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Attention Deficit Hyperactivity
Disorder
James H. Johnson, Ph.D., ABPP
University of Florida
ADHD: Nature of the Problem
ADHD is a neurodevelopmental
disorder of childhood
 Characterized by developmentally
inappropriate levels of:
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– Hyperactivity,
– Impulsivity,
– Inattention.
ADHD: How Common is it?
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Prevalence is estimated at 3 to 9 per cent
of the elementary school population.
ADHD occurs more often in males than
females, with the sex ratio being about 4
to 1.
One of the most common disorders of
childhood
Accounts for a large number of referrals
to pediatricians, family physicians and
child mental health professionals.
ADHD: Not a New Problem
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Characteristics of this disorder have been
recognized for at least a century
Still (1902): ADHD Case study
Fidgety Phil
(http://www.fln.vcu.edu/struwwel/philipp_e.html
Has been referred to by a variety of labels;
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Minimal Brain Dysfunction (MBD)
Hyperkinetic Reaction of Childhood
Attention Deficit Disorder (ADD)
Attention Deficit Hyperactivity Disorder
(ADHD)
Some Highlights in the Evolution of
the Disorder
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Encephalitis epidemic of 1917 - 1918
Frontal lobe ablation studies with
primates (1930’s)
Strauss’ work on Minimal Brain
Dysfunction (1940's -1950's)
Beginnings of child psychopharmacology;
Using Amphetamines for treatment –
1930-1940.
MBD becomes Hyperkinetic Disorder (the
1960’s)
Evolution of the Disorder (cont.)
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The focus on attention – The 1970’s
Focus on the Feingold diet
Studies of psychophysiological
responsivity
Development of objective diagnostic
criteria: DSM III- and ADD (the early
1980’s)
The 1990’s - Present:
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Imaging,
Genetics,
DSM IV
Focus on Evidence Based Methods.
ADHD: Core Features
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As noted earlier, ADHD is a disorder
characterized by developmentally
inappropriate levels of :
Symptoms of Hyperactivity
DSM IV Symptoms of
Hyperactivity/Impulsivity
Fidgets with hands or feet, squirms
in seat.
 Leaves seat in classroom or in other
situations in which remaining
seated is expected
 Runs about or climbs excessively in
situations where not appropriate.
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More Symptoms of Hyperactive
Has difficulty playing or engaging in
leisure activities quietly.
 Often "on the go" or often acts as if
"driven by a motor“.
 Talks excessively when
inappropriate to the situation
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Symptoms of Impulsivity
Symptoms of Impulsivity
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Blurts out answers before questions
have been completed.
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Has difficulty awaiting turn.
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Interrupts or intrudes on others.
Six symptoms of hyperactivity and
impulsivity (combined) are required
for diagnosis.
What do we Know about
Hyperactivity?
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Children with ADHD are more active,
restless, and fidgety than normal
children during the day and during
sleep.
Different types of hyperactivity.
– Gross Motor Activity
– Restless/Squirmy
– Occasionally see verbal hyperactivity
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Hyperactivity often varies according to
situation
Level of stimulation
Symptoms of Inattention
Symptoms of Inattention
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Fails to give close attention to details
or makes careless mistakes.
Has difficulties sustaining attention in
tasks or play activities.
Does not seem to listen when spoken
to directly.
Does not follow through on
instructions and fails to finish
homework, chores, or duties in the
workplace
More Symptoms of Inattention
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Has difficulty organizing tasks and
activities
Avoids, dislikes, or is reluctant to engage
in tasks that require sustained mental
effort.
Loses things necessary for tasks or
activities
Easily distracted by extraneous stimuli.
Forgetful in daily activities
(Six or more symptoms of inattention necessary for
diagnosis)
What Do We Know About ADHD
Attention Problems?
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ADHD "attention" problems may be most
obvious on specific types of tasks.
Children with ADHD have their greatest
difficulties with sustaining their attention
in responding to tasks - in being vigilant.
Problems are usually seen in situations
requiring the child to attend over time to
rather dull, boring, and repetitive tasks.
Situational Variations in Symptoms
Symptoms can show significant
variation across situations.
 Children do not display symptoms
in all situations
 The absence of symptoms in some
situations (e.g. video games) does
not mean that the child does not
have ADHD.
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Situations That Increase ADHD
Symptoms
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The greater the demands of the situation, the
more problematic the behavior will likely become.
An exception might be in situations where the
child is being continuously rewarded for
complying with demands.
In familiar situations where novelty and task
stimulation are low.
When Fatigued
– Studies, monitoring 24 hour activity levels have
suggested that the hours of 1 – 5 seem to be peak times
for increased activity in children with ADHD.
