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CHAPTER TWO

CHAPTER TWO. Causes of Abnormal Behavior: A Systems Approach. Causes of Abnormal Behavior. What are paradigms? 4 basic psychological paradigms Behavior genetics Systems theory. What is a Paradigm?. A set of shared assumptions about: the substance of a theory

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CHAPTER TWO

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  1. CHAPTER TWO Causes of Abnormal Behavior: A Systems Approach

  2. Causes of Abnormal Behavior • What are paradigms? • 4 basic psychological paradigms • Behavior genetics • Systems theory

  3. What is a Paradigm? A set of sharedassumptions about: • the substance of a theory • how scientists should collect data and test theoretical propositions.

  4. Causes of Abnormal Behavior • What are paradigms? • 4 basic psychological paradigms • Behavior genetics • Systems theory

  5. 4 Basic Psychological Paradigms • Psychodynamic • Cognitive-Behavioral • Humanistic • Biological

  6. Which paradigm is correct?The blind men and the elephant

  7. Which paradigm is correct? Two answers: • Individually, all of them • Some or all of them together • This approach is a Systems theory or biopsychosocial approach

  8. Causes of Abnormal Behavior • What are paradigms? • 4 basic psychological paradigms • Systems theory • Behavior genetics

  9. Systems Theory: Outline • Definition • Causality • Levels of Analysis

  10. Systems Theory: Definition • No one paradigm offers the “right” approach. Systems theory integrates evidence from the biological, psychological and social domains. • The centerpiece of systems theory is: Holism: whole=more than the sum of parts e.g. playing in a sports team (basketball, volleyball) The opposite of holism is: Reductionism: whole = sum of its parts. e.g. playing in a sports team (gymnastics, wrestling)

  11. Systems Theory: Causality • Diathesis-Stress Model • Diathesis: existing vulnerability that precedes stressor • Stress: any event that triggers the onset of disturbance • A diathesis may or may not be biological, and a stressor may or may not be environmental.

  12. Systems Theory: Causality Equifinality: different causes for same disorder Death of parent Loss of job Change in brain chemistry Depression Depression Depression

  13. Systems Theory: Causality Multifinality: same causal factor but different outcomes Earthquake Phobia PTSD Depression

  14. Systems Theory: Causality Reciprocal causality: causality is bidirectional. Parent’s behavior Child’s behavior

  15. Systems Theory: Levels of Analysis • Systems theory integrates evidence from biological, psychological and social domains of behavior (not additive) • Different paradigms operate at different levels of analysis when explaining human behavior: e.g., neuron, individual, couple, family, community, culture.

  16. Multidimensional Model • 50% of psychology due to biological factors, 50% due to social factors?? Misleading… • Because interactions between factors are more important

  17. Causes of Abnormal Behavior • What are paradigms? • 4 basic psychological paradigms • Systems theory • Behavior genetics

  18. Biological Paradigm: Behavior Genetics • Behavior genetics • the study of genetic contributions to the development of normal and abnormal behaviors • Genotype • total genetic make-up (genetic profile)

  19. Biological Paradigm: Behavior Genetics • Phenotype • observable expression/characteristics of genotype (such as weight and eye color) • Genotype is fixed at birth, but phenotype is a result of genotype and experiences.

  20. Genotype vs. Phenotype

  21. Biological Paradigm: Behavior Genetics • There are three different approaches to studying behavior genetics. • Family incidence studies • Twin studies • Adoption studies

  22. Biological Paradigm: Behavior Genetics Family Incidence Studies: Do disorders run in families? • Researchers identify the index person in a family or a proband • Then examine the proportion of family members that suffer from different disorders relative to this person (the proband)

  23. Biological Paradigm: Behavior Genetics Proband %family MDD %family Schz. MDD 30 0.5 Schizophrenia 10 10 No diagnosis 10 0.5 Hypothetical Data Set *Are members of my family at risk for having a disorder given that I have the disorder?

