Presentation Transcript

1. COGNITIVE SCIENCE 17 The Brain Gone Bad Part 1 Jaime A. Pineda, Ph.D. Meshberger, JAMA 264:1837-1841

2. Schizophrenia is a PSYCHOTIC DISORDERA severe mental disorder in which thinking and emotion are so impaired that the individual is seriously out of contact with reality.

3. Progression of Schizophrenia Louis Wain

4. Early onset schizophrenia: Wave of gray matter loss - begins in parietal cortex and spreads forward

5. Schizophrenia Refers to a group of disorders There is not one essential symptom that must be present for a diagnosis. Instead, patients experience different combinations of the main symptoms of schizophrenia. It is NOT split or multiple personality disorder.

6. Two Categories of Symptoms in Schizophrenia • Positive symptoms • Negative symptoms

7. Positive Symptoms • Distortions or excesses of normal functioning • delusions, • hallucinations, • disorganized speech, • thought disturbances, • motor disturbances • Positive symptoms are generally more responsive to treatment than negative symptoms

8. Delusions • False beliefs that are firmly and consistently held despite disconfirming evidence or logic • Individuals with mania or delusional depression may also experience delusions. • However, the delusions of patients with schizophrenia are often more bizarre (highly implausible).

9. Types of Delusions • Delusions of Grandeur • Belief that one is a famous or powerful person from the past or present • Delusions of Control • Belief that some external force is trying to take control of one’s thoughts (thought insertion), body, or behavior

10. Examples of Delusions of ControlBelieving that thoughts that are not your own have been placed in your mind by an external sourceA 29-year-old housewife said, “I look out of the window and I think the garden looks nice and the grass looks cool, but the thoughts of Eamonn Andrews come into my mind. There are no other thoughts there, only his… He treats my mind like a screen and flashes his thoughts on it like you flash a picture.”

11. Examples of Delusions of ControlBelieving that your behavior is controlled by an external forceA 29-year-old shorthand typist described her (simplest) actions as follows: “When I reach my hand for the comb it is my hand and arm which move, and my fingers pick up the pen, but I don’t control them… I sit there watching them move, and they are quite independent, what they do is nothing to do with me… I am just a puppet who is manipulated by cosmic strings. When the strings are pulled my body moves and I cannot prevent it.”

12. Types of Delusions • Thought Broadcasting • Belief that one’s thoughts are being broadcast or transmitted to others • Thought Withdrawal • Belief that one’s thoughts are being removed from one’s mind

13. Types of Delusions • Delusions of Reference • Belief that all happenings revolve around oneself, and/or one is always the center of attention • Delusions of Persecution • Belief that one is the target of others’ mistreatment, evil plots, and/or murderous intent

14. Hallucinations • Sensory experiences in the absence of any stimulation from the environment • Any sensory modality may be involved • auditory (hearing); • visual (seeing); • olfactory (smelling); • tactile (feeling); • gustatory (tasting) • Auditory hallucinations are most common

15. Common Auditory Hallucinations in Schizophrenia • Hearing own thoughts spoken by another voice • Hearing voices that are arguing • Hearing voices commenting on one’s own behavior

16. Disorganized Speech / Thought Disturbances • Problems in organizing ideas and speaking so that a listener can understand • Loose Associations (cognitive slippage) • continual shifting from topic to topic without any apparent or logical connection between thoughts • Neologisms • new, seemingly meaningless words that are formed by combining words

17. Disorganized Motor Disturbances • Extreme activity levels (unusually high or low), peculiar body movements or postures (e.g., catatonic schizophrenia), strange gestures and grimaces

18. Negative Symptoms • Behavioral deficits that endure beyond an acute episode of schizophrenia • More negative symptoms are associated with a poorer prognosis • Some negative symptoms might be secondary to medications and/or institutionalization

19. Types of Negative Symptoms • Anhedonia • inability to feel pleasure; lack of interest or enjoyment in activities or relationships • Avolition • inability or lack of energy to engage in routine (e.g., personal hygiene) and/or goal-directed (e.g., work, school) activities

20. Types of Negative Symptoms • Alogia • lack of meaningful speech, which may take several forms, including poverty of speech (reduced amount of speech) or poverty of content of speech (little information is conveyed; vague, repetitive) • Asociality • impairments in social relationships; few friends, poor social skills, little interest in being with other people

21. Types of Negative Symptoms • Flat Affect • No stimulus can elicit an emotional response • Patient may stare vacantly, with lifeless eyes and expressionless face. • Voice may be toneless. • Flat affect refers only to outward expression, not necessarily internal experience.

22. Genetic Studies • Twin • Blood relatives • Adoption • High-risk populations (e.g., children of schizophrenic parents) • Calcineurin and short-term memory (Tonegawa, 2003)

25. Biological Finding • The Dopamine Hypothesis • Disturbed functioning in dopamine system (i.e., excess dopamine activity at certain synaptic sites) • Supportive evidence: • Phenothiazines reduce dopamine activity and psychotic symptoms are reduced; • L-Dopa and amphetamines increase dopamine activity and can produce psychotic symptoms

27. Problems • A large minority of people with schizophrenia are not responsive to antipsychotic medications affecting dopamine. • Other effective medications (Clozapine) work primarily on serotonin, rather than dopamine, system. • Antipsychotic drugs block dopamine receptors quickly, but relief from symptoms is not seen for weeks.

28. Biological Finding • Enlarged ventricles (i.e., spaces) in the brain and/or decreased volume in frontal & temporal lobes • Indicates deterioration or atrophy of brain tissue • Supportive evidence: CT scan & MRI studies

29. Problems • Differences are relatively small compared with control groups, and many schizophrenic patients fall within normal range. • Reported in only 6 to 40 percent of schizophrenic patients in a variety of studies. • Also reported in some patients with mood disorders.

30. Biological Finding • Low relative glucose metabolism in frontal areas

31. Problems • Participants are generally chronic patients on heavy neuroleptic medications. • Some evidence indicates that antipsychotic medications influence cerebral blood flow even in patients who are currently medication free.

32. Biological Finding • Cognitive dysfunctions (visual processing, attention problems, recall memory problems)

33. Problems • Some members of control groups also have such dysfunctions. • May be a result of medication, hospitalization, or other such variables. • Validity of measures is questionable.

34. Environmental Factors • Family Characteristics • Social Class

35. Social Class and Schizophrenia • Schizophrenia is most common at lower socioeconomic status (SES) levels • Breeder Hypothesis • stressors associated with low SES increase the likelihood that schizophrenia will develop • Downward Drift Theory • individuals with schizophrenia drift into low SES areas because they cannot function in other environments