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Determine the direction of the behavior
Alignment with an outcome or goal
Energy
Determines the intensity or strength of the engagement
Endurance
Time endurance of the commitment
The internal motives (needs, cognitions, emotions) serve as mediators between external triggers on the one hand and behavior/performance on the other.2
ADHD sufferers require on average significantly higher extrinsic (external influence, e.g., rewards, compulsions, threatened punishments) or intrinsic (from within themselves / from the thing itself) incentives than do non-affected individuals to achieve the same personal motivation.
We think that this leads to the fact that motivation in ADHD is (somewhat) more strongly directed towards the satisfaction of one’s own needs and is weaker guided by the needs of others than in non-affected individuals.
What may look like slightly increased egoism from the outside, however, is a non-conscious shift in what can arouse individual motivation and is not subject to conscious controllability by the individuals concerned.
The relationship between inattention and (poor) academic performance is explained by the level of concurrent intrinsic motivation and behavioral engagement, but not by the level of concurrent hyperactivity/impulsivity, behavior problems, or anxiety.6
Motivation or motivability (as well as attention) is not disturbed per se in ADHD, but is subject to a different mode of regulation / control profile. When motivation is particularly high, ADHD sufferers can hardly be distinguished from non-affected persons (even in attention tests). The difference lies rather in the lower self-motivability, which can easily be mistaken from the outside for unwillingness, laziness.
We suspect that motivability is more focused on satisfying one’s own needs than is the case for non-affected individuals.
To us, this would be a logical consequence of the fact that ADHD symptoms are mediated by the same neurophysiological pathway as symptoms of chronic stress (primarily decreased dopamine and norepinephrine levels in dlPFC, striatum, and cerebellum). One stress benefit is increased assurance of self-survival. In this context, a tendency to prioritize selfish behaviors would be expected. To date, we have found very little research examining ADHD and selfishness. One study of 90 ADHD-affected adults found significantly increased egocentrism.7 Another study found a weak correlation between selfishness/narcissism (as well as callous unemotional traits) and ADHD.8
Not meant, but possibly correlating, is that ADHD sufferers seem to be worse at taking the (visual) perspective of an interlocutor.9
Intrinsic needs can be addressed by intrinsic motivation/interests, where the thing itself arouses the interest/motivation of the individual, as well as by extrinsic motivation/interest (constraints, threatened punishments, rewards).
Hypothesis of shift in motivability toward intrinsic needs questionable / not proven so far
We had previously assumed that intrinsic motivability would be less impaired and that motivability would be shifted toward intrinsic motivation. Studies so far do not confirm this, with probably only studies related to academic intrinsic motivation in ADHD.
What does emerge, however, is a reduced neurophysiological response to anticipated (expected) rewards and an increased neurophysiological response to received rewards, which may explain the shift in motivability toward immediately available rewards and the associated devaluation of distant rewards (reward discounting).
We have not yet found any research to support our hypothesis that this is associated with a shift in motivability toward the satisfaction of personal needs.
1.1. Motivability through extrinsic / intrinsic incentives¶
As many studies show, extrinsic motivability is weakened in ADHD compared to non-affected individuals. Extrinsic incentives must therefore generally be significantly higher in ADHD than in non-affected individuals in order to arouse the same level of motivation.10
In the following, this article contains many references to sources that show that in ADHD increased extrinsic incentives are able, through the motivation thus achieved, to reduce various symptoms to such an extent that they are no longer much more noticeable than in non-affected persons or even reach the level of non-affected persons, e.g. (sustained) attention, inhibition (impulsivity suppression), parts of working memory, and probably also frustration intolerance tends to be reduced. For most other ADHD symptoms, the effect of motivation created by increased incentives has not yet been studied.
