1. ADHD and PDD
The Overlap Between Attention-Deficit Hyperactivity Disorder and Pervasive Developmental Disorders
Eileen Matias Davis, B.A.

2. ADHD & PDD Outline ADHD, PDD, and the DSM-IV-TR
Evidence for comorbidity
ADHD Sx in PDD
PDD Sx in ADHD
Theory of Mind and Executive Functioning
Psychostimulants in Tx of PDD
And other treatment implications
Different potential models for the relationship between ADHD and PDD
Dual diagnosis

3. ADHD and PDD
ADHD is a neuropsychological disorder characterized by developmentally inappropriate levels of hyperactivity, impulsivity, and inattention.
Combined Type
Predominately Inattentive Type
Predominately Hyperactive Type
PDD is characterized by delays and deficits in the development of social interaction, communication skills, and cognitive abilities.
Autism
Asperger Syndrome
PDDNOS
Childhood Disintegrative Disorder
Rett Syndrome

4. Onset ADHD Sx must be present before the age of 7
Although this is a somewhat arbitrary number, we do know that ADHD Sx must begin at least in childhood
Concerns often begin when the child starts pre-Kindergarten
Initial diagnosis often occurs in preschool years
PDD
Sx should be present in the first years of life
Late onset: after 3 years
Parents usually start expressing concern at months
Diagnosis often does not occur until the child is 3 or 4

5. DSM-IV-TR ADHD Asperger’s
6+ Sx of inattention (i.e. careless mistakes, difficulty sustaining attn, difficulty organizing tasks, etc.) OR
6+ Sx of hyperactivity/impulsivity (fidgets with hands or feet, acts as if driven by motor, talks excessively difficulty awaiting turn, etc.)
Impairment in 2+ settings
Impairment in social, academic, or occupational functioning
Asperger’s
Qualitative impairment in social interaction (2+) (failure to develop peer relationships appropriate to developmental level, lack of social/emotional reciprocity, etc)
Restricted repetitive and stereotyped patterns of behavior, interests, and activities (1+) (apparently inflexible adherence to specific, nonfunctional routines or rituals; stereotyped and repetitive motor mannerisms, etc,)
Impairment in social, occupational, or other areas of functioning
No significant delay in language

6. DSM-IV-TR Autism PDDNOS
Qualitative impairment in social interaction (impaired use of non-verbal behaviors, lack of social/emotional reciprocity, etc.)
Qualitative impairment in communication (delay in/lack of development of spoken language, lack of make-believe play, etc.)
Restricted repetitive and stereotyped patterns of behavior, interests, activities (persistent preoccupation with parts of objects, encompassing preoccupation with stereotyped patterns of interest, etc.)
Delays or abnormal functioning in social interaction, language as used in social communication, or symbolic/imaginative play
Sx present by age 3
PDDNOS
Severe and pervasive impairment in the development of reciprocal social interaction
Impairment in either verbal or nonverbal communication skills or presence of stereotyped behavior, interests, and activities
criteria not met for specific PDD
Includes "atypical autism" (presentations that do not meet the criteria for Autistic Disorder because of late age at onset), atypical symptomatology, or sub-threshold symptomatology

7. High-Functioning PDD IQ ≥ 70
Mostly associated with PDD-NOS and Asperger’s
Approximately 92% of kids with PDD-NOS are high-functioning (Chakrabarti & Fombonne, 2001)

8. PDD-NOS No positive criteria
Milder conditions that do not fit into the other PDD categories are often given this label
No clear cutoffs for distinguishing kids with PDD-NOS from normal kids or kids with other psychopathology
This can make the distinction between PDD-NOS and ADHD particularly difficult because the social interaction difficulties that often occur in ADHD can be interpreted as PDD symptoms
A child with ADHD that also shows some PDD Sx may be given the PDD-NOS Dx instead
Conversely, may kids with PDD-NOS are first given an ADHD Dx

9. Exclusionary Criteria
ADHD cannot be diagnosed in children if it occurs exclusively within the course of PDD (Criterion E).
Because PDDs are chronic and unremitting conditions that begin very early in life, there is virtually no period where the ADHD symptoms could manifest alone in most kids with PDD.
There is much debate about whether ADHD should be diagnosable in children with PDD.
According to many clinicians, there is a significant subset of kids who the DSM-IV can’t appropriately diagnose as it stands.

