Schizophrenia PDF

# Schizophrenia ## Prevalence * Very low (0.3%) ## Etiology * Most known for schizophrenia (not the spectrum but very close) ### 1. Genetic Contributions: * Family heritability - 46% (2 parents), 17% (1 parent) chance of development * Identical twins - have a higher percentage of development *...

# Schizophrenia ## Prevalence * Very low (0.3%) ## Etiology * Most known for schizophrenia (not the spectrum but very close) ### 1. Genetic Contributions: * Family heritability - 46% (2 parents), 17% (1 parent) chance of development * Identical twins - have a higher percentage of development * Overall 40-60% (80% for spectrum disorders) * Adoption studies - if biological parents have schizophrenia even if the child is adopted they have a high percentage of being diagnosed ### 2. Biochemical Factors (Dopamine) * Neurochemical circuit differences for schizophrenia. * Most accepted theory: Dopamine theory * Excessive Dopamine * Two Factor Theory: * Insufficient dopamine in the pre-frontal area * Excessive dopamine striatal areas (D2 receptor sites) ## Treatment ### 1. Dopamine Antagonists ## Contrary Evidence 1. Dopamine antagonist is not universally effective 2. Clozapine - weak dopamine antagonist is effective 3. Dopamine down regulates but does not change the symptoms immediately 4. Unable to reduce negative symptoms (positive symptoms are more effective) ## Biochemical Factors: Another Contributor of Schizophrenia * Glutamate theory - dysfunction in glutamate activity. * Why? GABA dysfunction or excessive dopamine * Underactivity at NMDA receptors * Too much DA activity results in too little glutamate. * Operates through NMDA receptors * PCP and "special K" create schizophrenic-like symptoms * #glutamate = excitatory system * Increases communication of neurotransmitters ## Brain Structure and Function: Contributor * Areas of the brain that have abnormalities * According to FMRI: * Less activity in frontal areas of the brain * Hypofrontality: low activity of the frontal lobe * Enlarged ventricles: fluid in the brain is larger (due to shrinking of grey matter) * Changes in brain structure are correlated to schizophrenia but it is unknown if they cause schizophrenia. * Possible: medications or lifestyle changes may cause the brain function changes. ## Contemporary Models ### 1. Neurodevelopmental * Dysfunction in early cortical development * Children with certain behaviours have a higher percentage of developing schizophrenia * Onset higher in adolescence when brain re-wiring ## Some Factors are * (Early at birth can see signs of schizophrenia) * Smaller head circumference * Slower to reach developmental milestones * Higher rates of left-handedness * Minor physical/facial anomalies ## Birth Complications * Premature birth * Hypoxia (insufficient oxygen) * Obstetric complications ## Fetus Complications * Physical stress of mother 1st trimester (effect on developing fetus) * Maternal exposure to flu and viruses 2nd trimester ## Theory of Microglia * Dysfunction of microglia * How? Microglia is overactive in frontal lobes and removes essential cells. * Microglia functions by GABA and glutamate. * **microglia = removed damaged cells, maintain other cells ## Neurodevelopmental Model * Diagram depicting a model of neuronal pathways and developmental stages relevant to schizophrenia; includes 38 key points regarding this model. ## Neurons Developing in Fetus: * Cortical development: growth in grey and white matter. * Diagram depicting cortical development, key points include a graph with changes in grey matter, white matter, cortical thickness and surface area, from week 20 of gestation through 8 years of age; 39 key points regarding this model. ## Multiple Hit Model * The process of developing schizophrenia due to various contributors. * Diagram depicting a model of the multiple hit model, including key events from conception to late adulthood, along with key points; includes 40 key points regarding this model ## Psychosocial Contributions * Diagram depicting a model of this process, key points, and a graph depicting the model, along with 40 key points regarding this model * Likelihood of recurrence, not cause * Stressful life events * Family processes * Study disapproved that a schizophrenia mother would impact the child * Psychotic child which treated return to home cause relapse. * Why? Parents who are * Hostile * Critical * Over controlling