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Chapter 10

Ch. 10 - Introduction to Schizophrenia.docx

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Department
Psychology
Course
PSYC 208
Professor
Paul Wehr
Semester
Fall

Description
Schizophrenia 10/31/2012 10:38:00 AM Introduction to Schizophrenia  Schizophrenias are a heterogeneous collection of psychotic disorders (mind split from reality)  1 in 100 will develop schizophrenia  Not multiple personality disorder (DID)  Cognitive deficits o Thought o Perception: ability to perceive sensory input o Behavior o Emotion  Severe mental disorder o Dramatic reduction in fitness beginning during prime reproductive years o Strikes at the peak of reproductive years Negative Symptoms  Behavior deficits o Avolition: apathetic towards work, social, personal activities (e.g. grooming); often inactive o Alogia: poverty of speech or content o Anhedonia: inability to experience pleasure o Flat affect: no visible expression of internal emotional states  Affect: emotion  Doesn’t mean they’re not experiencing emotion  Refers to expression only, not experience  Kring & Neale: patients showed little facial expression while watching an emotional film, but reported similar feelings as non-patients o Inappropriate affect: wrong emotion o Asociality (social withdrawal): few friends and poor social skills o Impoverished motor activity Positive Symptoms  Behavioral excesses or peculiarities o Delusions: persistent and unrealistic false beliefs o Hallucinations: perceptions that occur in the absence of a physical stimulus, or that are distorted o Disorganized or hyperactive motor behavior o Disorganized or chaotic thought  Most patients exhibit both; differ in degree only o Positive > Negative: Better adjustment before onset and better response to non treatment Subtypes Defined by Positive Symptoms  Paranoid Type (common) o Delusions of persecution and grandeur  Theft of thoughts or broadcasting of thoughts  Thought control  Behavioral control o Auditory hallucinations  Own thoughts spoken by another voice  Voices arguing o Become suspicious of social network, institutions, unknown persons/entities  Disorganized Type o Severe deterioration of speech and behavior  Incoherent and fragmented speech (repeated reference to a theme)  Derailment (loose associations): difficulty staying on topic o Flat or inappropriate affect and social withdrawal Subtype Defined by Negative Symptoms  Catatonic Type (uncommon) o Mutism: absence or minimal speech o Stupor: slowed or lack of voluntary movement o Negativism: no response to instructions or does the opposite o Catalepsy: rigidity of limbs and bizarre posturing; “waxy flexibility” when limbs moved o Stereotyped behavior: persistent, repetitive purposeless movements o Mannerisms: conspicuous, exaggerated and distorted movement o Echolalia (imitates speech) and echopraxia (imitates movement) o Characterized by motor disturbances Other Subtypes  Undifferentiated Type (most common): Idiosyncratic mixture of symptoms  Residual Type: psychotic symptoms have subsided but persist in attenuated form  Schizophreniform Disorder: schizophrenic episode lasting longer than 1 month but less than 6 months  Good prognosis o Rapid onset vs. insidious onset o Confusion at height of episode o High social and occupational functioning prior to onset o Absence of flat affect (negative symptoms) Other Schizophrenias  Schizoaffective Disorder o Shizophrenic episode combined with Major Depression, Mania, or both; delusions or hallucinations occur in the absence of mood symptoms (2 weeks) o Continuum with mood disorder and psychotic disorders at anchors  Delusional Disorder o Non-bizarre delusions (e.g. being followed) o Hallucinations consistent with the delusion, but no other psychotic symptoms; high level of functioning o Specific types  Erotomanic Type: someone important in love with the individual  Grandiose Type: inflated worth  Jealous Type: unfaithful spouse  Persecutory Type: malevolent intentions of others  Somatic Type: physical defect or disease  Mixed Type  Unspecified Type o Also overlaps with OCD Epidemiology  Lifetime prevalence: <1% worldwide  Onset is typically in late adolescence or young adulthood o Some cases in childhood o Rare after age 40  Male to female ratio – 1.2:1.0  Attenuated psychotic symptoms and social withdrawal precede first episode by several years Genetic Risk Factors  Concordance rates o MZ twins: 48% o DZ twins: 17%  If both parents have schizophrenia: 46% chance for offspring  Polygentic disorder o Genes involved in regulation of dopamine and serotonin activity o Polymorphisms of neurotrophins (proteins) involved in synapse creation and