10. Evidence for Comorbidity

11. Disclaimer: Using DSM-III-R
ADHD Sx in PDD
Frazier et al. (2001)
Structured Diagnostic Interviews of all kids referred to psychopharmacology clinic due to behavior problems
83% of 60 PDD kids also met criteria for ADHD
PDD kids had similar PDD Sx regardless of ADHD comorbidity
ADHD kids had similar ADHD Sx regardless of PDD comorbidity
These findings suggest that the two disorders are independent and provides support for comorbidity
Disclaimer: Using DSM-III-R

12. ADHD Sx in PDD Goldstein & Schweback (2004)
Retrospective chart review of kids with PDD
16 (59%) met DSM-IV criteria for ADHD
7 (26%) combined type
9 (33%) inattentive type
PDD + ADHD did not show significantly greater impairment (small sample size?)

13. ADHD Sx in PDD Lee & Ousley (2006)
Systematic chart review of children and adolescents with ASD
65 (78%) – met DSM-IV criteria for ADHD
64% combined type
14% inattentive type
5% hyperactive type

14. ADHD in Kids with PDDs Yoshida & Uchiyama (2004)
67.9%
22.1%
Within PDD-group comorbidity:
Autistic Disorder – 58%
Asperger’s – 67%
PDDNOS – 88%
*All subjects were outpatients at the Yokohama Psycho-Developmental Clinic in Japan

15. Summary of ADHD Sx in PDD
Many kids with pervasive developmental disorders meet criteria for ADHD
These symptoms appear to be independent of PDD core features
It remains unclear whether PDD + ADHD is associated with greater impairment than PDD alone

16. Comorbidity: A Case Study “Ichiro”
Ichiro is a 10-year-old male. His motor development was normal: He first walked at the age of 10 months. However, his first words came at 18 months. Delayed verbal skills, impairment in social interactions, and hyperactivity at 18-months suggested autism. At 2 years, he began making two-word phrases. When he entered kindergarten at age 4, hyperactivity decreased gradually, and he could participate in group activities. By that time, he appeared to be just an active boy with no developmental problems, and consultations stopped. Hyperactivity recurred when he moved and changed kindergartens. His mother visited an educational consultation center to request a behavioral evaluation when he was 5 yrs old. No developmental delays were noted. Ichiro was markedly hyperactive from the first day of elementary school. He could not remain seated and spoke without permission during class. He also had difficulties with peer interactions, although he enjoyed conversations with adults, including teachers.
Ichiro was diagnosed with ADHD by a psychiatrist when he was 6 years old. Methylphenidate therapy (10 mg/day) began at 6 years and 2 months, and his behavior improved remarkably. During class, he could remain seated and raise his hand before speaking. He seldom had trouble with other children, but he could not make friends. Six months later the medication was discontinued, and behavioral problems recurred. Restarting methylphenidate relieved the problems rapidly.

17. Comorbidity: A Case Study “Ichiro”
At that time, Ichiro’s sister was diagnosed with Asperger’s syndrome. This led Ichiro’s mother to notice that his behavior seemed to match the Asperger’s profile as well. Ichiro was re-evaluated at age 7. During his visit, the doctor played a game with him, the object of which was to find a hidden coin in each other’s palms. The boy concealed the coin in one hand by making a fist, but kept the other hand open. When the doctor explained: “If you leave one hand open, I can guess where the coin is,” Ichiro took the words literally, at face value. Ichiro opened both hands.
During the interview, Ichiro repeated the expression, “Oh, really?” unnaturally often, and his intonation was too strong, so his speech sounded teasing.
His mother complained of difficulties in interacting with him. For instance, when she said angrily that she would leave home because he never straightened his room, he would respond: “Oh, really? Please tell me where the restaurant is.” The boy had no friends at school, but did not seem to care unless he was bullied. He played alone at home by acting out all parts of a role play, had much interest in atoms and molecules, brushed his teeth for exactly 3 minutes, and had a habit of swinging a string. These stereotyped bx/interests were not observed at school.

