schizophrenia Flashcards
(39 cards)
what is schizophrenia
characterized by disordered thinking in which ideas are not logically related, faulty perception and attention, a lack of emotional expressiveness & disturbances in behaviours
DSM-5 criteria for schizophrenia
symptoms last at least 6 months + at least 1 month of active-phase/acute symptoms (1-3)
1. delusions
2. hallucinations
3. disorganized speech
4. disorganized (or catatonic) behavior
5. negative symptoms (diminished motivation or emotional expression)
functioning in work, relationships, or self-care has declined since onset
comorbidity of schizophrenia
substance use, suicide (12x more likely)
more likely to die from any cause than people in the general population
prevalence, gender & age of schizophrenia
lifetime prevalence: 1%
affects men slightly more often than women - men have slightly more severe symptoms
age: usually late adolescence or early adulthood (earlier in men)
- have several acute episodes of symptoms + less severe but still debilitating symptoms between episodes
positive symptoms (schizophrenia)
comprise excesses and distortions, and include hallucinations and delusions
delusions = beliefs contrary to reality and frimly held despite disconfirming evidence - several forms (5 types)
hallucinations = sensory experiences in the absences of any relevant stimulation from the environment - often more auditory than visual
6 types of delusions
- thought insertion = believing thoughts that are not your own have been placed in your mind by an external source
- thought broadcasting = believing your thoughts are broadcast or transmitted, so that others know what they are thinking
- external force = believing that an external force controls your feelings or behaviors
- grandiose delusions = an exaggerated sense of own importance, power, knowledge or identity
- ideas of reference = reading personal significance into the trivial activities of others – e.g. think that overheard segments of conversations are about them
- paranoia/persecutory: thinking they are being targeted or are in danger (most common)
hallucinations in schizophrenia
- hear their own thoughts spoken by another voice
- hear voices arguing or hear voices commenting on behaviour
- ppl who have auditory hallucinations – may misattribute their own voice as being someone else’s voice
greater activity in Broca’s & Wernicke’s area when ppl w SC report hearing voices = problem in connections between speech production & speech comprehension areas
negative symptoms of schizophrenia
consist of behavioural deficits in motivation, pleasure, social closeness and emotion expression
avolition
asociality
anhedonia
blunted effect
alogia
what is avolition (apathy)
lack of motivation & absence of interest or inability to do usually routine activites, including work or school, hobbies or social activities
what is asociality
severe impairments in social interactions
- may have few friends, poor social skills, and very little interest in being with other people
- when around others – may interact only superficially + appear aloof or indifferent to the interaction
what is anhedonia
a loss of interest in or a reported lessening of the experience of pleasure
consummatory pleasure: the amount of pleasure experienced in the moment or in the presence of something pleasurable
anticipatory pleasure: the amount of expected or anticipated pleasure from future events or activities
ppl w SC - appear to have a deficit in anticipatory pleasure but not consummatory pleasure
what is the blunted effect
a lack of outward expression of emotion – may stare vacantly, the muscles of the face motionless, the eyes lifeless
- refers only to the outward expression of emotion, not to the inner experience, which is not diminished at all
- ppl w SC report experiencing the same amount or even more emotion than people w/o
what is alogia
a significant reduction in the amount of speech
- may answer a question with 1 or 2 words + not likely to elaborate on an answer with additional detail
disorganized symptoms of schizophrenia
disorganized speech: problems in organising ideas in speaking so that a listener can understand
disorganized behavior: may go into inexplicable bouts of agitation, dress in unusual clothes, act in a silly manner, hoard food or collect garbage
- catatonia
family studies of causes of schizophrenia
relatives of ppl w SC – increased risk + risk increases as the genetic relationship becomes closer
- neg symptoms may have a stronger genetic component than other symptoms
- study - incidence of SC was highest for children who had two parents admitted for SC
show that genes likely play a role in SC, but relatives also share common experiences = influence of env cannot be disregarded in explaining the higher risks among relatives
what are the 2 stages in schizophrenia
predormal – deterioration in normal functioning, mainly pos symptoms
residual – pos & disorganized symptoms leave, neg symptoms stay
twin studies of schizophrenia
risk for MZ twins (44%) is greater than DZ twins (12%) - but still less than 100% = not solely genetic factors (env factors)
adoption studies of schizophrenia
found that adoptees whose birth mother had it were way more likely to be diagnosed even when adoptive mother didn’t
no adoptees whose birth mother didn’t have it were diagnosed
molecular genetics in schizophrenia
DRD2 gene: encodes a specific type of dopamine receptor called D2 - implicated in the treatment of SC
COMT gene: associated w cog control processes that rely on prefrontal cortex – ppl w SC have deficits in this
- is on chromo 22 where rare mutations associated with SC have been identified
CNV mutations: 3x more common in SC but also related to other disorder (e.g. autism)
dopamine theory in schizophrenia
ppl w SC have excessive dop activity - mainly associated w pos & dis symptoms
support: effective drugs reduce dop activity, amphetamines (amplify dop activity) produce SC symptoms in ppl w/o it & make them worse in ppl who do
criticism: even when dop receptors are blocked it can still take time for symptoms to decrease + theory is too simple to explain whole
serotonin in schizophrenia
newer drugs partially block D2 receptors, but also block the ST receptor 5HT2
ST neurons regulate dop neurons in the mesolimbic pathway = involved in schizophrenia
GABA in schizophrenia
dop neurons regulate activity of other neural systems such as GABA neurons in prefrontal cortex
= GABA transmission is disrupted in the prefrontal cortex of people with SC
glutamate in schizophrenia
low levels of glutamate have been found in the CSF fluid of ppl w SC
+ low levels of enzymes needed to produce glutamate
elevated levels of homocysteine (amino acid) – interacts with the NMDA receptor (glutamate receptor) in ppl w SC
enlarged ventricles in schizophrenia
some ppl w SC have enlarged ventricles = implies loss of brain cells
related to poor performance on neurocog tests, poor functioning prior to onset & poor response to medication