pruning, and neuron development and survival o Cannabinoid receptor coding gene Environmental Risk Factors  Exposure to influenza and other viruses during second trimester (epidemic in Finland 1957)  Birth complications  Prenatal malnutrition (Nazi blockade of Netherlands 1944-45)  Urban environments  Immigration  Cannabis use  Physical and emotional abuse during childhood Brain Abnormalities  Structural abnormalities o Enlarged ventricles o Reduced gray matter (prefrontal and temporal lobes) o Deficits in executive functioning and social cognition  Neurotransmitter abnormalities o Increased dopamine production in the midbrain (positive symptoms) o Decreased dopamine activity in the prefrontal lobe (negative symptoms) o Other neurotransmitters involved  Problems with decision making, planning, and problem solving Course and Outcome  Single psychotic episode with remission and favorable outcome: 20-30%  Multiple episodes with (partial) remission in between: 30%  Chronic deteriorating course with increasing negative symptoms: 33%; require constant care  Relapse rate o Using medication: 20-30% o Stop using medication: 70-80% within 3-7 months Treatment  Institutionalization and behavior management prior to 1950s o Prisons and mental institutions o Psychosurgery and ECT  Antipsychotic Drugs (1950s) o Wouldn’t know that they had schizophrenia unless they told you, influence dopamine o Prevention of harmful behavior o Reduction in positive symptoms o Side effects: tardive dyskinesia, parkinsonism, dystonia, akathisia  Dyskinesia: involuntary motor movements  Parkinsonism: retarded motor movements, slow motor movements, decrease in dopamine  Dystonia: twist body awkwardly, and remain like that  Akathisia: can’t sit still, can’t relax, increased motor movements (motor restlessness)  Second Generation Antipsychotics o More people respond to these drugs o Reduction of negative symptoms o Higher response rate o Fewer side-effects o Lower suicide rate Neurodevelopmental Hypothesis  Disruptions to normal brain maturation during second trimester or at time of birth increase the risk for schizophrenia later in life:  Leads to subtle neurological damage as individual gets over o Abnormal neurogenesis  Parallels with autism “Two-hit” Hypothesis  Early neuronal disruption is follows by further disruptions to brain maturation and reorganization during adolescence o Positive social stressors (romantic relationship) o Negative social stressors (peer pressure) o Expressed emotion in the home (positive or negative)  Expressed emotion: degree to which relatives express negative emotions towards patient; overly critical/protective o Cannabis use  Critical stage in which development and reorganization showdown o Insufficient repair mechanisms and reduced plasticity  Second hit can lead to prodromal schizophrenia (e.g. delayed physical and intellectual development; social withdrawal) and predict first psychotic episode in early adulthood o Prodromal symptoms are not schizophrenic symptoms; do not indicate that schizophrenia is inevitable Evolutionary Synthesis  Paradox: genes related to the schizophrenias continue to persist despite devastating effect on fitness o Onset occurs during peak reproductive years o Reduction in reproductive success 30%-70%  Schizophrenias are a heterogeneous collection of disorders; single unifying explanation is unlikely  Variety of evolutionary hypotheses have been developed; many are unsatisfactory  Fitness reduced in males particularly Symptoms as Extreme Expressions of Adaptive Traits  Disrupted thought and paranoia reflect hyper-functioning “Theory of Mind” o Think that there’s something in other person’s mind that isn’t there o Inaccurate and they do it more often than other people  Tendency to over-infer mental states and inaccurate attributions of mental states o Interpret social cues as threat (e.g. paranoia) o Hyper-vigilant gaze monitoring o Over-attribution of malicious intentions by others (delusions of persecution) o Impaired ability to distinguish between self and other:  Thought insertions and behavioral control  Mistakes internal voice as belonging to someone else (auditory hallucinations)  Hyper-functioning of concerns for reproduction and survival expressed in delusions o Delusions of persecution reflect ancestral threats  Men more likely feel persecuted by groups of unknown males  CIA, the Masons…  Women more likely feel persecuted by individuals from personal environment  Scared of men they know… o Delusions related to mating effort:  Men more likely to have delusional jealousy; reflects concern over partner infidelity and abandonment  Women more likely to have delusional erotomania; reflects concern