Overview of Diagnostic Criteria
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Symptom Criteria - Core Symptoms of
Hyperactivity & Impulsivity and/or Inattention
(Six or More Symptoms of either category).
Duration Criterion - Symptoms have Persisted for
at Least 6 Months.
Developmental Criterion - Symptoms are
Inconsistent with Developmental Level (MR).
Impairment Criterion - Clear Evidence of
Clinically Significant Impairment in Social,
Academic, or Occupational Functioning
Overview of Criteria (cont.)
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Age Criterion - Some Symptoms that Cause
Impairment Were Present Before Age 7.
Situation Criterion - Some Impairment from
Symptoms is Present in Two or More Settings.
NOTE. The failure to attend to full range of
symptoms is not uncommon
Presence of hyperactivity, impulsivity, and
inattentive symptoms is not necessarily to be
equated with ADHD.
Types of ADHD
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Combined Type
– Symptoms of hyperactivity, impulsivity and
inattention.
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Hyperactive/Impulsive (Does it really exist?)
– Symptoms of hyperactivity and impulsivity.
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Predominately Inattentive
– Symptoms of inattention.
ADHD Mimicry
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Sensory Impairments
Medication side effects
– Phenobarbital
– Dilantin
– Some Asthma Medications
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Seizure Disorder
RTH (Resistance to Thyroid Hormone)
PTSD
Bipolar Disorder
Anxiety Disorders
Depressive Disorders
Auditory Processing Disorder
Why is Mimicry of Clinical Significance???
Comorbid Conditions
What are comorbid conditions?
 Controversy over use of the term.
 Why is it essential to consider the possibility of
comorbid conditions in assessing children with
ADHD?
 Importance of distinguishing between comorbid
conditions and mimicry.
 What is the frequency of comorbidities in
children with ADHD?
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Comorbid Conditions
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Learning Disabilities ~ 19 to 26%
Oppositional Defiant Disorder ~ 40% Conduct Disorder
~ 25% children; ~ 45-50% Adolescents.
Anxiety Disorders ~ 30%
Depressive Disorder ~ 10 - 30%
Bipolar Disorder – up to 20%.
Tics and Tourette’s Disorder ~ 7% of children with
ADHD have a tic disorder.
~ 40 to 50% of those with Tourette’s disorder have
ADHD
Developmental Issues
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There are factors in infancy (e.g., difficult
temperament) that seem to be precursors of ADHD.
Initial development of ADHD is most often during the
preschool years.
While there is often a decline in the level of
hyperactivity and perhaps some improvement in
attention and impulse control in adolescence, as many
as 70 % continue to be impaired by their symptoms
and meet criteria for some type of ADHD.
A significant number of children with ADHD
(probably over 50%) continue to display problems
into the adult years.
Prognosis of ADHD
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Outcome of ADHD in adolescents is highlighted by
the results of a study by Barkley, Fischer, et al,
(1990).
Study followed a large sample of children with
ADHD (158) and normal children (81) prospectively
for 8 years after diagnosis.
123 hyperactive children and 66 normals were
located, interviewed and complete questionnaires.
In the hyperactive group 12 (9.7%) were female and
111 were male. In the normal group 4 of the subjects
were female and 62 were male.
Prognosis In Adolescence
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The majority of the hyperactive subjects
(71.5%) met DSM III-R criteria for ADHD at
follow up [Biederman (2000) found ~ 70%].
– Note DSM III – R criteria change
More than 59% met criteria for Oppositional
Defiant Disorder as compared to 11% of the
controls.
 Approximately 43 % of the hyperactive group
could be diagnosed as CD as compared to 1.6%
of the control group.
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What About Driving ?
Hyperactive subjects were more likely to have
had an auto accident, to have had more
automobile accidents, to have had more bodily
injuries in accidents, and to be at fault for
accidents more often than did controls.
 Adolescents in the hyperactive group were also
more likely to have received traffic citations,
especially for speeding
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How About Substance Use ?
Cigarette and alcohol use were the only
categories of substance use that differentiated
those with hyperactivity from normals.
 When the the hyperactive sample was separated
into groups (purely ADHD and ADHD + CD)
purely ADHD subjects showed no greater use of
cigarettes, alcohol, or marijuana than did normal
controls.
 Mixed hyperactive/Conduct disordered children
displayed two to five times the rate of substance
use as did pure hyperactives or normals.
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What About School Performance?
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Three times as many hyperactives had failed a grade
(29.3% versus 10%), had been suspended (46.3%
versus 15.2%) or had been expelled (10.6% versus
1.5%).
