Chapter 16 Schizophrenia and Affective Disorders


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Chapter 16 Schizophrenia and Affective Disorders

  1. 1. Chapter 16 Schizophrenia and Affective Disorders
  2. 2. <ul><li>Schizophrenia </li></ul><ul><ul><li>Description </li></ul></ul><ul><ul><li>Schizophrenia: </li></ul></ul><ul><ul><ul><li>A serious mental disorder characterized by: </li></ul></ul></ul><ul><ul><ul><ul><li>Disordered thoughts </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Delusions of persecution or grandeur </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Hallucinations (mostly auditory) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Behaviors (withdrawn or detached, odd movements)) </li></ul></ul></ul></ul>
  3. 3. <ul><li>Schizophrenia </li></ul><ul><ul><li>Description </li></ul></ul><ul><ul><li>Positive symptom: (known by their presence) </li></ul></ul><ul><ul><ul><li>delusions, hallucinations, abnormal movements, or thought disorders. </li></ul></ul></ul><ul><ul><li>Negative symptom: (characterized by absence) </li></ul></ul><ul><ul><ul><li>social withdrawal, lack of affect, and reduced motivation. </li></ul></ul></ul>
  4. 4. <ul><li>Schizophrenia </li></ul><ul><ul><li>Possible Causes: </li></ul></ul><ul><ul><ul><li>Heritability: In its simplest form, if schizophrenia was determined by a single dominant gene, about 75% of children from schizophrenic parents would get it. If it was recessive, about 50% would inherit the disorder. An incidence less than 50% suggests that the disease is determined by multiple genes and that only a susceptibility is passed on. </li></ul></ul></ul>
  5. 5. <ul><li>Schizophrenia </li></ul><ul><ul><li>Evidence for heritability </li></ul></ul><ul><ul><ul><li>Concordance rates: </li></ul></ul></ul><ul><ul><ul><ul><li>Most studies suggest between 25-40% in identical twins and about 5-20% in fraternal twins. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Clearly, the environment is an important contribution. </li></ul></ul></ul></ul>
  6. 6. <ul><li>Schizophrenia </li></ul><ul><ul><li>Biochemical Causes </li></ul></ul><ul><ul><ul><li>Dopamine Hypothesis: schizophrenia is caused by excessive dopamine activity in the mesolimbic system. </li></ul></ul></ul><ul><ul><ul><li>Supporting evidence: drug treatment, amphetamine psychosis, treatment for Parkinson’s disease </li></ul></ul></ul><ul><ul><ul><li>Additional evidence: increased DA activity, increased D3 & D4 receptors in mesolimbic system, </li></ul></ul></ul>
  7. 7. <ul><li>Schizophrenia </li></ul><ul><ul><li>Pharmacology of Schizophrenia </li></ul></ul><ul><ul><li>Chlorpromazine: A phenothiazine </li></ul></ul><ul><ul><ul><li>A “typical neuroleptic”; a nonspecific dopamine receptor blocker; first prescribed antischizophrenic drug. </li></ul></ul></ul><ul><ul><li>Clozapine: </li></ul></ul><ul><ul><ul><li>An “atypical neuroleptic”; an antipsychotic drug that blocks D 4 receptors in the nucleus accumbens. Little effect on D2 receptors </li></ul></ul></ul>
  8. 8. Copyright © 2004 Allyn and Bacon
  9. 9. Copyright © 2004 Allyn and Bacon
  10. 10. <ul><li>Schizophrenia </li></ul><ul><ul><li>Consequences of Long-Term Drug Treatment of Schizophrenia </li></ul></ul><ul><ul><li>Tardive dyskinesia: </li></ul></ul><ul><ul><ul><li>A movement disorder that can occur after prolonged treatment with antipsychotic medication, characterized by involuntary movements of the face and neck. </li></ul></ul></ul><ul><ul><li>Supersensitivity: </li></ul></ul><ul><ul><ul><li>The increased sensitivity of neurotransmitter receptors; caused by damage to the afferent axons or long-term blockage of neurotransmitter release. </li></ul></ul></ul>
