Schizophrenia Flashcards
what is sz
a severe mental disorder that affects thought processes and ability to determine reality
roughly 1% of people worldwide suffer sz
most often diagnosed between 15 and 35
men and women are affected equally
many symptoms of the disorder and not everyone displays the same symptoms
sz symptoms can be split into two categories
negative and positive symptoms
what are positive symptoms
involve displaying of behaviours concerning loss of touch with reality
occur in short episodes with normal periods in between and respond well to medication
types of positive symptoms
hallucination
delusions
disorganised speech
grossly disorganised
positive symptoms - hallucinations
to do with senses, bizarre unreal perceptions of the environment that are usually auditory but may also be visual and tactile
positive symptoms - delusions
to do with beliefs, bizarre beliefs that seem real to the person but are not real, sometimes can be paranoid in nature, delusions can involve inflated beliefs of persons grandeur, may also experience delusions of reference when events in environment seem related to them
positive symptoms - disorganised speech
result of abnormal thought processes where individual struggles organising thoughts this shows in the speech, they might slip from one topic to another or their speech might sound like complete gibberish
positive symptoms - grossly disorganised
catatonic behaviour - includes inability or motivation to initiate a task or to complete it once started individuals may act or dress bizarrely
catatonic behaviour are characterized by a reduced environment to immediate environment
what are negative symptoms
appear to reflect a reduction or loss of normal functions occurring in chronic, longer lasting periods
tend to be resistant to medication
negative symptoms contribute to sufferers not being able to live normally
types of negative symptoms
speech poverty
avolition
affective flattening
anhedonia
negative symptoms - speech poverty
lessening of speech fluency and productivity reflecting slower thoughts, individual may produce fewer thoughts in a given time its not that they dont know them
negative symptoms - avolition
reduction of interests and desires and inability to initiate and persist goal-directed behaviour, not having contact with friends family is not avolition, avolition is specified as a reduction in self initiated involvement
negative symptoms - affective flattening
reduction in range and intensity of emotional expression includes facial expression, voice tone, eye contact, body language
patients may also show deficit in prosocial linguistic features such as interaction
negative symptoms - anhedonia
a loss of interest and pleasure in almost all activities or a lack of reactivity to normally pleasurable stimuli, physical anhedonia - inability to experience physical pleasure, social anhedonia is inability to experience pleasure from interpersonal situations
diagnosing
schizophrenia is diagnosed by using classification systems that include lots of mental disorders, grouped in terms of their common features
diagnostic criteria for sz (DSM-V)
two or more of the following, present for a significant portion of time during a one-month period, at least one of the symptoms must be 1,2 or 3
1. delusions
2. hallucinations
3. disorganised speech
4. completely disorganised/ catatonic behaviour
5. negative symptoms
extra - level of functioning has been affected in a major area of life
ICD and DSM differences
ICD requires only 2 or more negative symptoms
DSM requires at least one positive symptom and one other symptom
reliability
can be replicated/ standardised
consistent over time, assuming symptoms dont change
different Dr’s diagnose same person with same thing, inter-rater reliability
validity
you’ve diagnosed them with sz and they actually have it
Rosenhan (1973) - highlights unreliability of diagnosis
normal people presented themselves to psychiatric hospitals in the US claiming they heard an unfamiliar voice in their head saying the words empty, hollow and thud
they were all diagnosed as having schizophrenia and admitted. throughout their stay none of the staff actually recognised they were normal, Rosenhan had to go and collect them himself
in a follow up study Rosenhan warned hospitals of his intention to send out more pseudo patients, this resulted in a 21% detection rate, although Rosenhan didnt actually send anyone
reliability in diagnosis
diagnostic reliability means that a diagnosis of sz must be consistent and repeatable
a single clinician needs to be able to reach the same conclusion at two different points in time
different clinicians must reach the same conclusions as each other
inter-rater reliability
this is measured using a kappa score, a score of 1 means perfect inter-rater reliability, a zero indicates zero agreement
a kappa score of 0.8 or above is generally considered good
in the 2013 DSM field trials the diagnosis of sz had a kappa score of 0.43 which is low inter-rater reliability
cultural differences in diagnosis - us and uk
the reliability of diagnosis in sz is further challenged by the finding that there is a massive variation between countries
Copeland (1971) gave 134 US and 194 British psychiatrists a description of a patient, 69% of the US psychiatrists diagnosed sz but only 2% of the British psychiatrists gave the same diagnosis this study doesnt have temporal validity though