1.1-2. Intrinsic motivability also attenuated in ADHD¶
One study on (academic) intrinsic motivability in ADHD found that it also seems to be attenuated, affecting ADHD-C and ADHD-I equally.11 Another study found that in adolescents with ADHD the academic intrinsic motivability with d = 0.49 was weakened somewhat more than the academic extrinsic motivability with d = 0.43 (in each case in comparison to non-affected persons).12
Another study hypothesizes that a slower event rate on tests in ADHD sufferers results in reduced intrinsic motivation due to their peculiarities in motivability.13 The authors further suggest that under certain circumstances, an external incentive can undermine an individual’s intrinsic motivation. However, this generally well-studied effect has not yet been tested in ADHD sufferers.
One report addresses the importance of intrinsic (internal) motives in ADHD and their capture by Self Determination Theory (SDT).2
1.2. Reward sensitivity by behavior / autonomic nervous system activity¶
Reward sensitivity can be divided into external reward sensitivity, defined as behavioral approach motivation in response to reward (i.e., reward-seeking behavior)14, and internal reward sensitivity, defined as the nervous system’s threshold for responding to reward, indexed by sympathetic nervous system activity, nucleus accumbens, or dopaminergic fronto-striatal brain regions)15.
In terms of behavioral reward sensitivity in children with ADHD, results suggest increased reward sensitivity in ADHD, with high rewards showing a very large effect and immediate rewards being significantly preferred.16 Some studies concluded increased behavioral reward sensitivity in children with ADHD due to
A preference for small immediate rewards compared to larger delayed rewards17
Depreciation of delayed rewards / delay discounting18192021
One small study found no difference in ADHD, but a decrease with age22
One study found a 27% reduction in behavioral reward sensitivity in ADHD (5.0 pops) compared to unaffected (6.35 pops) using the Balloon analogue risk task (BART), which we do not believe is consistent with the authors’ assessment of no differences. The decreased behavioral reward sensitivity in ADHD was also evident in measures of PEP (prolonged in ADHD) and RSA (HRV decreased).24 The groups differed significantly in gender distribution (55% boys TD vs 85% boys with ADHD).
1.2.2. Response threshold of the autonomic nervous system¶
Regarding neurophysiological reward sensitivity in children with ADHD, the results suggest an altered autonomic nervous system response threshold in ADHD.25 PEP was shown to be prolonged and RSA (HRV) decreased in ADHD.24
PEP and RSA: what they mean
The PEP represents the mesolimbic dopamine reactivity especially during the reward response.26 A longer PEP is a marker for reduced sympathetic nervous system activity, although this may be co-determined by other factors.27
Respiratory sinus arrhythmia (RSA) consists of oscillatory increases and decreases in heart rate during the respiratory cycle. It represents parasympathetic/vagal effects on the heart. The RSA is thought to represent neural traffic through the vagus nerve28. The vagus nerve is thought to represent a physiological mechanism for rapid acceleration and deceleration of cardiac output (heart rate variability, HRV) in response to environmental (including social) demands.29
ADHD subtypes seem to differ in terms of the incentives that can increase their motivation. One hypothesis in this regard is that different ADHD subtypes might be helped by different incentives to improve their motivation. ADHD-C, who (like the predominantly hyperactive ADHD-HI subtype) carried more competitive traits, should be better incentivized by the use of game-like learning approaches and public recognition of their performance, whereas the predominantly inattentive ADHD-I subtype, who carried more cooperative traits and was more often distracted by their own intrinsic curiosity, would be more likely to be motivated by cooperative learning and social feedback. This applies in particular to instructional interventions and the style of didactic support for learning.11
In studies of reward behavior, different incentives are used according to type (e.g., money, gifts, points, computer games) and intensity of reinforcement (e.g., 5 ct, 25 ct, 1 point, 100 points)….30
The fact that some studies found no change in ADHD symptoms due to rewards could possibly be due to the fact that the respective rewards were not able to arouse the individual’s interest sufficiently.30. The authors’ study on working memory in ADHD, however, found a significant improvement even with very high rewards, but not a complete equalization of working memory performance compared to non-affected persons.
Monetary rewards tend to show the strongest motivational incentive.
