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Understanding and Treating ADHD 1
Running head: UNDERSTANDING AND TREATING ADHD
Chapter 39 Understanding and Treating ADHD
Nancy A. Neef
Christopher J. Perrin
The Ohio State University
Key Terms: ADHD, functional definition, delay-of-reinforcement, inattentiveness, hyperactivity,
impulsivity
Understanding and Treating ADHD 2
Attention deficit/hyperactivity disorder (ADHD) is one of the most frequent diagnoses
among school age populations. Recent studies estimate the prevalence at approximately 7% of
children ages 3-17 years in the United States (Center for Disease Control and Prevention, 2005).
Boys are twice as likely to be diagnosed with ADHD as girls (Bloom & Cohen, 2007). Data
suggest that children who are of poor or fair health status are three times more likely to be
diagnosed with ADHD than children with better health (Bloom & Cohen, 2007). ADHD is
associated with several comorbid disorders; the most common are oppositional defiant disorder
(estimated in 40% to 65% of individuals with ADHD) and learning disabilities (approximately
31% of individuals with ADHD) (DuPaul & Stoner, 1994).
Although the prevalence of ADHD is of itself reason for concern, a number of poor
outcomes also have been correlated with childhood diagnoses of ADHD. For instance, 12-year-
old-children diagnosed with ADHD were found to have significantly lower reading achievement
scores, higher rates of absenteeism, increased occurrence of grade retention, and greater
incidence of dropping out of school than those without the diagnosis (Barbaresi, Katusic,
Colligan, Weaver, & Jacobson, 2007). Children with ADHD are more likely to have social
difficulties that interfere with friendships, family interactions, leisure activities, and occupational
performance than peers without ADHD (Mannuzza, Klein, Bessler, Malloy, & Hynes, 1997;
Strine et al., 2006). Furthermore, children with disabilities including ADHD have been linked
with a higher prevalence of nonfatal injuries (Schubiner et al., 2000; Xiang, Stallones, Chen,
Hostetler, & Keller, 2005) as well as higher rates of substance abuse (Levin & Kleber, 1995).
Collectively, these statistics suggest that early diagnosis and intervention for children with
ADHD is paramount in improving their quality of life.
DIAGNOSIS AND ASSESSMENT
Understanding and Treating ADHD 3
The Diagnostic and Statistical Manual IV (DSM-IV) describes ADHD as “a persistent
pattern of inattention and/or hyperactivity-impulsivity that is more frequently displayed and
more severe than is typically observed in individuals at a comparable level of development.”
(American Psychiatric Association, 2000, p.85). ADHD is divided into three subtypes:
predominantly inattentive type, predominantly hyperactive-impulsive type, and combined type.
Diagnosis and classification into one of these subtypes is usually made by matching observed
behaviors to symptoms listed as diagnostic criteria in the DSM-IV. Because the symptoms of
ADHD occur periodically in most people, the symptoms must have been present for at least six
months and occur at a level that is both disruptive and developmentally inappropriate.
Structural Approaches
The process of diagnosing ADHD using DSM-IV criteria is a topographical assessment.
That is, diagnosis is made based upon what an individual’s behavior looks like (i.e., its
topography). Unfortunately, there is no commonly accepted measure for diagnosing ADHD.
Diagnosis is usually based on indirect measures such as behavior rating scales, which have a
number of shortcomings. The descriptors typically do not have objective anchors, are not
operationally defined, and involve subjective judgments subject to informant bias, often resulting
in inconsistent and imprecise application (Atkins & Pelham, 1991; Gulley & Northup, 1997;
Kollins, Ehrhardt, & Poling, 2000, Stoner, Carey, Ikeda, & Shinn, 1994). Virtually all widely
used neuropsychological tests for assessing ADHD have low predictive validity when used at the
level of individual assessment (Barkley, 2008).
Another limitation of a topographical assessment is that it does not provide information
as to the purpose or functional properties of behaviors of concern, and therefore it has limited
utility in guiding treatment. Although many behaviors look alike, it is quite possible and often
the case that they occur for different reasons. For example, one child might scoot in his chair to
within kicking distance of the girl seated in front of him. The girl might scoot her chair forward
Understanding and Treating ADHD 4
in the same manner, out of kicking distance of the boy behind her. The chair scooting of both
children might look the same, but they serve different purposes (gaining the attention of the girl
versus escaping the chair kicks of the boy). An alternative seating arrangement would eliminate
the need for the girl to scoot her chair, but it would likely result in the boy engaging in other
inappropriate bids for the girl’s attention (e.g., throwing paper wads at her). Interventions for
problem behavior that are based on a behavior’s form without considering its function often fail,
thus increasing reliance on more intrusive interventions such as punishment.