  11. 11. <ul><li>Schizophrenia </li></ul><ul><ul><li>Evidence for neurological abnormalities Negative symptoms </li></ul></ul><ul><ul><li>Schizophrenics with negative symptoms have similar symptoms as those with fromtal lobe damage. </li></ul></ul><ul><ul><ul><li>Frontal lobe size </li></ul></ul></ul><ul><ul><ul><li>Ventrical size </li></ul></ul></ul><ul><ul><ul><li>Cerebral gray matter decreases </li></ul></ul></ul>
  12. 12. Copyright © 2004 Allyn and Bacon
  13. 13. Copyright © 2004 Allyn and Bacon
  14. 14. <ul><li>Schizophrenia </li></ul><ul><ul><li>Possible Causes of the Brain Abnormalities </li></ul></ul><ul><ul><li>Epidemiology: </li></ul></ul><ul><ul><ul><li>The study of the distribution and causes of diseases in populations. </li></ul></ul></ul><ul><ul><ul><li>Research suggest several environmental factors: </li></ul></ul></ul><ul><ul><ul><ul><li>-Season of birth: greatest during winter months </li></ul></ul></ul></ul><ul><ul><ul><ul><li>-Viral epidemics: associated with viral diseases </li></ul></ul></ul></ul><ul><ul><ul><ul><li>-Latitude: increased incidence further from equator </li></ul></ul></ul></ul><ul><ul><ul><ul><li>-Prenatal malnutrition: ? </li></ul></ul></ul></ul><ul><ul><ul><ul><li>-Rh incompatibility: ? </li></ul></ul></ul></ul><ul><ul><ul><ul><li>-Maternal stress: ? </li></ul></ul></ul></ul>
  15. 15. Copyright © 2004 Allyn and Bacon
  16. 16. Copyright © 2004 Allyn and Bacon
  17. 18. Copyright © 2004 Allyn and Bacon
  18. 19. Copyright © 2004 Allyn and Bacon
  19. 20. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Description </li></ul></ul><ul><ul><li>Major affective disorders: </li></ul></ul><ul><ul><ul><li>A serious mood disorder; includes major depressive disorder and bipolar disorder. </li></ul></ul></ul><ul><ul><ul><li>May effect as many as 5% of US population in a given year. Perhaps as many as 25% over lifetime. </li></ul></ul></ul>
  20. 21. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Description </li></ul></ul><ul><ul><li>Major depressive disorder: </li></ul></ul><ul><ul><ul><li>A serious mood disorder that consists of unremitting depression or periods of depression that do not alternate with periods of mania. </li></ul></ul></ul><ul><ul><li>Bipolar disorder: </li></ul></ul><ul><ul><ul><li>A serious mood disorder characterized by cyclical periods of mania and depression. </li></ul></ul></ul>
  21. 22. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Causes of Depression </li></ul></ul><ul><ul><li>Genetic contributions: </li></ul></ul><ul><ul><ul><li>Bipolar disorder may be caused by a single dominant gene. Location still not confirmed, but heritability studies reveal strong link. </li></ul></ul></ul><ul><ul><li>Major depressive disorder: </li></ul></ul><ul><ul><ul><li>Less likely caused by single gene than bipolar disorder. </li></ul></ul></ul><ul><ul><ul><li>Amine hypothesis: deficiencies in activity of one or several amine neurotransmitter systems (NE, SE) </li></ul></ul></ul>
  22. 23. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Drug Treatment for Depression </li></ul></ul><ul><ul><li>Tricyclic antidepressants: </li></ul></ul><ul><ul><ul><li>A class of drugs used to treat depression; inhibits the reuptake of norepinephrine and serotonin; named for the specific molecular structure. Amitriptyline (Elavil) </li></ul></ul></ul><ul><ul><li>Monoamine oxidase inhibitors (MAOIs): </li></ul></ul><ul><ul><ul><li>Prevent degradation of NT in synapse. </li></ul></ul></ul><ul><ul><ul><li>phenelzine (Nardil) </li></ul></ul></ul><ul><ul><li>Serotonin specific reuptake inhibitor (SSRI): </li></ul></ul><ul><ul><ul><li>A drug that inhibits the reuptake of serotonin without affecting the reuptake of other neurotransmitters. </li></ul></ul></ul><ul><ul><ul><li>fluoxetine (Prozac) </li></ul></ul></ul>
