THE NOSOLOGY OF CHILD

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• THE NOSOLOGY OF CHILD ADOLESCENT PSYCHIATRY
• Barry Nurcombe, M.D.
• Emeritus Professor
• Child and Adolescent Psychiatry
• The University of Queensland

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• The tendency has always been strong to believe
  that whatever receives a name must be an entity
  or being, having an independent existence of its
  own. And if no real entity answering to the name
  could be found, men did not for that reason
  suppose that more existed, but imagined that it
  was something particularly abstruse and
  mysterious.
• John Stuart Mill

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• Whenever we have made a word to denote a certain
  group of phenomena, we are prone to suppose a
  substantive entity beyond the phenomena.
• William James (1890)

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TOPICS

• The metatheory of DSM-IV
• Categorical disorder or dimensional traits ?
• Wakefields concept of harmful dysfunction
• Distinctive categories or fuzzy prototypes ?
• What do we know about conduct disorder?
• Does the concept of harmful dysfunction fit
  conduct disorder ?
• Stabilizing evolutionary selection and
  maladaptiveness
• An evolutionary-developmental, dimensional model
  of conduct disorder

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DSM-III AND-IV

• Introduced at a time when psychiatry had to be
  remedicalized
• Coincident with the displacement of
  psychoanalysis by neurobiology
• Mental disorders are qualitatively distinct
  entities characterized by
• ? definable behavioural / psychological
  syndromes
• ? causing distress / disability

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DSM-III AND-IV(Continued)

• ? not merely expectable responses to
  events
• Disorders are identified in accordance with
  essential and optional /- symptom counts
• DSM is supposed to be atheoretical
• It has no developmental dimension

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THE METATHEORY OF DSM

• Categorization is inevitable and utilitarian
• Mental disorders are finite and discrete
  categorical entities
• Mental disorder is caused by endogenous
  dysfunction
• Biological dysfunctions require biological
  remedies

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PAUL MEEHLS COMPROMISE

• Mental disorders are hypothetical categorical
  constructs
• The constructs (taxa) should be tested using
  taxonometric techniques
• There are no sharp boundaries at the level of
  symptoms (as in DSM-IV)
• But there may be discrete latent entities
• The predictive validity of a syndrome is a
  necessary but insufficient condition to establish
  it as a taxon

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PAUL MEEHLS COMPROMISE(Continued)

• Many true taxa are probably not biologically
  determined
• DSM-IV is likely to be a mix of latent taxa and
  dimensional syndromes

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MENTAL DISORDER AS HARMFUL DYSFUNCTIONJerome
Wakefield (1992a,b 1995 1999)

• Mental disorder is the result of-
• the failure of an internal mechanism (e.g.,
  reactive aggression) to perform the functions for
  which it was naturally selected (a scientific
  judgement),
• thus causing harm to the individual (a social
  judgement)

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CRITICISMS OF THE POSTULATE OF HARMFUL
DYSFUNCTIONLillienfeld and Marino (1995, 1999)

• Disorder is a concept lacking in defining
  features. It has fuzzy boundaries organized
  around idealized mental prototypes
• These prototypes may or may not mirror reality
• Categorical reasoning is based on a subjective
  judgement as to whether or not the person fits a
  fuzzy prototype

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EXAMPLE DSM-IV CONDUCT DISORDER

• Repetitive, persistent violation of the rights of
  others or of societal norms or rules, with 3 or
  more of the following criteria in the last 12
  months, and at least 1 in the past 6 months-
• ? Aggression (7)
• ? Property destruction (2)
• ? Deceitfulness / theft (3)
• ? Serious rule violations (3)

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CONDUCT DISORDER AND HARMFUL DYSFUNCTION

• It is certainly harmful
• But where is the dysfunction ?
• There are multiple dysfunctions
• ? attachment
• ? empathy
• ? conscience formation
• ? emotional regulation / impulse
  control

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CONDUCT DISORDER AND HARMFUL DYSFUNCTION(Continu
ed)

• ? verbal intelligence / learning
• ? social attribution
• ? self image
• Are there a number of conduct disorders ?
• This question will not be elucidated while the
  distinguishing features of CD are little more
  than a rap sheet

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WHAT DO WE KNOW ABOUT CONDUCT PROBLEMS?

• Prevalence rate 8.2 in boys, 2.8 in girls
  (Offord et al, 1986)
• Marked comorbidity with ADHD, LD, SAD, Anxiety,
  and Depression
• Known risk factors

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RISK FACTORS

• Crowded, impoverished inner city areas
• Family stress, transition, unemployment
• Marital discord
• Coercive parenting
• Physical and sexual abuse
• Hostile attributional bias
• Neuropsychological deficits
• Academic underachievement
• Deviant peers
• Early drug use

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WHAT DO WE KNOW ABOUT CONDUCT PROBLEMS ?