Results indicated that hyperactivity alone increases the
risk of suspension (30.6% vs 15.2%), and dropping out
(4.8% vs 0% ) as compared to controls
However, the added diagnosis of CD greatly increases
the risk (67% suspended, 13% dropped out).
The presence of CD accounted almost entirely for the >
risk of expulsion within the hyperactive group
Prognosis In Adulthood
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Studies have suggested that anywhere between 4 and 60 % of
children diagnosed with ADHD will display symptoms in
adulthood serious enough to interfere with academic, vocational
or social functioning.
Variability in results likely relates to different criteria used for
diagnosis of ADHD in adults.
There are indications that the type of ADHD that persists into
adulthood is more highly genetic than the type that remits in
childhood.
ADHD in adults is sometimes considered a “hidden disorder”
as symptoms are often obscured by other problems.
Prevalence is thought to be 2 – 4% with sex ratio of 2 – 1 or
lower).
Etiology
Etiology:ADHD Risk Factors
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Maternal cigarette use
Maternal alcohol use
Maternal drug use
A variety of factors that can be related to
fetal distress
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Unusually long or short labor
Forceps delivery
Toxemia
Meconium staining
Nuchal cord
Birth during the month of September.
Minor physical anomalies
Etiology - Genetics
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Between 10 and 35 per-cent of the
immediate family members of children
with ADHD also display this disorder.
Risk for siblings of children with ADHD
is approximately 32%
If a parent has ADHD the risk to
offspring is on the order of 50+%
Twin studies suggest concordance rates
for monozygotic twins is around 80%
with concordance rates of 30% for dz
twins.
Etiology - Genetics
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Overall, twin studies suggest an average
heritability of .80
Work in the area of molecular genetics has also
identified specific genes related to ADHD.
Molecular genetics has begun to identify
specific genes related to ADHD
These genes have to do with the transport of
and post-synaptic sensitivity to the
neurotransmitter dopamine in the frontal lobes.
Hereditary is one of the most well supported
etiological factors in the development of ADHD
Etiology – Neurological Insult
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Multiple factors that can result in brain
damage are associated with ADHD.
For example, anoxia, is associated with
increased frequencies of hyperactivity and
attention problems.
ADHD occurs more often in children with
seizure disorders, who are presumed to
have neurological involvement
As noted earlier, diseases like encephalitis
can also result in symptoms of ADHD, as
can various types of infections and
injuries.
Etiology: Brain Damage
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These findings suggest that neurological insult
can result in an increased probability of
developing ADHD.
However, most children with ADHD do not have
a significant history of brain injury.
Such injuries are unlikely to account for ADHD
in the vast majority of children.
In fact probably 95% of hyperactive children
show no evidence of documentable neurological
impairment.
This does not mean, however, that
neurodevelopmental factors are not involved.
Neuropsychological Test Findings:
Executive functioning deficits
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Results from research involving
neuropsychological testing has often suggested
that children with ADHD have problems;
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in inhibiting behavioral responses,
in initiating behavior
in shifting from one activity to another
with working memory,
with planning and organization,
with perseveration,
in motor sequencing,
with other frontal lobe functions.
Executive Functioning Deficits
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Not only do children with ADHD show
executive functioning deficits but siblings
of ADHD children who do not have ADHD,
have been shown to display milder yet
significant impairments of the same type.
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This suggests a possible genetic risk for
executive function deficits in families.
Studies of Brain Function
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Studies of cerebral blood flow in ADHD
and normal children have consistently
shown decreased blood flow to the
prefrontal regions and pathways
connecting these regions to the limbic
system via the striatum
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Studies using PET scans to assess
cerebral glucose metabolism in the
frontal regions have found diminished
metabolism in, adults and adolescent
females with ADHD (e.g. decreased activity).
Cerebral Blood Flow (cont)
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A significant correlation between
diminished metabolic activity in the left
anterior frontal region and severity of
symptoms in adolescents with ADHD has
also been demonstrated.
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This demonstration of a relationship
between decreased metabolic activity and
the symptom severity is crucial to
specifically documenting the importance
of the link between lower levels of brain
activation and ADHD-related behavior.
Frontal Lobes
Basal Ganglia
MRI Studies
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Some, but not all studies have found the
Corpus Callosum, to be smaller in children
with ADHD.
Other MRI studies have found children
with ADHD to have a smaller left caudate
nucleus.
These findings are interesting in light of
the results of prior blood flow studies
suggesting lower levels of activation in
this area in children with ADHD.
MRI Continued
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Several more recent MRI studies, with
larger samples, have suggested that
children with ADHD have significantly
smaller anterior right frontal regions, a
smaller caudate nucleus, and smaller
globus pallidus regions than normals.