Functional Approaches
An alternative approach to using topographical descriptions is to define behavior
according to its function (see Chapter X). There are several advantages to this approach. From a
diagnostic standpoint, it is likely that a functional definition of a disability such as ADHD is
more precise, resulting in a more homogenous group and better prediction of treatment effects.
Importantly, identifying the function of a behavior informs treatment. That is, when the function
of the behavior is known, it is possible to then develop interventions to match that function,
increasing the likelihood of treatment success. In addition, because behaviors that look different
can produce similar outcomes, an intervention that addresses that function should successfully
treat both behaviors. For instance, kicking a student’s chair and grabbing a book from her,
though different behaviors, likely produce similar outcomes (immediate attention from the peer).
An intervention that teaches and reinforces an appropriate alternative that achieves the same
outcome (e.g., offering to share something that is desired) has the potential to replace and reduce
both of the inappropriate behaviors.
The trend toward emphasizing function rather than form has largely been an outgrowth of
the development of functional analysis methodologies. This approach has been developed with
other populations, principally severe problem behavior of individuals with developmental
disabilities, but has since been applied to ADHD (e.g., Boyajian, DuPaul, Handler, Eckert, &
Understanding and Treating ADHD 5
McGoey, 2001; Broussard & Northup, 1997; Dicesare, McAdam, Toner, & Varrell, 2005; Ervin,
DuPaul, Kern, & Friman, 1998; Gunter, Jack, Shores, Carrell, & Flowers, 1993; Kodak, Grow, &
Northup, 2004; Northup, Broussard, Jones, George, Vollmer, & Herring, 1995; Northup &
Gulley, 2001; Northup, Kodak, Grow, Lee, & Coyne, 2004; Umbreit, 1995). For instance, Flood,
Wilder, Flood, and Masuda (2002) conducted functional analyses of the off-task behavior
exhibited by 3 children diagnosed with ADHD. The results of these analyses suggested that peer
attention served as a reinforcer for each participant’s off-task behavior. An intervention that
consisted of peer delivered redirection back to task and peer attention for on-task behavior
successfully reduced all participants’ off-task behavior.
CORE SYMPTOMS OF ADHD
Inattentiveness
Definition and Assessment
Attention deficits are viewed by many as “the major symptom construct that forms the
essential nature of this disorder” (Barkley, 2006, p. 77). They are multifaceted (e.g.,
encompassing sensory as well as motivation processes) and are often characterized as
distractability, lack of persistence, and/or failure to sustain attention. They are not clearly
operationalized (Sagvolden, Aase, Johansen, & Russell, 2005), and identifying and measuring
attention or inattention presents difficulties. Like thinking, attention cannot be directly observed
by anyone other than the person engaging in it, and its occurrence or nonoccurrence must
therefore be inferred from other behavior. Topographical definitions are often used, such as head
and eyes oriented toward materials relevant to the assigned task (e.g., Jurbergs, Palcic, & Kelley,
2007). Such definitions can be misleading or inadequate, however. One can be “daydreaming”
while looking at a math problem or, conversely, compute a math problem while not looking at it.
A functional definition of attention, on the other hand, is “discriminative responding
based on some stimulus or stimulus property. An organism is said to attend to a stimulus or
Understanding and Treating ADHD 6
property when variations in that stimulus or property change behavior” (Catania, 2007, pp. 378-
379). ADHD is usually characterized as a problem with sustained attention, which can be defined
functionally as a stimulus or stimulus property controlling behavior over time. With this
definition, attention is inferred from the outcome.
Conceptualization
From a behavioral perspective, attention deficits, as well as other symptoms of ADHD,
can be conceptualized as anomalies of delay-of-reinforcement gradients (Catania, 2005). The
effect of a reinforcer is largest when it is delivered immediately following a response, and it
becomes progressively weaker as the time interval between the response and the reinforcer
increases. For example, assume a teacher gives the student a sheet of mathematics problems.
(This serves as a discriminative stimulus signaling that reinforcement is available for problem
solving.) The student correctly writes the answer to the first problem on his paper (Response 1).
The teacher might immediately indicate that the response is correct, perhaps by revealing the
correct answer or by putting a star or “+” on the student’s paper (consequence). This has the
potential to reinforce the student’s problem solving, and also to establish the discriminative
stimulus (math problem) as a conditioned reinforcer. But suppose that, as is more typical of
classroom situations, the teacher waits until the students have had sufficient time to complete all
10 of the problems before he announces the correct answers. For students with short and steep
delay-of-reinforcement gradients, the math problem stimulus and the initial responses may be
outside the time range of reinforcer effectiveness. If the consequence is so far removed in time
from problem presentation that the problem has no opportunity to become a conditioned
reinforcer, the student most likely will not attend to it and the difficulties with sustained attention
that are symptomatic of ADHD will manifest. As noted by Catania, “A stimulus in the presence
of which an opportunity for reinforcement is likely to arise very soon is more likely to be
Understanding and Treating ADHD 7
observed or looked at or attended to than one in the presence of which that opportunity is still
some time away.” (p. 420).