• Parental psychopathology common
• Genetic inheritance unclear
• But likely to be important in psychopathy
• Heterotypic continuity
• Developmental trajectory
• ? 25 ODD ? CD
• ? 90 of CD had ODD
• ? 25 40 of CD ? ASPD as adults

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WHAT DO WE KNOW ABOUT CONDUCT PROBLEMS(Continued)

• Early Onset and Late Onset types (Moffitt, 1993,
  1996)
• ? Risk factors congregate in Early
  Onset Type
• ? Late Onset Type may be time-
  limited
• ? However, Late Onset is the rule
  among females

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TESTS OF THE CATEGORICAL MODEL OF CD

• Robins Evoy (1990) The symptoms of CD as
  reported retrospectively by ECA subjects predict
  adolescent / adult substance abuse in a
  cumulative, linear fashion, not in a threshold
  manner
• Moffitt (1993) Age of onset, ADHD,
  neuropsychological dysfunction and family discord
  are joint markers of two divergent classes (Early
  Onset and Late Onset)

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TESTS OF THE CATEGORICAL MODEL OF CD(Continued)

• Fergusson Horwood (1995) Dimensional
  representations of symptoms of disruptive
  behaviour disorder have greater predictive
  validity than their categorical counterparts do

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AN EVOLUTIONARY APPROACH

• Most mental characteristics have evolved as a
  result of the stabilizing selection of polygenic
  traits, producing continuous normal distributions
• Until recently, males were naturally selected for
  their potential as hunter / warriors
• Hunter / warriors fit a particular kind of
  ecological niche

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AN EVOLUTIONARY APPROACH(Continued)

• Successful warriors kill their enemies, take
  their women, and breed
• In a technological society, the warrior role is
  no longer adaptive

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CONDUCT DISORDER AND THE HUNTER / WARRIOR

• Conduct Disorder Hunter / Warrior
• Aggressiveness Aggressiveness
• Destructiveness Rapine and pillage
• Stealth, deceit Stealth, cunning
• Rule violation Self-reliance
• Gangs Warrior bands

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AN EVOLUTIONARY DEVELOPMENTAL MODEL

• Factor Structure Behaviour
• Inheritance Hunter-warrior genes
  Aggressiveness
• Neglect (0-3) Disrupted attachment
  Impaired empathy
• Coercive rearing (2-6) Hostile attributional
  Oppositionalism
• bias
• Abuse/assault PTSD Explosiveness
• (2-16) Coercive sexual
• behaviour
• Poor verbal Neurocognitive Learning
  problems
• stimulation (0-5) impairment
• Rejection by peers Outlaw status School
  failure,
• and teachers (5-9) truanting,
  dropout
• Deviant peers (9-16) Male bonding Gang
  membership
• Alcohol and drugs Drug use Substance
  abuse
• (12-16)

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CHARACTERISTICS OF THE EVOLUTIONARY DEVELOPMENTAL
MODEL

• Not Categorical
• A dimensional typology depending on the
  developmental timing of each dimension and the
  extent to which it operates
• Clear implications for goal-directed prevention
  and treatment

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DISRUPTIVE BEHAVIOUR DISORDERA SYNDROME OF
CONTINUOUS DIMENSIONS

• Reactive aggression / impulsivity / emotional
  dysregulation
• Impaired attention
• Neurocognitive defects / learning problems
• Oppositional behaviour / rule breaking

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DISRUPTIVE BEHAVIOUR DISORDERA SYNDROME OF
CONTINUOUS DIMENSIONS(Continued)

• Callousness / impaired empathy / predatory
  aggression
• Traumatic anxiety / depression
• Hostile attribution

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THE CONCEPT OF A SYNDROME OF DIMENSIONAL CONTINUA

• Each continuous dimension has a different gene /
  environmental basis
• The environments that trigger different gene
  expressions differ
• Different dimensions emerge at different times
• Early dimensions are syndrome markers

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IMPLICATIONS FOR RESEARCH AND TREATMENT

• The gene / environment interaction for each
  dimension can be studied
• The neurobiological basis of each dimension can
  be studied
• The particular environments that foster gene
  expression can be elucidated

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IMPLICATIONS FOR RESEARCH AND TREATMENT(Continue
d)

• Different early-emerging dimensions may be
  modifiable by drugs, or psychosocial
  interventions, or both
• The sooner, the better