A03 - reliability - cultural and racial differences
research has established cultural and racial differences in the diagnosis of sz
research suggests there is a significant variation between countries when it comes to diagnosing sz e.g. Harrison et al (1984) research suggested that those of Afro-Caribbean origin were over-diagnosed with sz, by white doctors in Bristol because of their ethnic background, positive symptoms like hallucinations are more acceptable in African cultures because of cultural beliefs in communication with ancestors, and therefore people are also more ready to talk about these experiences
A03 - reliability - lack of inter-rater reliability
despite revisions to the DSM still little to suggest reliability of diagnosis has improved, Whaley (2001), inter-rater reliability correlations as low as 0.11
A03 - reliability - Cheniaux (2009)
had two psychiatrists independently diagnose 100 patients using both DSM and ICD criteria, inter-rater reliability was poor, with one diagnosing 26 according to the DSM and 44 according to the ICD, the other psychiatrist diagnosing 13 with the DSM and 24 with the ICD
criterion validity
does the criteria/ measure actually describe sz
concurrent validity
do the findings of a new measure match findings of established measure
example of poor criterion and concurrent validity
looking at the figures in cheniaux (2009), sz is more likely to be diagnosed with the ICD than the DSM, so it is either over-diagnosed with the ICD or under-diagnosed with the DSM, either way this is poor criterion and concurrent validity
A03 - validity - gender bias
Loring and Powell (1988) - 290 male and female psychiatrists read nameless patient notes, asked to offer diagnosis based on standard criteria
when described as males or no gender information given, 56% of clinicians gave sz diagnosis, when described as females, 20% of clinicians gave sz diagnosis
gender bias not evident in female clinicians
so gender of patients and gender of clinicians important
A03 - validity - co-morbidity
common in patients with sz
comorbidity describes people who suffer from two or more mental illnesses, at one time
for example sz and depression are often found together, this makes it more difficult to confidently diagnose sz, comorbidity occurs because the symptoms of different disorders overlap
for example, major depression and sz both involve very low levels of motivation, this creates problems of motivation, this also creates problems of validity
A03 - validity - differences in prognosis
prognosis tells us if something is curable, what is it what the treatment will be, what are the next steps
no evidence that patients share the same outcomes post diagnosis
20% recover to previous level of functioning
10% significant and lasting improvement with intermittent relapses
this is a problem because it means that our definition of sz might be wrong and our classification of sz might also be wrong
biological explanations of sz
neural correlates, genetic factors
neural correlates - enlarged ventricles - Johnstone et al (1976)
used ct scans to study MZ twins and saw a clear size difference in the cerebral ventricles of the sz twin compared to the non-sz twin
the cerebral ventricles provide supporting fluid of the brain and keep everything in place by creating internal pressure. if there is damage to the brain and parts of it die then the ventricles will enlarge to fill the space left, so ventricular enlargement is often a good indicator of brain damage
neural correlates - ventral striatum, low activity - Juckel et al (2006)
measured activity levels in the ventral striatum in sz and found significantly lower levels of activity than observed in healthy controls, moreover they observed a negative correlation between activity levels in the ventral striatum and the severity of the negative symptoms
the ventral striatum is believed to be involved with the anticipation of a reward this anticipation is linked to feelings of motivation and avolition
neural correlates - dopamine hypothesis
excess of dopamine causes sz
original version of the hypothesis focused on possible role of high dopamine levels (hyperdopaminergia) in central areas of the brain like Broca’s area associated with speech poverty and hallucinations
in 1991 revised hypothesis says hypodopaminergic in the cortex (particularly pre-frontal cortex), recent version focused on abnormal dopamine systems in the brain subcortex, study found low levels of dopamine in the pre frontal cortex this links to negative symptoms of sz
both explanations are important
strength of dopamine hypothesis - amphetamines
amphetamines this is a dopamine agonist, this stimulates nerves cells containing dopamine causing the synapses to be flooded - large doses of the drug can cause hallucinations and delusion of a schizophrenic episode
increasing dopamine in some people increases hallucinations and delusion therefore bringing sz symptoms in non-sz patients
limitation of dopamine hypothesis
Noll (2009) claims there is strong evidence against both the original and revised dopamine hypothesis
he argues that antipsychotic drugs do not alleviate hallucinations and delusions in about 1/3 of people experiencing these symptoms, Noll also points out that, in some people, hallucinations and delusions are present despite levels of dopamine being normal
so there must be another factor causing the hallucinations and delusions