schizophrenia Flashcards
(12 cards)
what are positive symptoms of schizophernia
hallucinations- unusual sensory experiences-hearing voices
delusions-irrational beliefs
what do reliability and validity refer to in terms of a diagnosis
reliability means theres a good consistency overtime between the individuals who are using the system to rate patients
validity means that a diagnostic system assesses what it claims to be assessing. if a patient is diagnosed with schizophrenia they must actually have the disorder.
what are the negative symptoms of schizophrenia
speech poverty- unable to speak
avolition-being unable to keep up with goal directed activity- lack of energy, poor hygeine- lack of persistence in work or education
what is co morbidity and symptom overlap
co morbidity is the occurance of two illnesses together which confuses diagnosis and treatment
system overlap is when two or more conditions share symptoms, questioning the validity of the classification
what is the a03 for psychiatric diagnosis
supporting evidence from rosenhan-arranged for 8 confederates to act as pseudopatients going to 12 different hospitals, the real pps were the hospital staff that didnt know about anything.when the pseudopatient arrived they complained about hearing voices saying empty hollow and thud. once on the ward, the pseudopatients stopped pretending symptoms,behaved normally and wrote observations. the staff diagnosed 11 pseudopatients with schizophrenia and one with manic depression. this shows due to symptom overlap the doctors cant correctly diagnose patients with ICD/DSM and thus the measure isnt reliable.they cant differentiate between schizophrenia and depression
counter-small sample size
what is the ao3 for diagnosis and classiciation
low reliability-inter rater reliability in the case of the diagnosis of schizophrenia is poor- chineaux asked 2 psychiatrists to independently diagnose 100 patients using both DSM and ICD criteria. inter rater reliability was poor with one psychiatrist diagnosing 26 with schizophrenia according to DSM and 44 to icd and the other diagnosing 13 according to DSM and 24 to icd. this shows poor reliability as researchers cant come to the same conclusion
lack of validity-criterion validity is a way of assessing if different assessment systems arrive at the same diagnosis, this is poor in the diagnosis of schizophrenia. chineaux schizophrenia is more likely to be diagnosed when using ICD instead of DSM.
a limitation is co morbidity-buckley et al concluded half the patients with schizophrenia have a diagnosis of depression or substance abuse. ptsd also occurs in schizophrenia . this shows diagnostic tools cant tell the difference between schizophrenia and depression
a limitation is symptom overlap-both schizophrenia and bipolar have positive symptoms like delusions and negative symptoms like avolition. this questions the validity of both the classification and diagnosis of schizophrenia
what is the genetic basis for schizophrenia
twin studies gottesman-48MZ 17DZ
family studies-gottesman if both parents had schizophrenia theres a 46% chance of getting it but if one parent had it theres a 16 % chance
adoption studies-tiernari studies112 adopted children who didnt have schizophrenic parents and compared them to 135 adopted children with schizophrenia parents. by the time they reached adulthood 10.3 with schizophrenic parents developed schizophrenia compared to 1.1 with no schizophrenic parents.
what is the dopamine hypothesis for schizophrenia
the original version of the dopamine hypothesis focuses on the possible role of high levels or activity of dopamine in the sub cortex
the recent versions have focused on abnormal dopamine systems in the brains cortex. Goldman-rakic et al identified a role for low levels of dopamine in the prefrontal cortex in the negative symptoms of schizophrenia
what are the neural correlates of negative symptoms
avolition involves the loss of motivation- motivation involves the anticipation of reward and certain regions of the brain. abnormality of the ventral striatum is involved in avolition
what are the neural correlates of positive symptoms
allen et al scanned brains of patients experiencing auditory hallucinations and compared them to a control group. lower activation levels in the superior temporal gyrus and anterior cingulate gyrus were found in the hallucination group
what is the a03 for the genetic basis
supported by gottessman and tiernari
mutation supports the genetic explanation-schizophrenia can take place in absence of family history-evidence comes from a study showing positive correlation between paternal age and risk of schizophrenia, increasing from 0.7 in fathers under 25 to 2 percent in fathers over 50