18. Comorbidity: A Case Study “Ichiro”
The teachers thought that his poor social skills were secondary effects of ADHD. His teacher was primarily concerned about Ichiro’s hyperactivity, impulsivity, and inattention. Ichiro was always squirming in his seat. He was often blamed for leaving the line at morning assembly. He frequently left or lost things at school. His teacher described in a report card that the boy interrupted his classmates whenever an idea occurred to him, and that he often forgot to do assigned tasks.
He showed poor gross and fine motor skills. Results of WISC-III showed a full-scale IQ of At present, Ichiro continues taking methylphenidate (40mg/day). He has no apparent troubles with peers, although he does not initiate play. The medication has been effective for inattention as well as for hyperactivity. His careless mistakes on tests have decreased, and he loses fewer things at school. He is an academically high achiever.
Although Ichiro’s Sx indicate a diagnosis of Asperger’s, he was instead diagnosed with PDDNOS because he also met diagnostic criteria for ADHD.

19. Discussion: What are some of the important/interesting issues and concerns that you identified in this case study?

20. Case Study “Jiro” No spoken language until 25 months
Vocabulary rapidly increased starting at 3 years
Poor eye contact, hyperactivity, restricted interest in letters early on
In school, could interact with peers as he skillfully drew pictures of pipes and parking lots
Poor conversational skills and seldom spoke at school
Looked vacant and often forgot things
Restricted interest in fighter aircraft
Rapid increase in verbal production at age
9 or 10, but qualitative impairments in
social interaction and communication became
obvious again
He was willing to obey classmate’s directions in
order to gain acceptance

21. Case Study “Jiro” Diagnosed with Asperger’s syndrome at age 10.
He was told that his parents and doctors wanted to help him find ways to better enjoy life
At the next interview, he presented his doctor with a note asking four questions:
“I easily forget what’s been said to me. Why?”
“I cannot remember mathematical formulae. Why?”
“I cannot remember [Japanese characters]. Why?”
“I know many words, but cannot talk freely to people. Why?”
As he explained the letter, he began to cry. Jiro appeared more distressed by his symptoms of inattention than my impairments due to PDD, although the PDD would have a greater influence on his later life.

22. Discussion: What are some of the important/interesting issues and concerns that you identified in this case study?

23. PDD Sx in ADHD Social Dysfunctioning Communication Impairments
Impairments in social interactions with peers
Inability to conceive other people’s feelings and thoughts (empathy)
Communication Impairments
Difficulties with certain aspects of pragmatic language
Inappropriate initiation of conversation
Inappropriate use of syntax
Odd forms of speech
Problems with nonverbal communication
Restricted Patterns of Bx, Interests, Activities
Stereotyped hand and body movements
Nijmeijer et al. 2008

24. PDD Sx in ADHD Parent Report - Autism Criteria Checklist
Clark et al, 1999

25. Social Dysfunctioning
Deficits that appear directly related to ADHD core Sx:
Blurting out answers
Interrupting or intruding on conversations of others
Failing to attend to important social cues
Handling frustration in impulsive/aggressive manner
Deficits that may be due to other problems in social skills and social information-processing:
Failure to comprehend the impact of one’s actions on others
Misinterpreting social information
Possessing a limited repertoire of social responses
Difficulty monitoring and responding to the ongoing stream of one’s social interactions
(Greene et al., 1996)