  24. Biological Paradigm: Behavior Genetics Proband %family MDD %family Schz. MDD 30 0.5 Schizophrenia 10 10 No diagnosis 10 0.5 Hypothetical Data Set

  25. Biological Paradigm: Behavior Genetics Proband %family MDD %family Schz. MDD 30 0.5 Schizophrenia 10 10 No diagnosis 10 0.5 Hypothetical Data Set

  26. Biological Paradigm: Behavior Genetics Proband %family MDD %family Schz. MDD 30 0.5 Schizophrenia 10 10 No diagnosis 10 0.5 Hypothetical Data Set

  27. Biological Paradigm: Behavior Genetics Proband %family MDD %family Schz. MDD 30 0.5 Schizophrenia 10 10 No diagnosis 10 0.5 Hypothetical Data Set

  28. Twin Studies: Logic Twin studies • Concordance, simply means “agreement” • Depressed Twin A = Depressed Twin B • Example: in a study of 100 Twins, if 60% of all the twins both have depression, then the concordance rate is 60% • MZ twins have 100% genetic overlap. • On average, DZ twins have 50% genetic overlap (like typical siblings)

  29. Twin Studies: Shortcoming • Assumes that pairs of MZ twins are not treated any more alike than are pairs of DZ twins • But MZ twins may be treated more alike because they look alike…

  30. Twin Studies: Twins Raised Apart (MZ twins) • To account for the fact that MZ twins may be treated more similarly than DZ • Different adoptive families (= different environment or different treatment) • Differences in concordance rates cannot be attributed to MZ twins having a more similar environment than DZ • Can’t assume similar treatment of MZ twins, so if differences are found they may be attributed to environmental factors…

  31. Behavior Genetics: Adoption Studies • Compare adopted children with and without family histories of a disorder • Compareconcordance rates with biological and adoptive parents to see which is higher • Genetic and environmental factors

  32. Adoption Study: Disorder X Proband % Adopted-Away children (Biological Parents) with Disorder WithDisorder X 20 WithoutDisorder X 10

  33. Adoption Study: Disorder X Proband % Adopted-Away children (Biological Parents) with Disorder WithDisorder X 20 WithoutDisorder X 10 * Children of Bio Parents with Disorder X are at a higher risk, so there is a Genetic Influence

  34. Adoption Study: Disorder Y Proband % Adopted-Away children (Biological Parents) with Disorder WithDisorder Y 10 WithoutDisorder Y 10

  35. Adoption Study: Disorder X Proband % Adopted-Away children (Biological Parents) with Disorder WithDisorder Y 10 WithoutDisorder Y 10 * Children of Bio Parents with Disorder Y are NOT at a higher risk, so there’s NO Genetic Influence

  36. Adoption Study: Disorder X % biological % adoptive Proband parents with parents with Disorder X Disorder X Adoptees with 20 10 Disorder X Adoptees without 10 10 Disorder X

  37. Adoption Study: Disorder X % biological % adoptive Proband parents with parents with Disorder X Disorder X Adoptees with 20 10 Disorder X Adoptees without 10 10 Disorder X * Bio Parents of children with Disorder X are at a higher risk compared to Adoptive Parents, so there is a Genetic Influence

  38. Adoption Study: Disorder Y % biological % adoptive Proband parents with parents with Disorder Y Disorder Y Adoptees with 10 10 Disorder Y Adoptees without 10 10 Disorder Y

  39. Adoption Study: Disorder Y % biological % adoptive Proband parents with parents with Disorder Y Disorder Y Adoptees with 10 10 Disorder Y Adoptees without 10 10 Disorder Y * Bio Parents of children with Disorder Y are NOT at a higher risk compared to Adoptive Parents, so there’s NO Genetic Influence

  40. Adoption Study: Disorder Z % biological % adoptive Proband parents with parents with Disorder Z Disorder Z Adoptees with 20 10 Disorder Z Adoptees without 20 10 Disorder Z

  41. Adoption Study: Disorder Z % biological % adoptive Proband parents with parents with Disorder Z Disorder Z Adoptees with 20 10 Disorder Z Adoptees without 20 10 Disorder Z * Bio Parents of children with Disorder Z are NOT at a higher risk compared to Bio Parents of children without Disorder Z, so there’s NO Genetic Influence

  42. Biological Paradigm: Behavior Genetics • Genes not sufficient to account for development of any psychological disorder. We need to study environmental factors • Gene-environment interactions: Reciprocal gene-environment model • Genes might influence the environment that people seek out. Environmental factors may bring out a genetic predisposition. The two are not independent.

  43. Misinterpretation of Behavior Genetics INCORRECT ASSUMPTIONS • If there is a genetic influence, a disorder is inevitable • If a behavior or characteristic is genetically influenced, it cannot be changed • If there is a genetic influence, a gene must be directly responsible for the behavior • i.e., environmental factors are often necessary to trigger the expression of genes • e.g., some people have genetic predisposition to alcohol, but they are still able to change • polygenetic + environmental stress

  44. Biological Perspective • Biology can be influenced by psychology! • Biological causes do not necessarily require biological treatment • Today most psychologists view disorders as being caused by multiple factors.

  45. Optional Slides

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