Schizophrenia Flashcards
Main Criteria for Schizophrenia diagnosis
2 of the following for one month period: Delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behaviour, negative symptoms
Level of functioning in work, interpersonal relations, or selfcare is below the level acheived prior to onset
Continuous signs of disturbance in lsat 6 months
Schizoaffective disorders have been ruled out
Postive Symptoms
Mental phenomena that don’t happen in healthy people
Delusion: beliefs that are untrue or don’t make sense
Hallucinations: visual, auditory perceptions without sensory cause
Negative symptoms
Lack of mental phenomena that happen in healthy people
Blunted emotional responses
Impoverished content of thought and speech
Reduced social motivation
Cognitive abnormalities
Impaired working memory and executive function
impaired source monitoring - tendency to misattribute own actions and thoughts to external causes, confusing imagination and real memory
Loosening of associations: rambling on, losing initial train of thought or purpose of speaking
Common risk factors of schizophrenia
Hereditary risk in monozygotic twins
Genetics, urban environments, cannabis or stimulant use, 1st/2nd trimester maternal infection/malnutrition, paternal age 35 years, perinatal complications
Structural brain changes
Widespread decrease in brain grey matter (frontal and temporal cortices)
Thinning of dorsolateral PFC - this volume loss results in enlarged ventricles. Due to reduction in cell processes
PFC: loss of dendritic spine density, fewer GABAergic interneurons
Hippocampus: atypical layering structure, atypical neuron shape
Functional brain changes
Hypoactive frontal and temporal lobes (including hippocampus)
Diminished activity
Non-pharamcological treatments for schizophrenia
CBT: management of both positive and negative symptoms, combined with medication
Pharmacological treatments
Antipsychotic drugs:
typical: acting on dopamine. movement disorders side effects
Atypical: act on dopamine, serotonin and other receptors, metabolic side effects
Mainly for positive symptoms
Dopamine theory general idea
Schizophrenia caused by overactive dopamine receptors
Evidence for dopamine theory
Brains of individuals with parkinsons have marked dopamine depletions, and antipsychotic drugs produce similar symptoms of schizophrenia
Drugs that increase dopamine produce symptoms of schizophrenia
Antipsychotic drugs that block dopamine receptors work better for shizophrenic patients
Problems with Dopamine theory
Atypical psychotic drugs produce a wide variety of changes in the brain, just as good as typical drugs
2-3 weeks for antipsychotic drugs to work but effects on dopamine receptors are immediate
most patients show no significant improvement to their first antipsychotic given
Glutamate hypofunction theory
Phencyclidine and ketamine inducing negative symptoms and psychosis acting antagonistically on NMDA receptors
Evidence for glutamate hypofunction theory
Less GABAergic transmission = less inhibition for downstream cells.
Too much activity downstream: unbalanceed excitation vs inhibition
Cause of glutamate hypofunction?
NMDA synapse in teens/twenties: dysregulated plasticity. excessive immune activation and overly aggressive synaptic pruning