over partner investment and status; love objects are usually socially high-standing men; effort is expended to convince love object of their own mate value  Erotomania is NOT stalking; stalkers are typically male; more likely to use aggression, and don’t believe the victim is in love with them o Delusional content is consistent across cultures  Hyper-functioning fear response in catatonia  Catatonic stupor resembles primitive fear reaction o Immobility, heightened alertness, reduced vocalization, unfocused gaze, analgesia  Stay in awkward positions for hours at a time  Freezing: stopping, becoming alert, and vigilant (like animals) o Ferocious struggle to escape  Flight: rapid retreat from threat o Extreme hyperactivity before and after catatonic immobility; poorly coordinated assaultive behavior  Flight: attacking source of threat o Waxy-flexibility, imitation, obedience  Submission: yielding to member of own-species to prevent/stop attack o Report feelings of overwhelming anxiety (fear) o Benzodiazepines treat catatonia; dopamine worsens catatonia  Catatonia often observed in depression; submission and appeasement strategies Distribution of Risky Behavior Group Splitting Hypothesis  Group Selection Argument: when groups reach critical size of 40-60 individuals, group splits into two  Shizotypal Personality is a born leader o Delusions of grandeur; paranoia of outsiders o Charismatic leaders from history: rapidly shifting emotions, bizarre speech patterns, divine preoccupation o Social conditions: large groups outgrowing their resources leads to deprivation, mutual suspicion, hostility, and lack of cohesion o New group coalesces around schizotypal leader and believes themselves “chosen”; initiate hostility towards other groups o Leaders typically receive more/better mating opportunities o Genes associated with schizophrenia appeared before migration from Africa (similar rates worldwide)  Many charismatic leaders from history qualify for schizotypal personality disorder (Hitler, Joan of Arc, Charles Manson)  Group selection: in order for a new group to form, they must replace an existing group o Human habitats were traditional at carrying capacity o Intergroup hostility is a fact of life in hunter-gatherer societies o Group selection arguments are problematic because selection is stronger at the individual level o Shamans exist in all known societies Balanced Polymorphism  Genes have multiple effects and are expressed differently depending on what other genes are present/absent  Loss of fitness in schizophrenic individual is offset by fitness advantages in relatives o Superior social skill in relatives? No evidence. o Resistance to infectious disease in relatives (typical of balanced polymorphisms). Confirmed (once) o Reduced risk of cancer in relatives? o Creativity or enhanced theory of mind in relatives?  Superior academic success  Link between creativity/intelligence and schizophrenia  John Nash, Newton, Einstein’s son, Bertrand Russell  Assumes that schizophrenia is a homogeneous disorder, but clearly it is not  Suggests that genes leading to schizophrenia are adaptive in others Psychotic Disorders are Trade-offs of Language Acquisition  Language is lateralized such that speech comprehension and production are located in the left hemisphere whereas phonetic aspects of speech are located in right hemisphere (in right- handed individuals) o Explains handedness in humans absent in other primates  Schizophrenia reflects a failure to establish functional dominance in the right and left hemispheres o Schizophrenics exhibit reduced brain lateralization o Ambidextrous children more likely to have language disorders and to develop psychotic disorders o Men depend on greater lateralization: symptom severity is worse and onset is earlier o Could explain auditory hallucinations and disorganized thought  Doesn’t explain symptoms other than thought disorder and auditory hallucinations  Link between language ability and handedness still contentious  Doesn’t’ explain why genes leading to less lateralization persist in the population  Left handed individuals are less lateralized and also have increased risk of schizophrenia Maternal Imprinting Hypothesis  Over-expression of maternal genes lead to underdevelopment and “femaleness” of the brain  Does not explain the full spectrum of schizophrenia Developmental Disruption Hypothesis  Sexual Selection Fitness Indicator (SSFI): traits that signify high fitness (good genes or good condition)  Examples: peacock’s tail; bilateral symmetry  Attractive because development is easily disrupted by mutations or by environmental hazards (hone
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