D R . C H A R M A I N E M I R A N D A C l i n i c a l D i r e c t o r , C o m p a s s C l i n i c C l i n i c a l I n s t r u c t o r , U B C P s y c h i a t r y C l i n i c a l A s s o c i a t e , S F U D R . A D R I E N N E R O M B O U G H P s y c h o l o g i c a l C o n s u l t a n t , C o m p a s s C l i n i c
Intellectual Disability-DSM5
Goals of this talk:
Understand DSM –IV and DSM5 criteria for an
intellectual disability.
Understand the complexities of diagnosing ID and
CLBC Eligibility
What are CLBC eligibility criteria for identification
of a Intellectual Disability?
Based currently on DSM-IV criteria for a
diagnosis of Mental Retardation.
Also true for:
Ministry of Ed.
CYMH
DSM-IV vs. DSM-5
DSM-IV: This disorder is characterized by
significantly subaverage intellectual functioning (an IQ of approximately 70 or below) with onset before age 18 years and concurrent deficits or impairments in adaptive functioning.
DSM-5: Intellectual disability is a disorder with
onset during the developmental period that include both intellectual and adaptive functioning deficits in conceptual, social and practical domains.
Notable Changes to DSM5
1. Terminology
2. Rewording of Age of Onset Criteria
3. Axis 1 diagnosis
4. Reduced Prominence of IQ score
5. Encouraged to add Causal Specifiers
6. Assignment of Severity Specifiers
DSM5: Intellectual Disability
1. Terminology: Intellectual Disability versus Mental
Retardation
2. Rewording of age of onset: Onset in the
“developmental period” versus before age 18
3. Axis changes: Axis II is removed. ID is now an Axis
Defining ID
Reduced Prominence of IQ:
(DSM-4) Criterion A: “Significantly subaverage intellectual functioning: an IQ of approximately 70 or below on an individually administered IQ test.
(DSM-5) Criterion A: Deficits in intellectual functions, such as reasoning, problem solving, planning, abstract thinking, judgement, academic learning, and learning from experience, confirmed by both clinical assessment and individualist, standardized intelligence testing.
“IQ tests scores are approximations of conceptual functioning but may be
insufficient to assess real-life situations and mastery of practical tasks.”
Understanding that an IQ test is only a number.
DSM5: Intellectual Disability
Causal factors e.g., ID associated with genetic
diagnosis of Down Syndrome
Rewording of Adaptive Behaviour Criteria
(DSM-IV) Criterion B: Concurrent deficits or impairments in
present adaptive functioning (i.e. the person’s effectiveness in meeting the standards expected for his or her age by his or her
cultural group) in a least 2 of the following areas: communication, self-care, home living, social/interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health and safety.
(DSM5) Criterion B: Deficits in adaptive functioning that result in a
failure to meet developmental and socio-cultural standards for personal independence and social responsibility. Without ongoing support, the adapative deficits limit functioning in 1 or more
activities of daily life such as communication, school participation and independent living, across multiple environments, such as home, school, work and community. Limited functioning in at
What is IQ and how is it measured?
IQ = Intelligence Quotient as measured on
standardized, interactive tests with trained examiner.
Historical IQ tests measured a child’s mental age and
compared it with their chronological age.
Modern IQ tests compare an individual’s score with a
standardized sample of people with the same-aged to derive a percentile score.
IQ is not a Unitary Construct
On the Wechsler Scale of Intelligence for Children (WISC) and the Wechsler Adult Intelligence Scale
(WAIS), the Full Scale IQ is a summary score based on four Index scores (part scores):
Verbal Comprehension (verbal concept formation, verbal
reasoning, and knowledge, acquired from one’s environment)
Perceptual Reasoning (perceptual and fluid reasoning, spatial
processing and visual-motor integration)
Working Memory (ability to work with information stored
temporarily in memory)
Processing Speed (ability to quickly and correctly scan,
What is the General Ability Index (GAI)?
Verbal Comprehension (VCI) Perceptual Reasoning (PRI) Working Memory (WMI) Processing Speed (PSI)
Full Scale IQ (FSIQ)
General Ability Index (GAI)
Scaled Score 73 87 77 94 78 76 Scaled Score 122 116 97 80 108 123
• GAI: A summary score comprised of the Verbal Comprehension
Other considerations
How to apply the DSM IV and DSM 5. Does the person meet diagnostic criteria?
history/interviews/file review, IQ and adaptive functioning test
scores
What are the differential diagnoses?
How will a diagnosis affect access to supports/services?
Differential Diagnoses for ID
Global Developmental Delay (GDD): identifies a child aged 5 or under who is failing to meet expected
developmental milestones in several areas of intellectual functioning but is unable to undergo systematic
intelligence testing. Retesting is required.