Research has also found decreased
cerebellar volume in children with
ADHD.
Work in this area suggests that
abnormalities in the development of the
frontal-striatal regions may well
underlie the development of ADHD.
Neurotransmitter Deficiencies
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The possibility of a neurotransmitter
dysfunction in children with ADHD has
been suggested for many years.
This notion seemed to originate from the
fact that children with ADHD respond to
different types of stimulant drugs.
The fact that stimulant drugs have an
impact on ADHD and that they increase
dopamine has contributed to the
neurotransmitter dysfunction
hypothesis.
Other neurotransmitters are also likely to
be involved
Neurotransmitter Deficiencies
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There is more direct evidence of
neurotransmitter deficiencies from some
studies of cerebral spinal fluid in children
with and without ADHD, which suggests
decreased dopamine levels in children with
ADHD
There is also some evidence of a
deficiency in the availability of
norepinephrine in children with ADHD.
This is of interest given that a relatively
new non-stimulant ADHD medication,
Straterra, is thought to act on
norepinephrine levels.
Etiology: Psychosocial Factors
There is little evidence for the role of
psychosocial factors in the
development of ADHD, although
factors such as parent-child conflict
may exacerbate problems in a child
with ADHD.
 Psychosocial factors may also
contribute significantly to the
development of certain comorbid
disorders that may complicate the
clinical picture.
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Etiology: Overview
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In reviewing the literature on the
etiology of ADHD, Barkley suggests …
– “It should be evident from the research…that
neurological and genetic factors make a
substantial contribution to symptoms of
ADHD and the occurrence of this disorder.
– A variety of genetic and neurological
etiologies (e.g., pregnancy and birth
complications, acquired brain damage,
toxins, infections, and genetic effects) can
give rise to the disorder through some
disturbance in a final common pathway in
the nervous system.
Overview Continued
That final common pathway appears to be the
integrity of the prefrontal cortical-striatal
network.
 It now appears that hereditary factors play the
largest role in the occurrence of ADHD
symptoms in children.
 It may be that what is transmitted genetically is
a tendency toward a smaller and less active
prefrontal-striatal network.
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Overview Continued
The condition can also be caused or
exacerbated by pregnancy
complications, exposure to toxins, or
neurological disease
 Cases of ADHD can arise without
genetic predisposition if the child is
exposed to a significant disruption or
neurological injury to this final
common neurological pathway.
 This would seem to account for only
a small minority of ADHD children. “
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Why Should We Treat ADHD ?
Treatment of ADHD
Stimulant Medications
 Other Medications
 Psychosocial Treatments
 Educational Accommodations
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Commonly Used Stimulant
Medications
Ritalin
 Dexadrine
 Adderall
 Concerta
Between 70 and 80 % of children with ADHD respond
positively to stimulant drugs.
Stimulant drugs represent an empirically supported
treatment for core symptoms of ADHD.
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Approved Medication For ADHD
Side Effects of Stimulants
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Common side effects can include: loss of
appetite, weight loss, sleeping problems,
irritability,
restlessness, stomachache, headache, rapid
heart rate, elevated blood pressure, sudden
deterioration of behavior
symptoms of depression with sadness,
crying, and withdrawn behavior.
intensification of tics (muscle twitches of
the face and other parts of the body),
possible Tourette’s and growth suppression.
Side Effects (Cont.)
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While side effects are always a possibility
they are often
– Transient in nature
– The result of inappropriate medication levels
If one medication results in side effects,
another might be used without side effects.
 Sometimes other medications are used to
minimize side effects.
 Good clinical judgment by the clinician may
help to minimize side effects.
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Some Examples of NonStimulant Drugs
in ADHD Treatment
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Non Stimulant ADHD Medication
– Straterra - a norepinephrine reuptake inhibitor- selectively
blocks the reuptake of norepinephrine, which increases its
availability
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Other Non Stimulant Drugs
– Anti-depressants (e.g., Tofranil, Wellbutrin)
– Anti-hypertensives (Clonidine)
Psychosocial Treatments
Parent Training
 Social Skills Training
 Cognitive Behavioral Treatments.
 Psychotherapy for comorbid conditions
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Educational Interventions
Special Education Services for existing
learning problems.
 Classroom accommodations.
 Classroom behavior modification programs.
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Treatment: Concluding Comments
In treating ADHD it is essential to treat the
full range of difficulties that impact on child
and family functioning.
 Treatment of ADDH will often need to be
“multimodal” in nature.
 Findings from the Multimodal Treatment
Study suggest that;
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– Stimulant medication is effective in reducing core
symptoms
– Psychosocial treatments are of value in
addressing associated comorbidities.
That’s All Folks!