  23. 24. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Physiological Treatments </li></ul></ul><ul><ul><li>Lithium </li></ul></ul><ul><ul><ul><li>A chemical element; lithium carbonate is used to treat bipolar disorder </li></ul></ul></ul><ul><ul><li>Carbamazepine: </li></ul></ul><ul><ul><ul><li>An anticonvulsive drug (trade name: Tegretol) that is used to treat seizures originating from a focus, also used to treat mania in bipolar disorder. </li></ul></ul></ul>
  24. 25. Copyright © 2004 Allyn and Bacon
  25. 26. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Physiological Treatments Electroconvulsive therapy (ECT): </li></ul></ul><ul><ul><ul><li>A brief electrical shock that induces a seizure; used therapeutically to alleviate severe depression when medication is not effective. </li></ul></ul></ul><ul><ul><ul><li>Transcranial Magnetic Stimulation (TMS): </li></ul></ul></ul><ul><ul><ul><li>Magnetic field causes a weak electrical field and electrical current within the brain. Has been useful in some cases of depression. </li></ul></ul></ul>
  26. 27. Copyright © 2004 Allyn and Bacon
  27. 28. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Evidence of Brain Abnormalities </li></ul></ul><ul><ul><li>Brain abnormalities: </li></ul></ul><ul><ul><ul><li>Research suggests abnormalities in the prefrontal cortex, basal ganglia, hippocampus, thalamus, cerebellum, and temporal lobes. </li></ul></ul></ul><ul><ul><ul><li>Some evidence suggests increased size of the cerebral ventricles may suggest the loss of neural tissue. </li></ul></ul></ul>
  28. 29. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Evidence of Brain Abnormalities </li></ul></ul><ul><ul><li>Silent cerebral infarction (SCI): </li></ul></ul><ul><ul><ul><li>A small cerebrovascular accident (stroke) that causes minor brain damage without producing obvious neurological symptoms. </li></ul></ul></ul>
  29. 30. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Role of Circadian Rhythms </li></ul></ul><ul><ul><li>REM Sleep Deprivation: </li></ul></ul><ul><ul><ul><li>Selective deprivation of REM sleep through EEG monitoring, is one of the most effective antidepressant treatments; suggests a close relationship between REM sleep and mood. </li></ul></ul></ul><ul><ul><ul><li>Antidepressant effects require several weeks of deprivation. </li></ul></ul></ul>
  30. 31. Copyright © 2004 Allyn and Bacon
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  33. 34. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Role of Circadian Rhythms </li></ul></ul><ul><ul><li>Total Sleep Deprivation: </li></ul></ul><ul><ul><ul><li>Total sleep deprivation has antidepressant effect that are immediate; however, the procedure is not very practical. </li></ul></ul></ul><ul><ul><ul><li>Some individuals do not respond to total or selective sleep deprivation. </li></ul></ul></ul>
  34. 35. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Role of Zeitgebers </li></ul></ul><ul><ul><li>Seasonal affective disorder (SAD): </li></ul></ul><ul><ul><ul><li>A mood disorder characterized by depression, lethargy, sleep disturbances, and craving for carbohydrates during the winter months. </li></ul></ul></ul><ul><ul><li>Summer depression: </li></ul></ul><ul><ul><ul><li>A mood disorder characterized by depression, sleep disturbances, and loss of appetite. </li></ul></ul></ul>
  35. 36. <ul><li>Major Affective Disorders </li></ul><ul><ul><li>Role of Zeitgebers </li></ul></ul><ul><ul><li>Phototherapy: </li></ul></ul><ul><ul><ul><li>Treatment of seasonal affective disorder by daily exposure to bright light. </li></ul></ul></ul>