One study found that while social rewards improved impulsivity relatively more than in nonaffected individuals, again monetary rewards were the strongest motivator in both ADHD sufferers and nonaffected individuals.31
As rewards, monetary incentives seem to work better (for women) than punishments to be avoided through verbal feedback.32
2. Attention in ADHD: not disturbed, but different¶
Attention in ADHD differs significantly from that of non-affected individuals. Nevertheless, the ability to pay attention per se is not impaired in ADHD. The directability itself is also unchanged - attention in ADHD can be very focused (keyword: task switching problems, hyperfocus) or easily switch (keyword: distractibility).
Attention differs in ADHD from nonaffected individuals in that its guidance is subject to a different control profile. ADHD correlates with a decreased neurophysiological response to anticipated (expected) rewards and an increased neurophysiological response to received rewards, which explains the shift in motivability toward immediately available rewards and the associated devaluation of distant rewards (reward discounting).
We hypothesize that attention directing in ADHD is more dependent on high individual motivation. If something is personally highly interesting, the attention can stay well with this thing, if it is not very interesting, the attention changes more easily than in non-affected persons. Attention directing is much more dependent on satisfying one’s own needs in ADHD than in non-affected individuals. However, this is not selfishness, but an altered control of motivation over which the affected person has no control.
What looks from the outside like a “You can if you want to” is actually a “I can’t want as I should.”
Non-affected individuals are subject to the same deviant attentional control profile when they are in severe acute or chronic stress. For such emergencies (e.g., life-threatening situations), such an attentional pattern is helpful and has been useful in survival for the last millennia.
The problem we see in ADHD is that this attention control profile is permanently activated even though there is no corresponding life-threatening situation.
Even if it initially seems logical that a weakening of motivability is associated with things that are of personal interest becoming relatively more prominent, we have not yet been able to find any scientific evidence for the hypothesis that motivability shifts toward personal interests.
Brown refers to the interest-driven change in attention for ADHD as a tendency to focus attention excessively on things that interest.33 Anxiety and depression are subject to a similar perceptual bias toward the distressing/scary topics.3435
In ADHD, deactivation of the default mode network (DMN), which is deactivated when attention to external stimuli is activated, is reduced. Rewards of interest, such as stimulants, are able to bring the deactivation of the DMN in ADHD sufferers into line with that of non-affected individuals.36
The focusable attention of ADHD sufferers is also reflected in the fact that they can achieve the same performance on ADHD tests as non-affected individuals if they have a high level of personal interest in the test. This often leads to false negative test results. (Extrinsic) rewards that are high enough to arouse personal interest produce the same result.3738394041
One study found that frequent reinforcement leveled differences in sustained attention between ADHD sufferers and nonaffected individuals, while infrequent reinforcement allowed the differences to persist. This had particularly affected younger children.42
More on this at ⇒ ADHD sufferers perform as well as non-affected individuals on tests given the right level of interest
The fact that an insufficiently stimulating environment (underactivation) can also cause inattention in healthy individuals, e.g., in gifted students in schools that are not suitable for gifted students,43, on the other hand, is probably not due to an altered control profile of attention, but rather to an underchallenge that causes boredom.
2.1. Task switching problems and distractibility in ADHD¶
If something individually particularly interesting (high individual motivation) is done, task switching problems arise. The attention is strongly absorbed and a change of attention to other things is difficult. This condition is called hyperfocus in the extreme, and the resulting symptom is task switching problems.
If the current activity is not individually particularly interesting, on the other hand, distractibility is increased. Attention is then less focused and easily directed toward new stimuli.
3. Inhibition problems disappear when individual motivation is high¶
Impulsivity in ADHD (inhibition ability) can also be influenced by rewards.44 Rewards led to stop-task results in children with ADHD that were similar to those of controls, whereas the same rewards improved inhibition less in children with brain injury.45 Here, the reward for a successful stop task consisted of immediate positive feedback on the screen (e.g., “Well done”/“Great”/“Keep up the good work”) and a point added to the score, which children could convert to candy or small toys after the test.
Another study also found identical inhibitory ability of ADHD sufferers and nonafflicted individuals to high rewards.46
Another study found a greater improvement in inhibition and sustained attention in ADHD sufferers than in non-affected persons,31. Another study found no improvement in inhibition ability with rewards.47 The reward here was 25 dollar cents for a successful inhibition in a modified stop-task test at the same time as a loss of 10 dollar cents for a failed test pass. It is conceivable that the form of reward in this test could not arouse sufficient individual motivation.
