limitation of family dysfunction as an explanation for sz
explanations lack support for the link between childhood trauma and sz
Liem 1974
measured patterns of parental communication in families with a sz child and found no difference compared to normal families
inconsistencies in research
effectivness of CBT as support for congitive explanations
symptoms of sz have origin in faulty cognition is reinfforced by the success of cognitive based therapies
effectiveness of CBT shown in national institute for health and care excellence review of treatment for sz
found evidence that when compared with antipsychotic medication cbt was more effective in reducing symptom severity and improving levels of social functioning
supports view that faulty cognitions have an important influence in development of sz
support for Friths central control theory
evidence from experiments using stroop test support friths central control theory
stroop test- ps have to name the font colours of colour words so have to supress the tendancy to read words aloud
compared 30 people with sz to 30 controls
as predicted by friths central control theory people with sz took over twice as long on average to name font colours- suggests the congitive processes of people with sz are impaired
takes a lot of cognitive processing
vbiological treatments for sz
typical antipsychotics
atypical antipsychotics
antipshycotic drugs
drugs used to treat symptoms of psychotic illness
they work by reducing dopamine activity in the brain
given tablet/syrup or may be an injection
not necessarily given all life or straight away
things may settle down and be weened off
some take all life time
nasty side affects
have such wide ranging side effects- people stop taking them-symptoms come back