Intervention Strategies
Neef and Northup (2009) describe a case that is illustrative1. The 10-year-old student with
ADHD was referred by his 4th grade teacher and the principal of an urban public elementary
school because of problems during independent seatwork. Typically during this time the teacher
distributed a worksheet containing items from math and language arts workbooks, collected the
worksheets at the end of the period, and reviewed the correct answers. The student rarely
attempted to answer any of the questions (M = 5%) and frequently engaged in disruptive
behaviors. The worksheet was then modified by inserting the correct answers with Invisible
Changeable Crayola Markers™. In this way, the student could reveal the correct answer by
coloring over the space immediately after completing the problem. With this reduction in the
delay to reinforcement, the student began to attend to the worksheet and enter answers. In an
effort to promote further improvements, immediate conditioned reinforcers were added. One
fourth of the answers were randomly designated with a star that also was revealed by coloring
over the space. If the student’s answer to a worksheet problem matched the correct answer and it
was designated with a star, he earned a point. Four points could be exchanged for a reward at the
end of the period. Indicative of attending, the student entered answers to 100% (142 of 142) of
the worksheet questions during this condition, 84% of which were correct. Similar findings were
obtained in replications with other students.
Other interventions that bring the stimulus presentation within reach of the time period of
reinforcer impact may be similarly effective. In fact, many of the behavioral treatment programs
that have been found to be effective for children with ADHD have involved increased frequency
and immediacy of reinforcement (e.g., Barkley, 2006; DuPaul & Stoner, 1994). Very short delays
1 The case is a representative participant in a dissertation conducted by Summer J. Ferreri.
Understanding and Treating ADHD 8
to reinforcement might be intermixed with progressively longer delays in order to establish the
conditional reinforcers that maintain more sustained periods of attention (Catania, 2005).
Well designed computer-based instruction may be especially well suited for this purpose
(Clairfield & Stoner, 2005; Ota & DuPaul, 2002). Its potential to automatically provide
immediate or precisely arranged consequences for responses or defined behavior sequences
relieves teachers of some of this burden. An example is Headsprout Reading Basics which, in
comparison to teacher-directed instruction, was found to produce educationally significant gains
in oral reading fluency and increased task engagement in kindergarten and first grade students
with ADHD (Clarfield & Stoner): “The student works sequentially through 40 animated lessons,
each lasting approximately 20 minutes. The program is highly interactive as the students engage
in over 180 active learner interactions per lesson. The lessons are individualized and adapt to a
child's pace. The program is designed so that the student's success rate in each lesson is at least
90%. A majority of the Headsprout activities involve the child completing tasks, which in turn
results in the moving of an animated character to a desired destination. The students keep track
of their progress through the use of a colorful progress map. After students complete a set of
episodes, they receive a Headsprout reader, which is a colorful story booklet containing the
sounds and words that the students have learned throughout the program. The Headsprout
readers also are intended to motivate students to progress through the program, as they are
distributed at regular intervals in the sequence of lessons and indicate improvement in reading
skill development. Feedback is interspersed within the Headsprout program, as every student
response is acknowledged with feedback, encouragement, and corrections if necessary. For
example, after each correct response, the computer tells the child, "yeah" or "you did it." Also,
Understanding and Treating ADHD 9
the program provides 10-30-second humorous movies to entertain the students in between
activities.”
The advantages of such approaches in enhancing attention in individuals with ADHD are
at present more theoretical than empirical. Most applied studies of interventions to increase
attention in children with ADHD have used topographical definitions which, as described earlier,
may not necessarily capture the actual phenomena of attention. Perhaps as a result, interventions
designed to increase “attending” or “on-task behavior” of children with ADHD have not always
produced concomitant changes in academic performance (e.g., Ferritor, Buckholdt, Hamblin, &
Smith, 1972).
