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Chapter 2

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Western University
Psychology 2030A/B
David Vollick

Abnormal  Psychology  Chapter  2:   An  Integrative  Approach  to  Psychopathology     Introduction   • Multidimensional  integrative  approach  has  a  biological  dimension  (genetics),   psychological  dimension  (behavioural  and  cognitive  processes),  emotional   influences,  and  social  and  interpersonal  influences  and  developmental   influences     One-­‐Dimensional  or  Multidimensional  Models   • A  linear  or  one-­‐dimensional  model,  which  attempts  to  trace  the  origins  of   behaviour  to  a  single  cause   • This  perspective  on  causality  is  systemic  which  implies  that  any  particular   influence  contributing  to  psychopathology  cannot  be  considered  out  of   context   • Context  is  the  biology,  cognitive,  and  emotional,  social,  and  cultural   environment  any  component  affects  the  other  components.  This  is  the   multimodal  model   • Baroreflex  increases  or  decreases  blood  pressure  in  an  effort  to  maintain   stable  blood  pressure  in  the  body  (emotional  influences)   • Rejection  can  make  psychological  disorders  worse  than  they  otherwise   would  be   • Being  supportive  when  somebody  experiences  symptoms  may  actually   increase  the  frequency  and  intensity  of  the  reaction   • Developmental  critical  period  when  we  are  more  or  less  reactive  to  a  given   situation  or  influence  than  at  other  times   • Applied  muscle  tension  reduces  vasovagal  reactions  by  maintaining  blood   pressure     Genetic  Contributions  to  Psychopathology   • Genes  are  very  long  molecules  of  DNA  at  various  location  on  chromosomes   within  the  nucleus   • To  some  extent  our  weight  and  even  our  height  are  affected  by  nutritional,   social,  and  cultural  factors   • Genes  seldom  determine  our  physical  development  in  any  absolute  way.   They  do  provide  some  boundaries  to  our  development.     The  Nature  of  Genes   • Humans  have  46  chromosomes  (23  pairs)   • Abnormalities  in  the  sex  chromosomal  pair  can  cause  ambiguous  sexual   characteristics   • The  ordering  of  these  base  pairs  determine  how  the  body  develops  and   works   • Much  of  our  development  and  behaviour,  personality,  and  even  IQ  is   probably  polygenic,  influenced  by  many  genes,  each  contributing  only  a  tiny   effect   • Look  for  patterns  of  influence  across  these  genes,  using  procedures  called   quantitative  genetics   • Sum  up  all  the  tiny  effects  across  many  genes  without  necessarily  telling  us   which  genes  are  responsible  for  which  effects     New  Developments  in  The  Study  of  Genes  and  Behaviour   • Half  our  enduring  personality  traits  and  cognitive  abilities  are  due  to  our   genes   • For  psychological  disorders,  the  evidence  that  genetic  factors  contribute  to   all  disorders   • People  with  severe  mental  retardations  have  identifiable  genetic  disorders   involving  a  single  gene  (fragile  X  syndrome  –  mostly  in  males)   • Specific  genes  may  ultimately  be  found  to  be  associated  with  certain   psychological  disorders   • Evidence  suggests  psychological  disorders  come  from  many  genes,  each   having  a  relatively  small  effect   • Genetic  contributions  cannot  be  studied  in  the  absence  of  interaction  with   events  in  the  environment  that  trigger  genetic  vulnerability  or  “turn  on”   specific  genes       The  Interaction  of  Genetic  and  Environmental  Effects   • Kandel  believed  that  the  process  of  learning  affects  more  than  behaviour   • He  suggest  that  genetic  structure  of  cells  may  actually  change  as  a  result  of   learning   • A  competing  idea  is  that  the  brain  and  its  functions  are  plastic,  subject  to   continual  change  in  response  to  the  environment   • There  are  two  models:  diathesis  stress  model  and  reciprocal  gene-­‐ environment   • Diathesis  Stress  Model:  individuals  inherit  tendencies  to  express  certain   traits  or  behaviours,  which  may  then  be  activated  under  conditions  of  stress   • Each  inherited  tendency  is  a  diathesis,  a  condition  that  makes  a  person   susceptible  to  developing  a  disorder.  