Personality and its disorders

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Personality and its disorders
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Personality

• Extensive literature in genetic research
• Genes make a major contribution to individual
  differences in personality
• Studies mainly done with self report
  questionnaires
• SRQ are remarkably stable over time
• All personality traits show moderate heritability
• Environmental variance makes individuals in the
  same family different from each other

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Personality

• Genetic research focuses on
• Openness to experience (culture)
• Conscientiousness (conformity, will to achieve)
• Extraversion (sociability, impulsiveness,
  liveliness)
• Agreeableness (likeability, friendliness)
• Neuroticism (emotional instability, moodiness,
  anxiousness, irritability)
• Moderate genetic influence in extraversion and
  neuroticism
• Heritability approximately 50 extraversion and
  40 for neuroticism by model fitting
• Environmental influence almost completely due to
  non-shared environment
• Heritability for openness, agreeableness and
  conscientiousness between 35 and 45
• Each one factor could be split in subfactors
  which show moderate heritability as well
• Sensation seeking first factor to show an
  association

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Personality

• Other measure of personality such as peer rating
  show moderate correlations with self-report
  questionnaires
• In children research depends on parent ratings,
  although they are unreliable making findings
  doubtful
• Ratings by observers may be more accurate for
  childrens research
• Adaptability shows better correlation amongst
  twins
• Heritability seems to increase during infancy and
  then becomes stable or continues increasing
  during development

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Personality and social psychology

• Studies have shown genetic influences in most
  aspects of relationships between
  parents-offspring, siblings, friends, etc.
• Genetics plays no role in the type of romantic
  relationships we choose
• Sexual preference shows moderate genetic
  influence
• Moderate genetic influence in self esteem but no
  influence from shared environment (?)
• One does not inherit ideas about different
  aspects of life, we learn them from culture. But
  our genes influence what we put on our tray

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Personality disorders

• Are PDs an extreme manifestation of
  personalities?
• Axis II disorders includes Dx. that date from
  childhood
• Schizotypal personality more frequent in
  relatives of schizophrenic patients
• Concordance of 33 MZ and 4 DZ twins
• Risk amongst 1st degree relatives 11 vs 2
  population
• Rate of schizophrenia and schizotypal PD amongst
  biological relatives vs. adoptive relatives was
  24 and 3 respectively

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Personality disorders

• Schizoid PD
• Pervasive pattern of detachment from social
  relationships and restricted expression of
  emotions beginning in early adulthood and present
  ina a variety of contexts characterized by (4 or
  gt)
• Does not desire or enjoys close relationships
  including familial
• Chooses solitary activities
• Little or no interest in sexual activities with
  another person
• Derives pleasure form few if any activities
• Has no friends or confidants besides 1st degree
  relatives
• Appears indifferent to praise and criticism
• Emotionally cold, detached or flat in his/her
  affect
• Not present exclusively in the presence of other
  disorders

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• Schizotypal PD
• Pervasive pattern of social and interpersonal
  deficits
• acute discomfort and reduced capacity for close
  relationships
• cognitive or perceptual distortions and
  eccentricities of behaviour
• beginning in early adulthood and present in
  various contexts
• Characterized by (4 or more)
• Non delusional ideas of reference
• Odd beliefs or magical thinking incongruent with
  culture
• Unusual perceptual experiences including bodily
  illusions
• Odd thinking and speech
• Suspiciousness or paranoid ideation
• Inappropriate or constrict affect
• Appearance is odd, peculiar or eccentric
• Lack of friends or confidants
• Excessive social anxiety that does not decrease
  with familiarity and is associated with paranoid
  fears rather than self-criticism
• Does not exclusively occur in the presence of
  other disorders

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Personality disorders

• Obsessive compulsive PD
• At least modest heritability
• Part of the spectrum of OCD and other anxiety
  disorders
• Pervasive pattern of preoccupation with
  orderliness, perfectionism, mental and
  interpersonal control
• Rigidity, closed mindedness, lack of efficiency
• Beginning in early adulthood and present in a
  variety of contexts
• Characterized by (4 or more)
• Preoccupation with details and rules, lists,
  schedules, organization to the point that the
  major point of the activity is lost.
• Perfectionism interferes with task completion
• Excessively devoted to work and productivity
  sacrificing leisure and relationships
• Overconscientious, scrupulous, inflexible morals,
  ethics, values
• Unable to discard worn out or worthless objects
  even when they have no sentimental value
• Reluctant to delegate tasks or wrok unless they
  do it his or her own way
• Miserly spending style towards self and others.
  Money is to be hoarded for future catastrophes
• Rigid and stubborn

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Personality disorders

• Antisocial personality disorder
• Pervasive pattern of disregard for and violation
  of the rights of others
• Occurring since age 15 and characterized by four
  or more of the following
• Failure to conform to social norms in
  relationship to lawful behaviours which results
  in multiple arrests
• Deceitfulness, repeated lying, using aliases and
  conning for personal profit or pleasure
• Impulsivity or failure to plan ahead
• Irritability and aggressiveness as per frequent
  fights or assaults
• Reckless disregard for their safety and that of
  others
• Consistent irresponsibility manifested as an
  incapability to maintain work or honour financial
  obligations
• Lack of remorse by being indifferent to or
  rationalizing having hurt, mistreated or stolen
  from another
• Individual is at least 18
• There is evidence of conduct disorder before the
  age of 15
• Does not occur only in the presence of another
  disorder

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Personality disorders

• Antisocial personality disorder
• 1 females and 4 males between ages 13 and 30
• Risk of ASPD is increased x5 in 1st degree
  relatives of ASPD males reared together or apart
• Risk of ASPD is increased ten times in 1st degree
  relatives of ASPD females reared together or
  apart
• Correlation of AS traits amongst MZ twins .50
  vs. DZ twins is .22
• Aggressiveness in children and adolescent shows
  moderate heritability
• Studies of adoptive siblings show evidence of
  significant shared environment (24) and genetic
  (40) influences
• From adolescence to adulthood genetic influence
  increases while shared environmental influence
  decreases

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Personality disorders

• Antisocial personality disorder
• Adoption studies demonstrated that offspring of
  criminals show higher incidence of ASP and drug
  addictions (males) as well as somatization
  disorder (females)
• Only 40 of male criminals and 8 of female
  criminals account for ASPD
• Average concordances for ASPD for MZ and DZ twins
  are 52 and 21 , respectively
• Environment influences criminal behaviour during
  adolescence but not after
• Adoptive parents with criminal convictions do not
  have an influence in the proband, yet biological
  parents who are criminal increase the potential
  for crime in the offspring
• Genetics contributes to criminal behaviours but
  not to alcohol related crimes which tend to be
  more violent

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Personality disorders

• Looking for genes
• DRD4 and novelty seeking behaviours
• DRD4 and hyperactivity
• DRD4 and heroin addiction
• Linkage between long arm of X chromosome and
  homosexaulity
• Monoamine oxidase mutation (Brunners syndrome)
• Other candidate genes COMT, NT receptors, etc.