THE MANY FACES OF ADHD
Francis M. Crinella, Ph.D.
Clinical Professor of Pediatrics, Psychiatry & Human Behavior,
and Physical Medicine & Rehabilitation
Director, Neuropsychology Laboratory
Child Development Center
University of California, Irvine
25 JAN 10
WHAT IS ATTENTION?
A special [mental] function was instituted which
had periodically to search the outer world in order
that its data might be already familiar if an urgent
inner need should arise: This function was
attention. Its activity meets the sense
impressions half way, instead of awaiting their
appearance. At the same time, there was
probably introduced a system of notation, whose
task was to deposit the result of this periodic
activity of consciousness—a part of which we call
memory.
Sigmund Freud [Formulations regarding the two
principles of mental functioning, 1911]
WHAT IS ATTENTION?
Everyone knows what attention is. It is
the taking possession in the mind, in clear
and vivid form, of one out of what seem
several simultaneous object or trains of
thought.
William James [The Principles of
Psychology, 1890]
CONSIDER YOUR LIFE
WITHOUT ATTENTION-SOME IMPORTANT
FEATURES OF ATTENTION
ATTENTION HELPS US TO MANAGE
CONFLICTING PERCEPTUAL INPUTS
ATTENTION ALLOWS US TO
PERSIST IN TASK PERFORMANCE
ATTENTION HELPS US FOCUS ON
THE TASK AT HAND
ATTENTION ENABLES US TO PERFORM
TASKS THAT REQUIRE PLANNING AND
WORKING MEMORY
ATTENTION ENABLES US TO MAINTAIN
VIGILANCE WHEN MONITORING SIGNALS
ATTENTION ENABLES US TO
AVOID COSTLY ERRORS
HOWEVER: ATTENTION ITSELF
IS ONE OF THE MOST FRAGILE
OF ALL MENTAL FUNCTIONS
•IT CAN BE ADVERSELY AFFECTED BY ANY NUMBER OF
INFLUENCES
•ALMOST EVERY NEUROPSYCHIATRIC DISORDER IS
ACCOMPANIED BY SOME KINDS OF ATTENTION DEFICITS
•ADHD IS BUT ONE OF THE PSYCHIATRIC DISORDERS IN
WHICH ATTENTION IF AFFECTED
• ADHD MAY AFFECT SEVERAL DIFFERENT
COMBINATIONS OF ATTENTIONAL COMPONENTS
DSM-IV SYMPTOMS OF ADHD
INATTENTION
• CAN’T ATTEND TO
•
•
•
•
•
•
•
•
DETAILS
CAN’T SUSTAIN
ATTENTION
DOESN’T LISTEN
FAILS TO FINISH
CAN’T ORGANIZE
TASKS
AVOIDS SCHOOLWORK
LOSES THINGS
EASILY DISTRACTED
FORGETFUL
HYPERACTIVITY/IMPULSIVITY
•
•
•
•
•
•
•
•
•
FIDGETS
CAN’T STAY SEATED
RUN ABOUT AND CLIMBS
CAN’T PLAY QUIETLY
IS OFTEN ON THE GO
TALKS TOO MUCH
BLURTS OUT ANSWERS
CAN’T WAIT TURN
INTERRUPTS OR INTRUDES
CONFIGURATION OF DSM-IV SYMPTOMS OF ADHD
IN PATIENT #1
INATTENTION
HYPERACTIVITY
/IMPULSIVITY
1
CAN’T ATTEND
TO DETAILS
YES
FIDGETS
