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Schizophrenia. Onset can be slow or sudden Typically exists chronically Affects ~1% of population Diagnosis must have at least two symptoms for more that 1 month. Schizophrenia Symptoms. Positive Symptoms (abnormal states) hallucinations (auditory, visual) delusions (grandeur, persecution)
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Schizophrenia Onset can be slow or sudden Typically exists chronically Affects ~1% of population Diagnosis must have at least two symptoms for more that 1 month
Schizophrenia Symptoms • Positive Symptoms (abnormal states) • hallucinations (auditory, visual) • delusions (grandeur, persecution) • Negative Symptoms (insufficient functioning) • avolition (inability to initiate/persist in activities) • alogia (absence of speech) • anhedonia (inability to experience pleasure) • affective flattening (flat emotional response) • Disorganized Symptoms • inappropriate affect (laughing/crying at the wrong times) • disorganized speech (illogical, rambling, tangential) • disorganized behavior (catatonia, agitation/immobility)
Schizophrenia Subtypes • Paranoid Type • hallucinations • delusions • Catatonic Type • unusual motor responses • remaining in a fixed position • excessive activity or rigidity • echoing words or movements of others • Disorganized Type • speech problems • behavior problems • flat or inappropriate affect
Schizophreni Genetic Risk by Relatedness • The Evidence: • Family History • Twin Studies • monozygotic (50%) • same handed (92%) • dizygotic (15%) • both are carriers • Adopted Children • more like bioparents • Single Gene? • Probably not
Brain Structure AbnormalitiesReduced Hippocampus and Amygdala Affected Normal Affected Normal
Brain Structure AbnormalitiesHippocampal Pyramidal Cell Disorganization
Brain Structure AbnormalitiesAtypical Frontal Lobe Functioning • Evidence: • smaller forebrain • smaller cerebral cortex • smaller dorsolateral prefrontal cortex • fewer cortical neurons • smaller cortical neurons • abnormal neuronal development • neurons remain in white matter • fail to arrange in neat order • abnormal CAMs • less metabolic activity • hypofrontality • failure to increase activity following task • abnormal EEGs
Neurobehavioral Hypothesis • Maternal/Fetal Evidence: • extensive maternal bleeding • prolonged labor • delivery complications • low birth weight • low head circumference • body length:body weight • multiparity • Anectodal Evidence • Dutch births during WWII • Season of birth effect • higher for winter pregnancies • parallel with virus exposure
Dopamine Hypothesis of Schizophrenia Abnormal levels of Dopamine lead to the schizophrenic symptoms • 1. Amphetamine Psychosis • Chronic users develop schizophrenic symptoms • paranoia, delusions of persecution, auditory hallucinations • Amphetamine exacerbates schizophrenic symptoms • Amphetamines promote the release of catelcholamines • particularly dopamine • 2. Antipsychotic Drugs • chlorapromazine is a dopamine antagonist and antipsychotic • block specifically D2 and D4 receptors in the limbic system • effectiveness is related to magnitude of blockade • 3. Parkinson’s Disease • some patients receiving L-dopa become psychotic • some schizophrenic patients on antipsychotics develop Parkinson’s symptoms