Exam 4 - Schizophrenia Flashcards
Schizophrenia
- profound disruption of basic psychological processes; distorted perception of reality; altered/blunted emotion; disturbances in thought/motivation/behavior
- 2 major symptoms for 1 month, w/ signs for at least 6 months
Gender differences
- peak onset for F and M from 16-25
- more women experience their first episode >36 (hormonal changes like menopause)
Diagnostic criteria - positive symptoms
- delusions: unreasonable beliefs/ideations, held despite being proven wrong
- hallucinations: visual, mostly auditory sensations
- something that schizo pts have that we do not
Diagnostic criteria - negative symptoms
- disorganized speech: incoherent, word salad
- disorganized or catatonic behavior: lack of goal oriented behavior, unnatural behavior, catatonia
- blunted affect: lack of emotional response, lack of motivation
- these symptoms usually indicate a poorer prognosis
How were pts with schizo treated in the 1950s?
- majority were institutionalized
- most widely used treatment was a frontal lobotomy
- electroconvulsive therapy, lobotomy, restrainment
Heredity
- closer the genetic relationship, the higher the chance
- 48% chance in identical twins
Developmental errors associated w/ schizo
- higher occurrence of perinatal complications
- exposure to viral infections while in womb
- genetic vulnerability
Dopamine theory
higher levels of dopamine in pts with schizo
Structural brain abnormalities associated w/ schizo
- positive symptoms usually due to NT imbalances
- negative symptoms usually due to structural abnormalities like:
- enlargement of ventricles
- cerebral atrophy
- reduced volume in basal ganglia, temporal lobe, limbic areas
- disorganized neural structure
Functional abnormalities
- hypofrontality
- decreased blood flow in frontal cortex while performing cognitive tasks requiring planing and strategy
Effectiveness of treatment - law of thirds
- significant time hospitalized, failure to respond to medication
- respond well to medication
- improvement in symptoms, relapses and hospitalization, need assistance
Phenothiazines
- antipsychotics like thorizene
- antagonists of D2 receptors, and partial affinity for other dopamine receptor subtypes
What is the initial reaction to phenothiazines?
- increase in dopamine synthesis, and release of autoreceptors that are more sensitive to dopamine
Side effects of phenothiazines
- blockage of norepi receptors: dry mouth, low BP, tachycardia
- block muscarinic receptors: dyr mouth and eyes, dilated pupils, blurred vision, decreased sweating, memory impairment
- block D2 receptor: parkinsons symptoms, tardive dyskinesia
Tardive dyskinesia
motor tics
Nonphernothiazine antipsychotics
- haloperidol
- similar to phenothiazines, but not in structure
New generation (atypical) antipsychotics
- clozapine
- antagonize D1 and serotonin receptors
- help positive and negative symptoms
Pharmacodynamics of clozapine
- weakly competes with dopamine receptors - less incidence of tardive dyskinesia
- do not cause extrapyramidal side effects
Side effects of clozapine
- sedation, hyperglycemia
- most serious and rare side effect is agranulocytosis (deficiency of WBCs)
Risperidone
treatment of schizo in children and adolescents aged 10-18
Pharmacodynamics of risperidone
- blocks both D2 and serotonin 5-HT2a receptors
- competes w/ noradrenergic receptors
Amisulpride
- more effective in treating depression with psychotic symptoms
- not associated with hyperglycemia
Pharmacodynamics if amisulpride
- potent blocker of D2 and D3 receptors
- at low doses it does act on presynaptic autoreceptors
- does not block 5-HT2a receptors
Schizo pts have depressed numbers of ______ receptors in the ________ and ______________. What does this mean?
- NMDA
- thalamus
- hippocampus
- drugs that enhance glutamate activity might be more effective in treating negative symptoms and cognitive impairments than dopamine antagonist
Preclinical models of schizophrenia
- reaction to high doses of stimulants like amphet and cocaine
- in animals, high doses of amphet produces amphetamine induced stereotypy (sniffing, licking, gnawing)
- apomorphine administration in rodents causes hyperactivity
- failure to filter sensory stimuli they receive (sensory overload)
PCP induced psychosis
- preclinical model of schizo
- resembles acute episode of schizo
- disorientation, profound cognitive impairments, motor symptoms, paranoid delusions
Prepulse inhibition of startle in schizo
pts with schizo have trouble tracking with their eyes
- especially prominent in chilren
How effective if pharmacological treatment of schizo?
- 75% respond well
- no cure, but early detection and pharmacological treatment may slow or suspend progression