Neurocognitive Disorders: identify an individual who has experienced a significant decline in cognitive ability and adaptive functioning/independence in everyday
activities. Due to an illness, trauma, medical diagnosis. (e.g. Alzheimer's, vascular disease, head injury)
Legal Influence on Society’s Idea of ID
2002: Atkins: court decided that a person with MR could
not be executed (thereafter called the Atkins death penalty exemption)
2005: Hawthorne: IQ within low average range, but
ADHD, deemed eligible for Atkins exemption.
2007: Vidal case: Verbal IQ in the 50’s, but Performance
IQ average to high average. FASD dx. Deemed to be eligible for Atkins exemption
2008: Hearn case, V/P split, and FASD. Also deemed
The role of clinical judgment
DSM-5 Criterion A: Deficits in intellectual functions,
such as reasoning, problem solving, planning, abstract thinking, judgement, academic learning, and learning from experience, confirmed by both clinical assessment and individualist,
standardized intelligence testing.
Blurring of diagnostic boundaries?
L E T ’ S P R A C T I C E !
Case Study 1: “G” - aged 16 years
G is diagnosed with autism, ADHD, Oppositional Defiant Disorder, Anxiety Disorder, and Soto’s Syndrome
G would light fires in his room and smear feces on the walls.
He used knives to cut and destroy things. He damaged flooring and walls in his family home.
Due to his extensive care needs and unpredictable
behaviour, G required 24/7 supervision. During his stay at an inpatient psychiatric unit, G often required 2:1
support.
G’s WISC-IV Index Scores
WISC IV Index Standard
Score PercentileRank 95% Confidence Interval DescriptionQualitative
Verbal Comprehension (VCI) 91 27 84 – 99 Average Perceptual Reasoning (PRI) 85 16 78 – 95 Low Average Working Memory (WMI) 71 3 66 – 82 Borderline Processing Speed (PSI) 50 <0.1 47 – 63 Extremely Low
Full Scale IQ (FSIQ) 72 3 67 – 79 Borderline General Ability Index (GAI) 86 18 80 – 93 Low Average
G’s Adaptive Functioning & Challenging
Behaviour Scores
G’s everyday adaptive living skills and challenging behaviours were assessed using the
SIB-R (a common care-giver report measure).
The Broad Independence score is a summary score for overall adaptive living skills.
The General Maladaptive Index score is a score summarizing challenging behaviours and
need for behavioural support/supervision. G’s social and emotional maturity was reflective of a much younger child. His need for direct supervision was high.
Functionally, G’s abilities/skills corresponded to his Full Scale IQ score.
Composite/ Subdomain Standard
Score Percentile Qualitative Description EquivalentAge
Broad Independence 40 0.1 Well Below Average 6:4 Generalized
Maladaptive Index 50 --- Very Serious
---Internalized 32 --- Serious
---Asocial 42 --- Very Serious
---G’s Academic Scores
Subtests Scaled ScoreStandard/ Percentile DescriptionQualitative Grade Equivalent Age Equivalent Word Reading 102 55 Average 12.4 17:0-19:11 Reading Comprehension 97 42 Average 8.7 13:0 Math Problem Solving 74 4 Below Average 4.5 9:4
Would G meet DSM-IV criteria for MR?
Would G meet DSM5 criteria for ID?
Summary of G’s Assessment Results
When there’s variability in Index scores, consider:
Functional Impairment
Consistency with Full Scale IQ Confounding variables
Age and access to services
One single Index score is not a good representation of strengths and weaknesses.
Use Full Scale IQ unless there is a valid reason not to. Some skills/scores might be considered splinter skills
and not reflective of overall dysfunction
E.g., Children with Williams Syndrome show strengths in language
Summary of G’s Assessment Results
In everyday life, G is functioning below the level of a
6 year-old.
G’s reactivity and impulsivity are even lower than
this level. His functioning is impaired because of
very significant impairment in executive functioning, well below average social-emotional maturity, and severe reactivity and impulsivity. G acts without
thinking, is reactive, engages in antisocial behaviours and encourages others to do the same.
Case Study 2: “Stephie” - aged 22 years
Head injury at age 14.
Diagnosed with an acute psychotic episode at age 16. Extremely disordered behaviour:
History of SIB: She was reported to carry around a knife and used it to
cut herself.
Paranoid, obsessive and repetitive thoughts and behaviours, many
centering around her fear of contamination.
Impulsive stealing
Disordered eating, including bingeing and purging, hoarding food and
refusing to eat.
Ongoing issues with incontinence and soiling. history of smearing feces
on the walls.
Does not plan her clothing for the weather or social setting. At times, she
has exposed herself inappropriately. During her stay at the psychiatric inpatient unit, she would wear men’s underwear on her head.