Basic behavioral research has elucidated a great deal about attending behaviors by
focusing on functionally defined observing responses (e.g., Dinsmoor, 1985; Nevin, Davison, &
Shahan, 2005). An observing response produces stimuli correlated with the availability or
nonavailability of reinforcement (but does not have any effect upon the rate or distribution of
scheduled primary reinforcers). Because an individual must attend to a stimulus in order for it to
affect behavior, observing responses are considered a measurable accompaniment of attention
and are subject to the same principles. Several studies have extended investigations of observing
responses to applied problems with stimulus control (e.g., Dube & McIlvane, 1999; Walpole,
Roscoe, & Dube, 2007). Differential observing responses (DOR) require differential responding
to stimuli to verify that critical features have been observed. For example, Walpole et al. reported
the use of DOR with an individual with autism who had difficulty discriminating printed words
that had letters in common (e.g., cat, can, car). The DOR consisted of matching letters that
differentiated the words (e.g., t, n, r), which improved accuracy on the immediately following
task of matching whole words. Extending the generality of such research findings to ADHD is
likely to produce promising practices.
Understanding and Treating ADHD 10
Hyperactivity
Definition and Assessment
Unlike attention which must be inferred from its outcome, hyperactivity is a public event.
It is often described as persistent heightened activity, expressed topographically as pervasive
fidgeting, frequent activity changes, squirming in seat, restlessness, leaving seat, or excessive
talking and motor movements. Definitions of hyperactivity are not always operationally defined
or consistent, and often overlap with impulsivity. Applied studies often focus on problematic
behaviors that are presumed by-products or correlates of hyperactivity (e.g., aggression,
elopement) rather than on hyperactivity itself.
Conceptualization
Similar to inattentiveness, hyperactivity can be linked to the more limited temporal range
in which consequences affect behavior of individuals with short and steep delay-of-
reinforcement gradients (Catania, 2005). Specifically, for many individuals with ADHD, it is
likely that only those behaviors and stimuli that occur close to the time of reinforcer delivery are
effectively reinforced or assume conditioned reinforcer properties, such that rapid response
sequences are strengthened. Longer and slower sequences of behavior are more temporally
distant from reinforcer delivery, and therefore are more likely to occur outside the range of
reinforcer effectiveness. When rapid response sequences are differentially strengthened in this
way, a behavioral pattern that can be described as hyperactive emerges.
Intervention Strategies
Several approaches have been used to decrease the occurrence of hyperactivity. Often,
interventions consist of delivering reinforcement following successively longer and slower
sequences of behavior. Initial response requirements are small, increasing the likelihood that the
reinforcer will still be potent. This initial success may establish conditional reinforcers, which
later operate as the response requirements are increased.
Azrin, Ehle, and Beaumont (2006), for example, used an intervention based on the
Premack Principle to treat the hyperactive behavior of a 4yr old male diagnosed with ADHD.
Understanding and Treating ADHD 11
The Premack Principle (Premack, 1962) states that behaviors that naturally occur at high levels
can be used to reinforce and thus increase the occurrence of naturally low frequency behaviors.
In its application to the treatment of hyperactivity, access to physical activity such as running and
jumping (behaviors that occur frequently), would be made contingent upon completing an
academic task while seated (behavior that occurs infrequently). In the present example, the
authors targeted high levels of jumping out-of-seat and engagement in nonrelevant tasks. Using a
shaping procedure, the authors differentially reinforced progressively longer durations of sitting
calmly (which was incompatible with high levels of jumping and engagement in irrelevant tasks)
with access to the playground. Initially, the time the child was required to sit calmly was brief;
however as he demonstrated success, the time requirement was slowly increased.
Reinforcement also has been delivered via self-management interventions. A number of
studies have shown that self-management strategies in combination with reinforcement for
accurate monitoring are effective in reducing hyperactive behaviors (e.g., Ardoin and Martens,
2004; Kern, Marder, Boyajian, Elliot, & McElhattan, 1997). Ardoin and Martens taught students
how to accurately record whether or not target behaviors (looking around, playing with objects,
peer interaction, out of seat) occurred during an observation period. When accurate self-
monitoring was rewarded, targeted hyperactive behaviors were reduced.
One classroom modification often made for students with ADHD is to provide
opportunities for the students to take a break and engage in active play. The arrangement of
scheduled recess periods can be equated to a noncontingent reinforcement schedule in that access
to preferred activities, such as those that might occur during recess, are provided independent of
the type of behavior observed in the classroom. By making those activities freely available for a
period of time, students may be less motivated to engage in them immediately thereafter. As the
time from the last occurrence of the reinforcing activity increases, the activity again increases in
Understanding and Treating ADHD 12
value. This is supported by a study of the effects of recess on the classroom behavior of boys
with and without a diagnosis of ADHD (Ridgway, Northup, Pellegrin, LaRue, & Hightshoe,
2003). Recess, during which students received 10 min of outdoor free play with items such as
balls, jump ropes, and hula hoops at midmorning, was alternated with no recess across days.
