Schizophrenia descriptions Flashcards
Positive symptoms-
Negative symptoms-
-in excess of normal functions
-reduction or loss of normal function
Positive symptoms examples
-Hallucinations- unreal perception of environment, can be visual/auditory, olfactory(smell)/tactile
-Delusions- unreal beliefs eg thinking people will harm you, paranoia, delusions of grandeur (false impression of own importance eg. thinking you’re jesus)
-Disorganised speech- going on tangents, difficult to follow, word salads
-Grossly disorganised catatonic behaviour- increase in abnormal behaviour, decreased reaction to immediate environment
Negative symptoms examples
-Speech poverty (alogia) - lessening of fluency, less words produced in given time
- Avolition- reduction in goal directed behaviour eg. staying in bed all day
-Affective flattening- don’t express emotions, no body language, monotone
-Anhedonia- no pleasure from things they used to enjoy
Diagnostic reliability
-diagnostic reliability- diagnosis must be repeatable eg. clinicians reach same conclusion at 2 different times( test retest) or different clinicians reach same conclusion (inter rater reliability)
Cultural differences in diagnosis
Copeland
-gave US and british psychiatrists a description of patient. 69% US diagnosed with Sz, 2% british diagnosed with Sz.
Luhrman
-interviewed 60 adults with Sz from india, ghana and US. Africans and Indians described their voices as positive, playful, offering advice. Us described voices as violent, hateful
-Sz has lack of consistent characteristics
Problems with DSM-V
-hoped it would be a standardised method however behaviour is open to interpretation
-subjective
eg Rosenhan tested reliability and validity of DSM
-Rosenhan + 7 others entered hospitals saying their hearing voices
-once admitted, they acted as normal patients
-all were admitted to hospitals and later released with a diagnosis of Sz in remission
-found 71% of the time, Drs ignored when pseudo patients asked questions
-shows reliability of DSM but lack of validity as didn’t actually have Sz
Gender bias in diagnosis
Gender bias in diagnosis
-occurs when the accuracy of diagnosis is dependent on gender
-can be caused due to gender biased criteria, or clinicians having stereotypical beliefs
-Broverman found US clinicians equated mentally healthy adult behaviour with mentally healthy male behaviour, therefore women perceived less mentally healthy
-Longenecker found men diagnosed more often then women as female typically function better due to better interpersonal functioning that masks symptoms, making case seem too mild to diagnose
Symptom overlap- validity
Symptom overlap
-many symptoms found in depression, bipolar
-Ellason + Ross found people with dissociative identity disorder (DID) have more Sz symptoms then people diagnosed
-people with Sz often diagnosed with one other disorder
Co-morbidity - validity
-extent that 2 or more conditions occur at same time
-such as substance abuse, anxiety, depression
-Buckley found co-morbid depression occurs in 50% of patients
-OCD and Sz are both rare, but appear together very often
-eg. Swets- meta analysis found 12% of Sz fulfilled criteria for OCD
-when conditions appear together, it questions validity of diagnosis as might be one condition not 2
Validity in diagnosis
-gender bias
-symptom overlap
-co-morbidity
Genetic description
Family- tendency for Sz to run in families, as genes passed to generation. Chance of Sz in pop is 1% but more relatives with Sz more likely to have Sz eg. 2 parents with Sz child 46% likely to have Sz
Twin-Gottesman, 40 twin studies found 48% concordance MZ and 17% DZ. Concordance rate of MZ was also higher even when brought up apart
Adoption studies- Tienari, finland, 164 adopted children with mother with Sz 7% had Sz, 197 control without Sz mother 2% developed Sz
Biological explanations
-genetic
-dopamine hypothesis
-neural correlates
Dopamine hypothesis
-Sz have high number of D2 receptors resulting in more dopamine binding
-people with parkinson’s take drug L-Dopa top to increase dopamine and have found to develop Sz like symptoms
2 sources of evidence for role dopamine
Drugs increase dopaminergic activity eg. amphetamine- dopamine agonist- stimulates nerves containing dopamine increasing levels of This causes hallucinations and delusions
Drugs decrease dopaminergic activity eg. antipsychotic drugs act as dopamine antagonists- block dopamine’s action therefore eliminating symptoms eg hallucinations or delusions
Revised dopamine hypothesis
David and Kahn
-positive symptoms due to excess dopamine in subcortical areas of brain
-negative symptoms due to deficit of dopamine in prefrontal cortex
evidence: Patel, PET scans found lower levels dopamine in prefrontal cortex of people with Sz
Neural correlates
-asses which area of the brain is active
-both positive and negative symptoms have neural correlates
-identified using fMRI
-eg. group all have auditory hallucinations compare to group that don’t, if an area in brain is different can conclude that part of the brain is causing the auditory hallucinations
-ventral striatum is neural correlate for negative symptoms
-superior temporal gyrus + anterior cingulate gyrus are neural correlates for auditory hallucinations