This  tendency  is  called  vulnerability.   • Diathesis  is  genetically  based  and  the  stress  is  environmental,  but  they   interact  to  produce  a  disorder   • Serotonin  implicated  in  depression     • Caspi  determine  that  people  with  two  long  alleles  cope  better  with  stress   than  those  with  to  short  alleles   • Evidence  indicates  that  genetic  endowment  may  actually  increase  the   probability  that  an  individual  will  experience  stressful  life  events  (Reciprocal   Gene-­‐Environment  Model)   • Jang  determined  that  genes  influence  inheirited  personality  traits  such  as   impulsiveness  that  cause  people  to  enter  dangerous  situations  in  whih  such   types  of  traumas  are  most  likely  to  occur         Nongenomic  “Inheritance”  of  Behaviour   • Recent  reports  suggest  studies  overemphasized  the  extent  of  genetic   influence  on  our  personalities,  our  temperaments,  and  their  contribution  to   the  development  of  psychological  disorders   • Crabbe,  Wahlsten,  and  Dudek  experiment  concluded  “genetic  influences  are   often  a  lot  less  powerful  than  is  commonly  believed.  The  environment  can   still  mold  and  hold  its  own  in  the  biological  interactions  that  shape  who  we   are   • Meaney  demonstrated  that  maternal  behaviour  affected  how  the  young  rats   tolerated  stress   • Findings  suggest  that  individual  differences  in  the  expression  of  genes  in   brain  regions  that  regulate  stress  reactivity  can  be  transmitted  from  one   generation  to  the  next  through  behaviours   • Results  suggest  that  the  mechanism  for  this  pattern  of  inheritance  involved   differences  in  maternal  care   • Suomi  results  showed  that  environmental  effects  of  early  parenting  seem  to   override  any  genetic  contributions  to  be  anxious,  emotional,  or  reactive  to   stress   • This  influences  and  even  reverses  the  genetic  contribution  to  the  expression   of  personality  traits  or  temperaments   • A  specific  genetic  predisposition  may  never  express  itself  in  behaviour  unless   the  individual  is  exposed  to  a  certain  kind  of  environment     • Conversely,  a  certain  kind  of  environment  may  have  little  effect  on  a  child’s   development,  unless  that  child  carries  a  particular  genetic  endowment       • Strongest  evidence  exists  for  the  effects  of  early  parenting  influences  and   other  early  experiences   • Neither  nature  nor  nurture  alone  influences  the  development  of  our   behaviour  and  personalities,  but  a  complex  interaction  of  the  two     Neuroscience  And  Its  Contributions  to  Psychopathology   • Neuroscience  is  an  overview  of  the  nervous  system   • The  human  nervous  system  includes  the  central  nervous  system  (brain  and   spinal  cord)  and  the  peripheral  nervous  system,  which  consists  of  the   somatic  nervous  system  and  the  automatic  nervous  system     The  Central  Nervous  System   • CNS  processes  all  information  received  from  our  sense  organs  and  reacts  as   necessary   • The  spinal  cord  facilitates  the  sending  of  messages  to  and  from  the  brain   • Neurons  control  our  every  thought  and  action  and  transmit  information   throughout  the  nervous  system   • Neurons  contain  a  central  body  with  two  kinds  of  branches   o The  dendrite,  which  consist  of  numerous  receptors  that  receive   messages  in  the  form  of  chemical  impulses  from  other  nerve  cell,   which  are  converted  into  electrical  impulses   o The  axon,  which  transmits  these  impulses  to  other  neurons   • Nerve  cells  are  connected   • The  space  between  the  axon  of  one  neuron  and  the  dendrite  of  another  is   