Data indicated that during the baseline and no recess conditions, levels of inappropriate
behaviors (off task, inappropriate vocalizations, out-of-seat, fidgeting, and playing with objects)
increased for both groups as the morning progressed. When recess was provided, the increase in
inappropriate behavior stopped. That is, levels of inappropriate behavior during observations late
in the morning were lower on days with recess than on days without recess. Although similar
effects were observed for both groups of students, there was a greater effect for those students
with ADHD.
In another example of noncontingent reinforcement, Jones, Drew, and Weber (2000) used
peer attention delivered noncontingently to reduce high levels of talking out, getting out-of-seat,
and playing with unrelated objects by a young male diagnosed with ADHD during independent
math assignments. In comparison with contingent attention, noncontingent peer attention reduced
disruptive behavior to near zero levels. As with self-management techniques, peer-delivered
consequences are advantageous as they decrease the demand on teachers to monitor behavior and
deliver intervention components.
Impulsivity
Definition and Assessment
Impulsivity is a construct that, outside of the behavioral literature, is often defined
topographically by describing various forms of behavior considered to be impulsive. For
example, the DSM-IV (2000) describes impulsivity as “impatience, difficulty in delaying
responses, blurting out answers before questions have been completed, difficulty awaiting one’s
Understanding and Treating ADHD 13
turn, and frequently interrupting or intruding on others to the point of causing difficulties in
social academic or occupational settings.” (p.86).
Impulsivity can be described functionally as behaving in ways that produce more
immediate outcomes. For example, the child who calls out in class is likely to get the teacher’s
attention sooner than if he had raised his hand and waited for the teacher to call his name. In
behavioral research, impulsive behavior is usually defined as choosing a smaller or less preferred
reward that is immediate over a larger or more preferred reward that is delayed (Ainslie, 1975).
In contrast, self-control is exemplified as choosing the larger, later reinforcer (LLR) over the
smaller, sooner reinforcer (SSR). This functional account of impulsivity lends itself to objective
and precise measurement. Research using these measures has indicated that the choices of
children with ADHD are especially likely to be governed by reductions in delay to reinforcement
(e.g., relative to their peers, they are more likely to choose SSR over LLR) (Hoerger & Mace,
2006; Neef et al., 2005; Neef, Bicard, & Endo, 2001; Schweitzer & Sulzer-Azaroff, 1995;
Sonuga-Barke, Taylor, Sembi, & Smith, 1992).
For example, Neef et al. (2005) conducted a functional assessment of impulsivity
involving objective measurement of the extent to which the value or effectiveness of a
consequence is a function of its immediacy relative to other possible dimensions (e.g., quality,
rate, effort). Computer-based assessments were conducted with 58 children (including 32
children with a diagnosis of ADHD) by arranging choices between academic tasks (math
problems that participants were able to complete); students could choose to complete a problem
that resulted in an immediate consequence that was less favorable with respect to another
dimension (e.g., low preference reward delivered at the end of the session) or a problem that
resulted in a delayed consequence that was more favorable with respect to that same dimension
(e.g., a highly preferred reward delivered the next day). Examination of response patterns as well
Understanding and Treating ADHD 14
as of the percentage of choices that were made to the respective alternatives indicated the extent
to which each student’s behavior was influenced by immediacy of reinforcement or by another
dimension. For example, the behavior of a student who consistently selected the response option
that produced immediate reinforcement even when it resulted in less preferred rewards, fewer
rewards, or required more effort relative to the alternative would be characterized as impulsive.
On the other hand, favoring the response option that resulted in a more preferred reinforcer even
when it was delayed, or allocating responding in a way that produced the most reinforcement
from each alternative, would be indicative of self-control.
Hoerger and Mace (2006) also conducted a computerized functional assessment of
impulsivity in which 30 children (15 of whom had ADHD features) participated. Similar to Neef
et al. (2005), Hoerger and Mace found that impulsiveness characterized the choices of more
children with ADHD features than children in the control group. In addition, impulsive choices
on the functional assessment correlated with direct measures of classroom behavior (gross motor
activity) characteristic of ADHD.
Conceptualization
According to the delay-of-reinforcement model, immediate reinforcers are more likely to
fall within the range of reinforcer effectiveness than delayed reinforcers, with the resultant
selection or strengthening of behavior that is impulsive (Catania, 2005).