Demonstrates baby-like behaviours, such as using a soother, eating baby
History of Stephie’s IQ Scores
Year Full Scale IQ
Score Age
2006 80 16
*Exact Full Scale IQ score not reported due to discrepancies between Index scores.
Stephie was found to meet criteria for a Mild Intellectual Retardation in 2009
2009 <70* 19
Stephie’s Index Scores (February 2012)
WAIS IV Index Standard
Score PercentileRank 95% Confidence Interval DescriptionQualitative
Verbal Comprehension (VCI) 54 0.1 50 – 63 Extremely Low Perceptual Reasoning (PRI) 78 7 73 – 86 Borderline Working Memory (WMI) 58 0.1 54 – 69 Extremely Low Processing Speed (PSI) 72 3 66 – 83 Borderline
Stephie’s Adaptive Functioning
Stephie’s adaptive functioning was assessed using
the SIB-R
Composite/ Subdomain Standard
Score Percentile Qualitative Description Age Equivalent Broad Independence 5 <0.1 Well Below Average 5:1
Motor Skills 10 <0.1 Well Below Average 3:10
Social/Communication 36 0.1 Well Below Average 6:3
Personal Living 25 0.1 Well Below Average 4:8
Does Stephie meet criteria for diagnosis under
DSM-IV?
Under DSM5?
Summary of Stephie’s Assessment Results
Based on the results of the assessment, Stephie was
felt to present with a profile in keeping with that of a Mild Mental Retardation (DSM-IV). Results of
cognitive testing were generally consistent with those documented in her most recent previous assessment (2009).
Does onset of psychosis at age 16 change the ID
diagnosis?
If Stephie’s psychosis started at age 25 and ‘brought
Case Study 3: “Nancy” age 6
Presenting Issues
Confirmed pre-natal alcohol and poly-substance exposure.
One of 7 children from bio-mother.
Family hx: Bio-mom described as “generally slow”, 3 siblings have ASD.
History of placements in foster care (poverty/neglect, exposure to domestic violence)
Moderate speech and language delays
Behavioural concerns (tantrums, self-harm, difficulty with changes in routine, hyperactivity)
Behavioral Observations from Testing
Attention comes in and out of focus
Tends to be impulsive
Likes some tasks but dislikes others. Not very
engaged when she doesn’t like a task.
Overall: Sweet, friendly, socially-responsive. Enjoys
Nancy’s Index Scores
WPPSI- IV Index Standard
Score PercentileRank 95% Confidence Interval DescriptionQualitative
Verbal Comprehension (VCI) 62 1 57-72 Extremely Low Visual Spatial (VSI) 73 4 67-85 Borderline Fluid Reasoning (FRI) 80 9 74-89 Low Average Working Memory (WMI) 76 5 70-86 Borderline Processing Speed (PSI) 77 6 71-90 Borderline
Nancy’s Adaptive Functioning
G’s everyday adaptive living skills were assessed using the ABAS-II (a common care-giver report measure).
Composite Standard
Score Percentile Qualitative Description
General Adaptive
Composite 65 1 Well Below Average
Conceptual 69 2 Well Below Average
Social 65 1 Well Below Average
Does Nancy meet criteria for diagnosis under DSM-IV?
Under DSM5?
Summary of Nancy’s Assessment Results
Based on the results of the assessment, Nancy was
NOT felt to present with a profile in keeping with
MR (DSM-IV) or ID (DSM-5).
Her profile was found to be more consistent with
FASD.
Questions for Discussion
If someone has normal development until the age of 7 and has a head injury that arrests their development, would they be
considered eligible for a diagnosis of an Intellectual Disability? If someone has a head injury at age 30 would they be
eligible for a diagnosis of an Intellectual Disability? Should they be eligible for CLBC support?
If drug use has resulted in cognitive results scoring below 70, does this individual meet criteria for an intellectual
disability? Would age of the drug use change the decision for diagnosis?
Take Home Message
It takes a Clinician not a Technician to determine ID
in these difficult cases. We have to consider multiple factors, including age, support requirements,
variability in functioning, and course of presentation.
In any report where the cognitive presentation is
unusual, the summary should clearly outline the clinician’s thought process and why ID was
References & Recommended Reading
American Psychiatric Association. (2013). DSM5 Intellectual Disability Fact Sheet.
Bergeron, R., & Floyd, R.G. Broad Cognitive Abilities of
Children with Mental Retardation: An Analysis of Group and Individual Profiles. American Journal on Mental
Retardation 111(6): 417-432. November 2006.
Carulla, LS., et al. Intellectual Developmental Disorders: Towards a New Name, Definition and Framework for “Mental Retardation/Intellectual Disability” in ICD-11. Word Psychiatry 3 (10): 175-180. October 2011.
Cheung, N. Defining Intellectual Disability and
Establishing a Standard of Proof: Suggestions for a National Model Standard. Health Matrix 23 (1). 2013.