called  the  synaptic  cleft   • Chemicals  are  released  from  the  axon  of  one  nerve  cell  and  transmit  the   impulse  to  the  receptors  of  another  nerve  cell  called  the  neurotransmitters   • Major  neurotransmitters  are:  norepinephrine,  serotonin,  dopamine,  and   GABA   • Excesses  or  insufficiencies  of  some  neurotransmitters  are  associated  with   different  groups  of  psychological  disorders   • Figure  2.4   • Figure  2.5     The  Structure  of  The  Brain   • View  the  brain  in  two  parts:  the  brain  stem  and  the  forebrain   • The  brain  stem  is  the  lower  part  of  the  brain  associated  with  essential   automatic  functions   • The  lowest  part  of  the  brain  is  the  hindbrain  and  contains  the  medulla,  the   pons,  and  the  cerebellum.  It  regulated  many  automatic  activities.   • The  midbrain  coordinated  movement  with  sensory  input  and  contains  parts   of  the  reticular  activating  system  (RAS)   • The  thalamus  and  the  hypothalamus  involved  with  regulating  behaviour  and   emotion   • At  the  base  of  the  forebrain  is  the  limbic  system  which  includes  the   hippocampus,  cingulated  gyrus,  septum,  amyglada,  basal  ganglia,  caudate   nucleus,  and  cerebral  cortex   • The  cerebral  cortex  is  divided  into  two  hemispheres:  the  left,  responsible  for   verbal  and  other  cognitive  activities,  and  the  right,  for  creating  images   • PP.  42-­‐43     The  Peripheral  Nervous  System     • The  peripheral  nervous  system  has  two  major  components:  the  somatic  and   the  automatic  nervous  system   • The  somatic  nervous  system  controls  the  muscles   • The  automatic  nervous  system  (ANS)  includes  the  sympathetic  (SNS)  and   parasympathetic  nervous  system   • The  ANS  regulates  the  cardiovascular  system  and  the  endocrine  system   • The  endocrine  system  produces  hormones,  and  releases  it  directly  into  the   bloodstream   • The  SNS  is  primarily  responsible  fro  mobilizing  the  body  during  times  of   stress  and  danger   • The  parasympathetic  system  is  to  balance  the  sympathetic  system   • The  hypothalamus  connects  to  the  pituitary  gland,  which  stimulates  the   cortical  part  of  the  adrenal  glands   • Surges  of  epinephrine  energize  us   • The  adrenal  glands  produce  the  stress  hormones  cortical   • The  hypothalamic  pituitary  adrenalcortical  axis  or  HPA  axis  has  been   implicated  in  several  psychological  disorders     Neurotransmitters   • Neurons  that  are  sensitive  to  one  type  of  neurotransmitter  cluster  together   and  form  paths  from  one  part  of  the  brain  to  the  other   • Thousands  of  brain  circuits   • Drug  therapies  work  by  either  increasing  or  decreasing  the  flow  of  specific   neurotransmitters   • Other  drugs  do  not  affect  neurotransmitters  directly  but  prevent  the   chemical  from  reaching  he  next  neuron  by  closing  down  the  receptors  in  that   neuron   • After  a  neurotransmitter  is  released  it  is  quickly  drawn  back  from  the   synaptic  cleft  into  the  same  neuron,  this  is  called  reuptake   • Some  drugs  work  by  blocking  the  reuptake  process  causing  continued   stimulation  along  the  brain  circuit   • Effects  of  neurotransmitter  activity  are  more  general  and  less  specific.  They   often  seem  to  be  related  to  the  way  we  process  information   • Changes  in  neurotransmitter  activity  may  make  people  more  or  less  likely  to   exhibit  certain  kinds  of  behaviour  in  certain  stimulus  without  causing  the   behaviours  directly   • Research  on  neurotransmitter  function  focuses  primarily  on  what  happened   when  activity  levels  change   • Agonists  that  effectively  increase  the  activity  of  a  neurotransmitter  by   mimicking  its  effects   • Antagonists  decrease  or  block  a  neurotransmitter     • Inverse  agonists  produce  effects  opposite  to  those  produced  by  the   neurotransmitter   • Serotonin  has  six  major  circuits  that  spread  from  the  midbrain  of  which   many  end  up  in  the  cortex  and  influence  the  way  we  process  information   • The  serotonin  system  regulates  our  behaviour,  moods,  and  thought   processes.     • Low  activity  is  associated  with  less  inhibition  and  with  less  instability,   impulsivity,  and  the  tendency  to  overreact  to  situations.  Also  associated  with   aggression,  suicide,  and  impulsive  overeating  and  excessive  sexual  behaviour   • Low  serotonin  activity  may  make  us  more  vulnerable  to  certain  problematic   behaviour  without  directly  causing  it     Gamma  Aminobutyric  Acid  (GABA)   • GABA  reduces  postsynaptic  activity,  which  inhibits  a  wide  variety  of   behaviours  and  emotions  and  reduces  anxiety   • GABA  molecules  to  attach  themselves  to  the  receptors  of  specialized  neurons   • The  more  GABA  becomes  attached  to  neuron  receptors,  the  calmer  we   become   • The  GABA  system  rides  on  many  circuits  distributed  widely    throughout  the   brain   • Norepinephrine  is  also  part  of  the  endocrine  system   • Norepinephrine  stimulates  at  least  two  groups  of  receptors  called  alpha-­‐ adrenergic  and  beta-­‐adrenergic  receptors   • Beta  blockers  block  the  beta  receptors  so  their  response  to  a  surge  of   norepinephrine  is  reduced,  which  keeps  blood  pressure  and  heart  rate  down   • Varying  circuits  coursing  through  the  brain  regulate  or  modulate  certain   behavioural  tendencies  not  directly  involved  in  specific  patterns  of  behaviour   or  in  psychological  disorders   • Dopamine  implicated  in  schizophrenia     • Dopamine  turns  on  various  brain  circuits  possibly  associated  with  certain   types  of  behaviour   • Dopamine  circuits  merge  and  cross  with  serotonin  circuits  therefore   influence  many  of  the  same  behaviours   • Dopamine  activity  is  associated  with  exploratory,  outgoing,  pleasure-­‐seeking   behaviours   • Five  receptor  sites  sensitive  to  dopamine   • L  dops  (dopamine  agonist)  are  a  class  of  drugs  that  affect  the  dopamine   circuits   • One  system  that  dopamine  switches  on  is  the  locator  system,  which  regulates   our  ability  to  move  in  a  coordinated  way   • PP.  48-­‐49     Implications  for  Psychopathology   • Psychological  disorders  typically  mix  emotional,  behavioural,  and  cognitive   symptoms,  so  identifiable  lesions  localized  in  specific  structures  of  the  brain   do  not,  for  the  most  part,  cause  them   • Studying  images  of  the  functioning  brain  have  been  applied  to  obsessive-­‐ compulsive  disorder   • Patients  with  OCD  have  increased  activity  in  the  part  of  the  frontal  lobe  of  the   cerebral  cortex  called  the  orbital  surface,  also  in  the  cingulated  gyrus,  and  to   a  lesser  extent,  the  caudate  nucleus   • Damage  or  interruption  in  this  brain  circuit  serotonin,  we  might  find   ourselves  acting  on  every  thought  or  impulse  that  enters  our  heads   • Scientists  interpret  findings  very  cautiously     o Other  individuals  with  the  same  lesion  might  react  differently   o Brain-­‐imaging  studies  are  often  inconsistent  with  one  another  on   many  important  details   o Pinpointing  the  increased  or  decreased  activity  is  difficult  because   brains  differ  in  their  structure   • Attempts  to  replicate  the  results  have  not  been  successful     Psychosocial  Influences  on  Brain  Structure  and  Function   • Disorder  is  caused  by  a  specific  brain  (dys)function  or  by  learned  anxiety  to   scary  or  repulsive  thoughts,  this  view  would  determine  choice  of  treatment   • Directing  a  treatment  and  then  observing  whether  the  patients  gets  between   will  prove  or  disprove  the  accuracy  of  the  theory   • One  overriding  weakness  is  that  an  effect  does  not  imply  a  cause   • Psychosurgery  to  correct  sever  psychopathology  is  an  option  still  chosen   today  on  occasion   • Baxter  treated  patients  with
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