Intervention Strategies
One of the simplest techniques designed for decreasing impulsive behavior is the use of a
progressive delay. Initially a choice between small and large reinforcers is provided when there
is either little or no delay to either alternative. Under these conditions, choice allocation is likely
to be toward the larger reinforcer as there is no delay that might reduce its relative value. For
example, a parent might initially ask a child to choose between one cookie available immediately
and three cookies available immediately. Once consistent choice of the larger reinforcer is
Understanding and Treating ADHD 15
established (i.e., the three cookies), a delay is introduced and then systematically increased while
maintaining choice allocation towards the larger reinforcer. In our example with the cookies, the
single cookie will still be made available immediately; however, choosing the three cookies will
require a brief wait before the cookies are delivered. Through repeated success at contacting
delayed reinforcement, progressive delays slowly strengthen self-control.
In a study by Schweitzer and Sulzer-Azaroff (1988) a progressive delay was used to
increase the self-control of 6 young children who were described as impulsive and hyperactive.
First a pre-assessment was conducted to determine the delay length at which the children were
just as likely to choose one alternative as the other (i.e., the indifference point). During
subsequent self-control training, the delay to the larger reinforcer was increased, in 5 s
increments, from an initial value of zero seconds. Throughout the training phase almost all
participants chose the larger delayed reinforcer exclusively. When indifference points were
reassessed, results indicated that 3 of 5 students chose the larger-later reinforcer at delays greater
than those trained. In addition, no indifference point was established for 3 children because it
was higher than those values tested during the post assessment. Several explanations were
presented for the increase in tolerance for delay. First it is possible that the progressive delays
helped to shape and strengthen an activity that the child engaged in during the wait time. For
example the children may have formed “rules” related to the delay and then stated them covertly.
In addition, the lights on the apparatus that signaled the trials may have functioned as a
conditioned reinforcer for choosing the larger-later alternative. The results of this study
demonstrate one way of increasing self-control for children with ADHD. When attempting to
teach self-control, initially the delay to the reinforcer should be very short. Once a child is
repeatedly choosing the larger reinforcer, small increases in the wait time should be introduced
until the desired delay has been met.
Understanding and Treating ADHD 16
Progressive delays often are used in combination with other interventions such as
intervening activities or competing reinforcer dimensions. For instance, Neef, Bicard, and Endo
(2001) conducted a functional assessment of impulsivity (as described with Neef et al., 2005)
with three students diagnosed with ADHD, which showed that their choices were principally
governed by reinforcer immediacy. The next most influential dimension as indicated by the
assessment (reinforcer quality for two of the students and reinforcer rate for one student) was
then arranged to compete with reinforcer immediacy. Thus, for example, the two students for
whom reinforcer quality was an influential dimension were allowed to choose between math
problems associated with immediate low-quality reinforcers and delayed high quality reinforcers.
Initially, the delay for the high quality reinforcers was minimal; once it was selected consistently,
the delay was increased gradually. When combined with a progressive delay, the competing
reinforcer dimensions promoted self-control for delays lasting up to 24 hours. Another finding of
this study was that the self-control developed with one reinforcer dimension persisted when other
reinforcer dimensions were retested. That is, after self-control training, the participants continued
to demonstrate self-control in situations different than those in which the training occurred.
Intervening activities are often used as a means of filling the gap between a response and
later delivery of the reinforcer. From a procedural standpoint, once the initial choice for a
delayed reinforcer has been made, the individual is then provided access to an activity in which
to engage during that delay. There are several possible functions that the intervening activity may
serve. First, it is possible that engaging in the intervening activity serves as a competing response
that interferes with attending to the delay. For example, airport terminals provide access to
televisions as a means of bridging the delay to boarding the airplane. On the other hand, an
intervening activity may increase attending toward the impending delivery of the delayed
Understanding and Treating ADHD 17
reinforcer, or the reduction in delay. For instance, when exercising for a specific duration of time,
some individuals frequently check the stopwatch on the exercise machine. Seeing progress
towards meeting their exercise goal for that day helps to bridge the delay to the end of the
workout.
Investigations of intervening activities have included efficacy in increasing tolerance for
delay, comparison of various activities, and preference for intervening activities. For example,
Mischel and colleagues conducted a series of studies that focused on the impulsive behavior of
typically developing preschoolers. In one study Mischel, Ebbesen, and Raskoff Zeiss (1972)
examined the effects of various intervening activities on the length of delay that the preschoolers
could tolerate prior to consuming a preferred edible item. The procedures for these experiments
were relatively simple. The experimenter provided an initial choice between two small edibles.
Once the child made a selection, he (or she) was informed that he could consume the low-
preference item (i.e., the item he had not chosen) now or the high-preference item after a delay.