26. Social Dysfunctioning
Green et al, 1996
22% of a sample of ADHD (vs. 0% of non-ADHD controls) were classified as “socially disabled”
Used standardized discrepancy score between expected scores (based on IQ) and observed scores on a measure of social functioning
ADHD + Socially disabled
greater impairment than non socially disabled ADHD kids on measures of social functioning and patterns of psychiatric comorbidity
Suggests subset of ADHD kids with severe social dysfunction
Does this represent a sub-type of ADHD that is more closely linked to PDD? Or perhaps comorbid ADHD/PDD?
More research is needed in this area

27. PDD Sx in Hyperkinetic Disorder P.J. Santosh, et al. (2004)
Hyperkinetic Disorder is an ICD-10 diagnosis that is ultimately a subset of ADHD combined type (inattentiveness, hyperactivity, and impulsivity all present in the same child).
Identified two social impairment subtypes:
Relationship Difficulties
Social Communication
Difficulties
P.J. Santosh, et al.

28. Relationship Difficulties showed strong association only with conduct problems and affective symptoms, as well as much greater association with environmental stressors.
Social Communication Difficulties were associated with repetitive behaviors, speech and language difficulties, developmental difficulties (all PDD Sx), as well as affective symptoms, ADHD, and conduct problems.

29. PDD Sx in Hyperkinetic Disorder
HKD vs. psychiatric controls:
40% (vs. 18%) had difficulties in social reciprocity
24% (vs. 17%) had speech and language difficulties
9% (vs. 5%) repetitive behaviors and overcircumscribed interests
Significantly more HKD kids had the PDD triad
‘Difficulties in social reciprocity’ was the most common PDD domain and showed the highest discrepancy between HKD and psychiatric controls

30. Summary of PDD Sx in ADHD
Many children with ADHD show symptoms of PDD, particularly difficulties in social reciprocity
Not all social deficits in kids with ADHD can be accounted for by core features of the disorder
A subset of kids with ADHD (perhaps a more severe variant) who are “socially disabled” may warrant a comorbid PDD diagnosis
The social difficulties in these kids may be differentiated from social difficulties commonly found in ADHD that are more closely associated with conduct problems
Social Communication Difficulties (PDD) vs Relationship Difficulties (ODD/CD)
It remains unclear whether the social difficulties in ADHD are only similar in presentation to PDD or if they also share similar pathology

31. Evidence from Theory of Mind and Executive Functioning
More ADHD/PDD Overlap
Evidence from Theory of Mind and Executive Functioning

32. Theory of Mind
Results from ToM and emotion recognition tasks tend to confirm the findings of a lack of awareness of the feelings of others in children with ADHD
ToM
“The ability to attribute mental states, such as beliefs, desires, and intentions to oneself and to other people and thereby to understand and predict behavior.”
Most children with ADHD were found to be as impaired on these tasks as children with high-functioning autism and PDDNOS and more impaired than both normal and clinical controls.
Especially with regard to second order mentalizing skills (the ability to predict beliefs about beliefs)
Buitelaar et al. (1999)

33. Executive Functioning
EF Deficits (deficits in mental control processes) are considered central deficits in both ADHD and PDD.
Some studies have shown that inhibition deficits may be specific to ADHD and that children with PDD more often show problems with planning and flexibility
However, these findings have not been consistently replicated and may seem inconsistent with what we know about these disorders
Jonsdottir et al. (2006)
EF deficits in kids with ADHD were not related to ADHD symptoms but instead to comorbid depressive and autistic symptoms.