Several studies show that rewards improve inhibition skills not only in ADHD but also in substance abuse or gambling addiction.48
One review summarizes that in ADHD, impulsivity correlates with decreased activity of the striatum during reward anticipation, whereas in healthy individuals, impulsivity is associated with increased activity of the striatum during reward anticipation.49
4. Reward improves working memory and sustained performance in ADHD¶
ADHD is associated with impaired working memory.
In one study, children with ADHD showed significant improvements in working memory for rewards, but did not reach the level of unaffected individuals even for the strongest rewards (€10 and gaming). Only children with ADHD showed a decline in performance over the test duration. However, high rewards were able to eliminate this drop in performance.30
One study found that in children ADHD-C rewards (feedback after each run and points redeemable for prizes) improved visuospatial working memory with respect to manipulation of stored visuospatial information (backward span). In contrast, no improvement was found with respect to the storage of visuospatial information (forward span). A comparison with non-affected subjects was not made.50
Another small study also found improvements in visuospatial working memory from extrinsic rewards.51
One study found that the frustration still detectable in ADHD subjects at low rewards in the first test sessions did not occur at higher rewards.41 Another study found no improvement in frustration tolerance in ADHD with rewards.52
6. Impatience and procrastination in ADHD: motivation differs¶
Things with high personal motivation have to happen right now for ADHD sufferers. Impatience and not being able to wait are typical consequences of this.
In contrast, things for which there is low personal motivation are procrastinated more often than by non-procrastinators, such as opening unpleasant mail (as opposed to the longed-for call from a loved one), doing the tax return, or taking down the trash.
This pattern exists in all people to some degree. In ADHD, however, it is drastically increased and leads to dysfunctional outcomes.
Emotional instability correlated with decreased activation of the striatum during reward expectancy in a study of healthy individuals only in women but not in men.53
In a Go/Nogo task, children with ADHD responded more slowly and variably than their unaffected siblings or controls. A slower event rate did not reduce the performance of the ADHD-affected children. Under reward, only the ADHD-affected and their unaffected siblings showed accelerated mean reaction times and lower response variability, but not controls, whereas accuracy improved in all 3 groups. Males responded faster and showed more false alarms, regardless of ADHD status.54
As of 2013, no published study had examined the impact of rewards on delay discounting in ADHD.55
It is colocated that children with ADHD do not show symptoms of attention problems, distractibility, or hyperactivity when they engage in an intrinsically highly motivating activity (e.g., computer games).
The changes in motivation in ADHD, including the neurophysiological correlates underlying them (decreased dopamine levels/decreased activation in the nucleus accumbens with anticipated reward and increased activation de nucleus accumbens with received reward), correspond to those in chronic stress. ⇒ Neurophysiological correlates of reward in ADHD
This is consistent with our hypothesis that symptoms of ADHD and symptoms of chronic stress are mediated by very similar neurophysiological mechanisms (primarily dopamine and norepinephrine deficiency in dlPFC, striatum, and cerebellum).
Barkley (2015). ADHD as a Motivation Deficit Disorder. In Barkley (Herausgeber): Attention-deficit hyperactivity disorder: A handbook for diagnosis and treatment (pp. 22–23). ↥
[Humphreys, Lee (2011): Risk Taking and Sensitivity to Punishment in Children with ADHD, ODD, ADHD+ODD, and Controls. J Psychopathol Behav Assess. 2011;33(3):299-307. doi: 10.1007/s10862-011-9237-6. PMID: 33132494; PMCID: PMC7597674.](https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7597674/ ↥
[Ritz (2009): Studying noninvasive indices of vagal control: the need for respiratory control and the problem of target specificity. Biol Psychol. 2009 Feb;80(2):158-68. doi: 10.1016/j.biopsycho.2008.08.003. PMID: 18775468.](https://pubmed.ncbi.nlm.nih.gov/18775468/ ↥