During the delay the experimenter left the room, but if the child rang a bell, the experimenter
returned and provided access to the low-preference item. If the child did not ring the bell, the
experimenter returned to the room after 15 minutes and provided access to the high-preference
treat. Intervening activities compared included access to a toy and various instructions such as
“think fun thoughts,” “think sad thoughts,” and “think about the reward.” Results indicated that
the children who were provided with an intervening activity waited longer than those who were
not provided with an intervening activity. In addition, instructions to “think fun thoughts”
produced a longer mean duration of waiting than access to a toy, while instructions to “think sad
thoughts” or “think about the reward” produced shorter durations of waiting.
As suggested by the Mischel studies, the relative preference for an intervening activity
(e.g., “think sad thoughts”) does not appear to be a crucial factor in its overall efficacy in
Understanding and Treating ADHD 18
increasing tolerance for delay, although some tasks appear to be more effective than others.
Binder, Dixon, and Ghezzi (2000) compared the effectiveness of recitation of rules about the
delay and a verbal academic task in increasing the self-control of young children with ADHD.
Results of a multielement design comparison indicated that preference for the larger-later item
remained high regardless of the intervening activity. In addition, during an alternative activity
condition (when either the verbal recitation was changed to an unrelated phrase or no intervening
activity was provided), preference for the larger-later item remained high. The results for the
participants whose alternative activity condition consisted of no intervening activity suggest that
self-control may maintain following the removal of the intervening activity.
This research, as well as research with other populations (Dixon & Cummings, 2001;
Dixon & Halcoumb, 2000; Dixon et al. 1998; Dixon, Horner, & Guercio, 2003; Dixon, Rehfeldt,
& Randich, 2003), has shown intervening activities to be an effective means of treating
impulsive behavior. The intervening activity does not have to be preferred nor related to rules
regarding the delay. In addition, it appears that, given a choice, people tend to prefer an
intervening activity over no activity. Indeed, Gordon (1979 ) observed that 90% of participants
diagnosed as hyperactive independently engaged in behaviors such as counting, swinging legs,
singing, or foot- or finger-tapping during a task that required them to withhold button presses for
a set interval in order to receive a reward. He speculated that such intervening activities
(“mediating behaviors”), while reflecting efforts at self-control, might be characterized as
hyperactivity.
Intervening activities can be applied within a group arrangement in order to increase
engagement in a cooperative task. Collectively, research suggests that self-control is more likely
to be demonstrated if an intervening activity is provided. In addition, interventions that include
intervening activities during delays to reinforcement are likely to be adhered to more than those
Understanding and Treating ADHD 19
that do not include intervening activities. Finally, the activity provided during the delay period
does not need to be one that is of high-preference; rather low-preference activities such as
academic tasks can also be effective.
Another potential means of promoting self-control over impulsivity is through the use of a
commitment response. Specifically, a choice that binds one to a later selection of a large delayed
reward over a small immediate reward can be made at a time when the reward is remote and
therefore less valued (temporally discounted). Although the potential of this strategy to enhance
self-control in individuals with ADHD remains to be investigated, findings from basic laboratory
research suggest that it may offer a promising alternative (Rachlin & Green, 1972; Siegel &
Rachlin, 1995).
MEDICATION MANAGEMENT
Stimulant medication, including methylphenidate (Ritalin), dextroamphetamine (Dexedrine),
and magnesium pemoline (Cylert), is the most common treatment for ADHD, and there is ample
support for its use (The MTA Cooperative group, 1999).The Multimodal Treatment Study of
Children with ADHD (MTA) found medication management to be particularly effective in
attenuating core ADHD symptoms (inattention and hyperactivity). This has been supported by
within-subject studies as well. For example, Mace et al. (2009) showed higher levels of task
engagement and fewer activity changes during medication (Concerta XL) than during placebo
conditions in an adolescent with ADHD.
Although there is little question that pharmacological treatment can be beneficial, it is not a
panacea. First, the improvements achieved with medication have not always been sufficient. For
example, Mace, Prager et al. (2009) showed that problem behavior (e.g., aggression) was
reduced with stimulant medication relative to placebo, but not to acceptable levels.
Understanding and Treating ADHD 20
Second, medication interacts with environmental conditions to affect behavior; if the
behavioral mechanisms of drug action are unknown or uncontrolled, medication is likely to have
inconsistent or seemingly idiosyncratic effects. This was illustrated clearly by Northup et al.
(1999). They examined the effects of different conditions and contingencies commonly observed
in classrooms on the disruptive and off task behaviors of children diagnosed with ADHD under
methylphenidate versus placebo conditions. When the students were asked to work by
themselves (alone condition), high levels of disruption and off task behavior occurred under
placebo as well as medication conditions. However, medication reduced the target behaviors
relative to placebo for each student in one or more of the other classroom conditions (teacher
present but with no interaction, contingent teacher reprimands, contingent brief timeout).Thus,
medication reduced problem behavior under some environmental conditions but not others, and
the effects differed across students.