YES
2
CAN’T SUSTAIN
ATTENTION
NO
CAN’T STAY
SEATED
YES
3
DOESN’T LISTEN
NO
RUN ABOUT AND
CLIMBS
YES
4
FAILS TO FINISH
YES
CAN’T PLAY
QUIETLY
YES
5
CAN’T
ORGANIZE
TASKS
YES
IS OFTEN ON
THE GO
YES
6
AVOIDS
SCHOOLWORK
NO
TALKS TOO
MUCH
NO
7
LOSES THINGS
EASILY
NO
BLURTS OUT
ANSWERS
NO
8
DISTRACTED
NO
CAN’T WAIT
TURN
YES
9
FORGETFUL
YES
INTERRUPTS OR
INTRUDES
YES
NUMBER OF
INATTENTION
SYMPTOMS
4
NUMBER OF
HYPERACTIVITY
SYMPTOMS
7
SYMPTOM CHECKLISTS FOR TWO PATIENTS WHO
MEET CRITERIA FOR ADHD,
HYPERACTIVE/IMPULSIVE SUBTYPE
HYPERACTIVITY/
IMPULSIVITY
PATIENT #1
PATIENT #2
1
FIDGETS
YES
NO
2
CAN’T STAY SEATED
YES
NO
3
RUNS ABOUT AND CLIMBS
YES
NO
4
CAN’T PLAY QUIETLY
YES
YES
5
IS OFTEN ON THE GO
YES
YES
6
TALKS TOO MUCH
YES
YES
7
BLURTS OUT ANSWERS
NO
YES
8
CAN’T WAIT TURN
NO
YES
9
INTERRUPTS OR INTRUDES
NO
YES
6
6
TOTAL”YES”
NUMBER OF POSSIBLE OF DSM-IV
SYMPTOM CONFIGURATIONS THAT
MEET CRITERIA FOR DIAGNOSIS OF
ADHD
FOR HYPERACTIVE SUBTYPE ONLY:
– NUMBER OF VARIATIONS ON 9 CRITERIA
9/6 = 84
9/7 = 36
9/8 = 9
9/9 = 1
∑
=
130
NUMBER OF POSSIBLE OF DSM-IV
SYMPTOM CONFIGURATIONS THAT
MEET CRITERIA FOR DIAGNOSIS OF
ADHD—ALL SUBTYPES
HYPERACTIVE SUBTYPE: 130
INATTENTIVE SUBTYPE: 130
COMBINED SUBTYPE: 260
SUM OF POSSIBLE CONFIGURATIONS: 520
DOMAIN OF ADHD SYMPTOMS
7
8
2
1
13
12
4
14
18
3
9
5
6
11
16
17
10
15
ADHD SYMPTOMS AS SUBDOMAIN OF MORE
INCLUSIVE DOMAIN OF ALL SYMPTOMS OF
NEUROPSYCHIATRIC DISORDER
1
3
8
2
7
11
10
12
13 14
9
4
17
18 5
15
16
6
INDIVIDUAL WITH “PURE”ADHD, REPRESENTED AS SUBSET OF
SYMPTOMS IN ADHD SUB-DOMAIN, EXCLUSIVE OF ALL NONADHD SYMPTOMS IN LARGER DOMAIN OF ALL MALADAPTIVE
BEHAVIORS
1
3
4
2
6
8
7
11
10
12
13 14
18 5 9
17
16 15
MORE COMMON CASE: INDIVIDUAL WHO MEETS DSMIV DIAGNOSTIC CRITERIA FOR ADHD, BUT ALSO
PRESENTS WITH SYMPTOMS NOT CONSIDERED
DIAGNOSTIC OF ADHD
1
2
7
3
4 6
18
5
11
8 10 12
13 14
9 17
16 15
IS THIS ADHD? INDIVIDUAL STILL MEETS DSM-IV DIAGNOSTIC
CRITERIA FOR ADHD, BUT ALSO PRESENTS WITH MANY MORE
SYMPTOMS NOT CONSIDERED DIAGNOSTIC CRITERIA FOR
ADHD
1
3
4
2
6
18
8
7
5
16 15
11
10
13
12
14
9 17
PROBLEM: MANY CONFIGURATIONS OF
MALADAPTIVE BEHAVIOR ARE LABELED
“ADHD”
•Should the label, ADHD, be assigned to a
potpourri of disorders with only some
features in common?
•Are there “core” features of “true” ADHD?
•What are the most common non-core
accompaniments of ADHD?
•When do these non-core features signify
that a diagnosis other than ADHD is more
appropriate?