34. Treatment

35. Psychostimulants in PDD Handen, Johnson, & Lubetsky, 2000
Double-blind, placebo-controlled study of 13 children with autism and symptoms of ADHD
Given placebo, .3mg/kg MPH, and .6mg/kg MPH in random order for seven days each
Measures:
Conners Teacher Scale, IOWA Conners Teacher Rating Scale, Aberrant Behavior Checklist, Child Autism Rating Scale, Side Effects Checklist
61.5% were MPH responders
50%+ decrease on Teacher Conners Hyperactivity Index
Decreased inattention, hyperactivity, and aggression
Gains in “odd, bizarre behavior” and “repetitive speech”

36. Psychostimulants in PDD
A number of adverse
side effects reported by
teachers
Many of these side
effects were reported at
high rates during placebo
trial
Most remained stable
across drug conditions
Handen, Johnson, & Lubetsky, 2000

37. Psychostimulants in PDD, cont.
Quintana et al. (1995)
10 kids received either 10mg MPH or placebo, followed by 2 weeks of 20mg MPH
Significant improvements on Conners and Aberant Behavior Checklist
Side effects did not differ between drug and placebo conditions
Stigler et al. (2004)
Retrospective chart review of 195 children with PDDs
<25% responded to first stimulant trial
>50% experienced significant adverse effects
Pts with Asperger’s were significantly more likely to respond to stimulant trial

38. Psychostimulants for Tx of PDD: Summary
There is some evidence that stimulant meds can be beneficial for some kids with PDD+ADHD
Reports of side effects are cause for concern
Need for more research looking at treatment response and side effects within homogenous groups of children with PDD + ADHD as compared to children with ADHD only
Perhaps psychostimulants can be an efficacious treatment for ADHD Sx occuring in some PDD diagnoses (i.e. PDDNOS or Asperger’s) more than others
No research on other treatments for ADHD Sx in PDD

39. Treating ADHD + “Social Disability”
If the social impairments in a subset of kids with ADHD resemble those in kids with PDDs in their severity, perhaps some of the same PDD Tx approaches can be applied to treating these deficits in the ADHD population.
These children may require Tx that differ in “form, frequency, and intensity” from other ADHD kids and perhaps more closely resemble Tx approaches for PDDs
What are some of the different treatment approaches that may be used for this subset of kids (perhaps borrowed from PDD literature)?

40. Modeling the ADHD/PDD Relationship

41. ADHD + Social Disability
ADHD/PDD Continuum
Some researchers have suggested that ADHD falls on the milder end of the PDD spectrum
An alternative possibility is that ADHD and PDD represent two separate spectrums with overlapping Sx.
ADHD
Asperger’s
PDD-NOS
Autism
PDD-NOS
Autism
Asperger’s
ADHD Inattentive
ADHD Combined
ADHD + Social Disability

42. ADHD + Social Disability
ADHD/PDD Continuum
A third alternative may be that the presence of severe social impairments in kids with ADHD, or extreme inattention and/or hyperactivity/impulsivity in kids with PDD actually represents the co-occurrence of the two disorders.
ADHD Inattentive
ADHD Combined
ADHD + Social Disability
PDD-NOS
Autism
Asperger’s

43. Benefits of Dual Diagnosis
Explains co-occurring symptoms that cannot be explained by PDD alone or ADHD alone
Grants full acknowledgement of impairments and validates concerns
Allows for treatment plans that include the treatment of ADHD core symptoms in PDD and PDD symptoms in ADHD
Compensatory behaviors can be taught for ADHD Sx
Providers will pay for services in Tx of comorbidities
Others?

44. Dual Dx would be inappropriate/unnecessary if:
Inattention and hyperactivity-impulsivity in PDD cases were due specifically to the triad of PDD impairments (or social and communication difficulties in ADHD were due specifically to core ADHD features)
ADHD always occurred with PDD (or visa versa)
Inattention and hyperactivity/impulsivity in PDD differed qualitatively from ADHD as defined by DSM-IV-TR OR
Social and communication difficulties in ADHD differed qualitatively from PDD as defined by the DSM-IV-TR

45. Discussion:
Based on your different experiences with kids with ADHD/PDD, how would you like to see the DSM-V approach these two disorders?

46. Questions?