Finally, as noted by DuPaul and Stoner (1994), “It appears as though problems with
inattention, impulsivity, and overactivity predispose children to other difficulties that are, in
some cases, more severe than the core deficits of ADHD.” (p. 4). ADHD places individuals at
risk for academic underachievement, disturbances in peer relationships, and difficulties in a
number of areas of functioning. Stimulant medication alone has not typically been sufficient to
address these concerns. For example, unless combined with psychosocial treatment, medication
was not found to produce significant improvements on measures of classroom behavior or
ratings of social skills (The MTA Cooperative Group, 1999), and its effectiveness in improving
academic performance or learning has been questioned (see Purdie, Hattie, & Carroll, 2002).
Indeed, considering that as many as 80% of children with ADHD have been found to exhibit
academic performance problems (Cantwell & Baker, 1991) despite stimulant medication being
Understanding and Treating ADHD 21
the most commonly used treatment, it seems an unrealistic expectation for medication to
shoulder sole responsibility for addressing these children’s needs.
The issue of medication is a continuing controversy. We believe that the relevant question is
not whether medication is better than behavioral intervention overall, but (a) how, and the
conditions under which, each operates to produce the desired outcomes (such that effects can be
better predicted), and (b) the most efficacious treatment(s) for each individual. The former will
require continued research (e.g., Neef, Bicard, Endo, Coury, & Aman, 2005). The latter can be
best addressed through systematic assessment, and several approaches for this purpose have been
examined. Cooper et al. (1993) presented a model for efficiently assessing the relative effects of
medication and function-based treatment on target behaviors. The assessment model,
incorporating brief functional analyses, was illustrated with two cases, and Kayser et al. (1997)
applied it to another case. Assessment results in Cooper et al. indicated improved behavior with a
combination of methylphenidate (MPH) and alteration of environmental variables in one case.
For the other, alteration of environmental variables improved behavior regardless of medication
usage. Assessment results in the Kayser et al. case indicated that inappropriate behavior, which
functioned primarily to escape demands, was reduced to near-zero levels with behavioral
intervention regardless of MPH, and that sleep improved without MPH.
Gulley et al. (2003) similarly described a practical and relatively efficient method of
evaluating the separate, relative, and combined effects of varying dosages of stimulant
medication and different behavioral interventions to determine the most effective treatments for
individual children. Illustrative cases were presented in which MPH and differential
reinforcement of other behavior (DRO) were each used separately and then in combination.
Thereafter, an increase in MPH dosage, a change in behavioral treatment (DRO plus either
Understanding and Treating ADHD 22
response cost or timeout contingent on disruptions), or both were implemented in sequential
phases. The behavioral treatment was presented during only one of two daily observation
sessions, and MPH and placebo were alternated as well. Individualized behavioral treatments
resulted in decreases in disruptive behavior equivalent to MPH in each case.
Curriculum-based measurement (CBM) offers a promising means of assessing the relative
effects of treatments on academic performance. Data are derived from brief fluency measures of
student performance in basic academic skill areas, using material samples from the student’s
curriculum. Extensive research supports its technical adequacy from both behavioral and
traditional psychometric perspectives, and its sensitivity to changes resulting from educational
interventions (Fuchs & Dino, 1991). Stoner, Carey, Ikeda, and Shinn (1994) examined the utility
of CBM of reading and math for evaluating student response to three dosages of MPH. The
results provide preliminary support for its use as a sensitive measure of medication effects on
academic performance, and for making decisions regarding stimulant medication.
CONCLUDING REMARKS
Functional definitions of the main clinical symptoms of ADHD not only provide
understanding as to why these behaviors occur but also inform their treatment. To date, function
based interventions have received varying degrees of attention in the applied literature. As a
private event, inattentiveness may be the most difficult symptom to address. Although further
applied behavioral research is needed in this area, a theoretical foundation for attending can be
found in the basic behavioral research. Hyperactivity and impulsivity on the other hand, have
been studied in applied settings. Treatments for hyperactivity that differentially reinforce longer
and slower sequences of behavior have been shown to be effective. In addition, impulsivity has
been decreased via procedures that establish success in obtaining delayed reinforcement, provide
alternative activities during delays, and increase the relative value of delayed reinforcers.
Understanding and Treating ADHD 23
Collectively, the success of these interventions demonstrates the utility of functional approaches
to the treatment of ADHD. Stimulant medication can affect behavior by altering sensitivity to
antecedents or consequences. Optimal treatment requires systematic assessment for prediction of
treatment(s) most likely to be efficacious for an individual, as well as monitoring and evaluation
of outcomes.
Understanding and Treating ADHD 24
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