BIOLOGICAL EVIDENCE FOR A
CORE ADHD SYNDROME
1. NEUROCHEMICAL
2. GENETIC
3. ELECTROPHYSIOLOGICAL
4. FUNCTIONAL IMAGING
5. NEUROPSYCHOLOGICAL
NEUROCHEMICAL
MOST EFFECTIVE TREATMENT--CNS
STIMULANTS
• DEXTROAMPHETAMINES
• METHYLPHENIDATES
• EFFECTS:
–
–
–
–
–
Improved classroom behavior
Improved academic productivity
Improved peer/adult interactions
Less frequent oppositional conduct
Reduced aggression
GENETIC
 BEFORE MOLECULAR BIOLOGY
 Catecholamine hypothesis—genetic variations in
brain neurochemistry (Wender, 1971)
 Family genetic studies (e.g., Faroane, Biederman,
Chen et al., 1992)
 AFTER MOLECULAR BIOLOGY
 Subsensitive dopamine receptor hypothesis; DRD4
gene (LaHoste, Swanson, Wigal, et al., 1996)
 Dopamine transporter gene (Cook, Stein,
Krasowski, et al., 1995)
FUNCTIONAL BRAIN IMAGING

Evidence before modern imaging methods



MBD hypothesis (Clements et al, 1963)
Neuropsychology of MBD (Crinella, 1972)
Evidence from modern imaging methods



Methods used: PET; SPECT; fMRI
Results: Variations in size and symmetry of
brain structures (e.g., Swanson & Castellanos,
1997)
Structures involved:
FRONTO-STRIATAL NETWORK
CAUDATE NUCLEUS
BASAL GANGLIA
RECENT BRAIN IMAGING STUDIES IN
ADHD
9
8
7
6
5
4
3
2
1
0
Caudate
DL Frontal
Putamen-gp
Occipital
Temporal
Insula
A. Cingulate
Premotor
Thalamus
Hippocampus
Insula
CC (genu)
CC (splenium)
Periventricular
Premotor
basal gangial
ELECTROPHYSIOLOGY
Early studies of analog EEG
Satterfield, J.H., & Schell, A.M. (1984). Childhood brain
function differences in delinquent and non-delinquent
hyperactive boys. Electroencephalography and Clinical
Neurophysiology, 57, 199-207.
Finding: Abnormal maturational effects of auditory eventrelated potential differentiated ADHD from non-ADHD subjects
Recent brain mapping studies
Pliszka, S.R., Liotti, M., & Woldorff, M.G. (2000). Inhibitory
control in children with attention-deficit/hyperactivity disorder.
Biological Psychiatry, 48,238-46.
Finding: Event related potentials identify the processing
component and timing of an impaired right-frontal responseinhibition mechanism.
COGNITIVE NEUROPSYCHOLOGY
BASED ON TRADITIONAL APPROACH TO
STUDYING BRAIN-BEHAVIOR RELATIONSHIPS
1. Experimental removal of brain structures
2. Observation of effect on specific behavioral
functions
3. Identification of brain structures/networks
that are correlated with ADHD-like behavior
DISTINCT ANATOMICAL NETWORKS CARRY
OUT SPECIFIC ASPECTS OF ATTENTION
• ALERTING NETWORK
– LOCATION: ARAS, ETC.
– FUNCTION: ACHIEVE AND MAINTAIN STATE OF READINESS
• ORIENTING NETWORK
– LOCATIONS: PARIETAL LOBE, SUPERIOR COLLICULUS &
PULVINAR
– FUNCTION: REACT TO SENSORY STIMULI
• EXECUTIVE NETWORK
– LOCATION: ANTERIOR CINGULATE; DORSOLATERAL FRONTAL
CORTEX & BASAL GANGLIA
– FUNCTIONS:
• CONTROL NEURAL RESPONSES TO STIMULI
• GENERATE NEW INFORMATION FROM LONG TERM MEMORY
• PRIORITIZE OPERATION OF OTHER BRAIN AREAS
ADHD IS A DISORDER THAT
PRIMARILY AFFECTS THE
EXECUTIVE NETWORK
SOME FEATURES OF
EXECUTIVE FUNCTION—
STERNBERG (1985)
• Decision as to just what the problem is
•
•
•
•
•
that needs to be solved
Selection of lower-order components
Selection of one or more representations
of organizations for information
Selection of a strategy for combining
lower order components
Decision regarding tradeoffs in the speed
and accuracies with which various
components are executed
Solution monitoring
TESTS OF EXECUTIVE FUNCTION IN
THE HUMAN NEUROPSYCHOLOGY
LABORATORY
• By definition, no test can be performed in the
absence of executive control
• Executive functions must be differentiated from
other cognitive
– abstract reasoning
– crystallized problem solving
– long term memory
– sensory-perceptual processing
– motor control systems
– Motivational states
• Which tests do this best?
SPECIFIC NEUROPSYCHOLOGICAL
APPROACHES TO IDENTIFICATION OF
ADHD
EXAMPLE OF LABORATORY MEASURE OF
EXECUTIVE FUNCTION--CONTINUOUS
PERFORMANCE TEST (CPT)
– FOCUSES ON SPECIFIC AREAS OF EXECUTIVE
FUNCTION
• TASK PERSISTENCE
• VIGILANCE
• IMPULSE CONTROL
• REGULATION OF AROUSAL LEVEL
A
PRESS BUTTON EVERY TIME A LETTER APPEARS
X
EXCEPT WHEN THE LETTER “X” APPEARS
CONTINUOUS PERFORMANCE TEST
SCORING CATEGORIES:
• Omissions
• Commissions
• Overall Processing Speed
• Overall Attentional Variability
• Perceptual Sensitivity
• Risk Taking
• Perseverations
• Speed Decrement Over time
• Variability Over time
• Activation/arousal
HIT REACTION TIME
700
675
650
4 SEC
MILLISECONDS
625
600
2 SEC
575
550
525
500
475
450
425
400
375
350
325
300
1 SEC
TYPICAL
ADHD
STANDARD ERROR OF HIT REACTION TIME
100
4 SEC
90
MILLISECONDS
80
2 SEC
70
1 SEC
60
50
40
30
20
10
0
TYPICAL
ADHD
COMMISSION ERRORS
1.8
1.6
MILLISECONDS
1.4
1.2
1
CONTROLS
ADHD
0.8
0.6
1 SEC
0.4
0.2
0
2 SEC
4 SEC
NON-ADHD CONDITIONS THAT CAN
AFFECT SCORES ON CPT:
• Commissions: anxiety; toxic irritability
• Omissions: depression; dyspraxia; schizophrenia
• Overall Processing Speed: depression; anxiety;
metabolic conditions (e.g., hypoglycemia)
• Perceptual Sensitivity: Visual acuity; dyseidetic
dyslexia; cataracts;
• Risk Taking: psychopathy; anxiety; bipolar disorder
• Perseverations: psychomotor retardation; frontal
lobe damage; frank mental retardation
• Speed Decrement Over time: depression; diabetes;
hypothyroidism
• Activation/arousal: schizotypal conditions
(blocking); obsessional states; malnutrition
CPT AND DSM-IV COMMONALITIES FOR INDIVIDUALS WITH
ADHD AND INDIVIDUALS WITH ANXIETY
CPT
UNDERAROUSED
IMPERSISTENT
IMPULSIVE
RECKLESS
PERSEVERATIVE
DSM-IV
RESTLESS AND ON EDGE
DIFFICULTY CONCENTRATING
IRRITABLE
TENSE
DISTURBED SLEEP
CPT AND DSM-IV COMMONALITIES FORINDIVIDUALS WITH ADHD AND
INDIVDUALS WITH DEPRESSION
CPT
IMPULSIVE
IMPERSISTENT
UNDERAROUSED
RECKLESS
PERSEVERATIVE
DSM-IV
LOW ENERGY OR FATIGUE
POOR CONCENTRATION
INSOMNIA/HYPERSOMNIA
HOPELESSNESS
POOR APPETITE
CONCLUSIONS REGARDING THE
DIAGNOSTIC SPECIFICITY OF TESTS OF
EXECUTIVE FUNCTION
The capacity to maintain attention is fragile,
and may be affected by virtually any
psychiatric and/or neurological condition
Even on tests of executive function, thought
to be quite specific for the “core” deficits
found in ADHD, problems other than ADHD
will affect performance
CONCLUSIONS
Many individuals thought to have ADHD may have
behavioral deficits that are commonly found
among individuals with ADHD, but these deficits
are also found in individuals with a host of other
psychiatric disorders
The incidence and prevalence of persons who have
true ADHD, a hereditarily-transmitted disorder of
the brain’s dopaminergic networks is probably
much less than claimed by ADHD professionals
and advocates
Nevertheless: Those whose attentional processes
are affected by neuropsychiatric conditions other
than ADHD are as deserving of treatment and
accommodations for their attentional deficits as
are those with “true” ADHD