3. Impulsivity / inhibition problems in ADHD

Impulsivity is generally defined as spontaneous reactions to internal impulses or external stimuli, without consideration of even obvious consequences. The behavior is perceived by third parties as inappropriate to the situation, uncontrolled or thoughtless. Excessive impulsivity is referred to as impulse control disorder (inhibition). Impulsivity has advantages in certain life situations where rapid focus and quick decisions are required and appears to be primarily dopaminergically controlled.¹

• 3. Impulsivity
  • 3.1. Inhibition problems / Action impulsivity (AI)
  • 3.2. Choice impulsivity: devaluation of distant rewards (delay aversion, reward discounting, choice impulsivity, CI)
  • 3.3. Impulse control problems / inhibition problems as ADHD symptoms
    • 3.3.1. Manifestations of inhibition problems in children
    • 3.3.2. Manifestations of inhibition problems in adults
  • 3.4. Impulse control problems as symptoms of stress
  • 3.5. Increased willingness to take risks
    • 3.5.1. Increased risk-taking as an ADHD symptom
    • 3.5.2. Increased risk taking as a symptom of stress
  • 3.6. Novelty Seeking / Sensation Seeking

3. Impulsivity¶

Impulsivity is divided into:²

• responsive impulsivity / action impulsivity (AI)³
• cognitive / choice impulsivity (CI)⁴

3.1. Inhibition problems / Action impulsivity (AI)¶

Handler impulsivity manifests as:

• Tendency to act immediately, with diminished foresight and out of context with current environmental demands
  • a reduced ability to inhibit prepotent responses
  • a failure of voluntary motor inhibition or disinhibition (inhibition)
• Consequence of a problem of self-regulation and thus inhibition.⁵⁶ Inhibition is the ability to suppress an impulse.
  Inhibition problems are primarily attributed to ADHD-HI and ADHD-C.⁷
  Inhibition problems often manifest themselves, but not only through impulsivity problems.

Symptoms of action impulsivity in ADHD include:⁸

• Excessive talking
• Blurting out
• Not be able to wait for one’s turn
• Interrupt

Impulsivity is something other than an affect breakthrough.
Affect breakthroughs are (brief) emotional outbursts, i.e., intense uncontrolled reactions, e.g., brief outbursts of anger.

As is known from decision research, the signal to perform an action can be measured up to 10 seconds earlier than the person is aware that he or she has made a decision.⁹ Even 200 milliseconds before execution, the person can abort the decision that has already been made.¹⁰
The long duration between the start of the signal and the actual execution of the decision ultimately serves to ensure that the “made” decision can still be stopped for a relatively long time. Many instances are actively involved in the process of inhibition, that of stopping a decision option.
Figuratively, one area of the brain puts decisions “up for discussion” and gives other brain regions the opportunity to evaluate them and then allow or disallow them.

This testing and aborting mechanism is controlled quite significantly by dopamine. If the dopamine control circuit is disturbed, the mechanism that serves to abort decisions is impaired. A disturbance of inhibition is conceivable, for example, in that the dopamine levels are too low or too high, so that the signal transmission is too weak or noisy, so that the weakening (inhibitory) impulse does not arrive.
The known dysfunction of the dopamine system explains the impulse control problems in ADHD.

3.2. Choice impulsivity: devaluation of distant rewards (delay aversion, reward discounting, choice impulsivity, CI)¶

Even though elective impulsivity is a form of impulsivity, we will continue to discuss it in the Motivation chapter for now.

Elective impulsivity includes:

• Devaluation of more distant rewards, while immediate rewards have unchanged effect^11126131415
  • Preference for immediate (small) rewards over more distant larger ones
  • Devaluation of more distant rewards is a symptom that occurs not only in ADHD, but also in other disorders such as addiction or major depression.¹⁶
  • overlaps conceptually with
    • Impairment of decision making
    • Delay aversion (temporal discounting or delay discounting). Delay discounting is the phenomenon in which a delayed outcome of a choice reduces the subjective value of a reward and maps onto the operational measure of decision impulsivity.¹⁷¹⁸

Immediate reward and delayed reward are mapped by different brain systems:¹⁹

• Decisions about immediately available rewards:
  • Parts of the limbic system connected to the midbrain dopamine system, including the paralimbic cortex
• intertemporal decisions regardless of delay:
  • Regions of the lateral prefrontal cortex and posterior parietal cortex
• Decisions for longer-term options:
  • correlate with relatively greater fronto-parietal activity

Impulsivity appears to result from avoidance of negative affective states associated with delay. ADHD sufferers perceive a delay before (personally desired) outcomes or events as particularly aversive, which reinforces the motive to avoid this delay. Fittingly, in ADHD, the amygdala is hypersensitized to cues of delay (of personally desired events).²⁰

ADHD appears to be related to suboptimal timing decision making (as an example of inconsistency) rather than steeper delay discounting. High ADHD symptoms were not only associated with less frequent choice of the delayed option when it was better, but also with more frequent choice of the delayed option when it was not better. In addition, ADHD was associated with higher inconsistency in both cases.²¹

3.3. Impulse control problems / inhibition problems as ADHD symptoms¶

On the neurophysiological causes of impulsivity and inhibition problems ⇒ The neurophysiological correlates of inhibition and impulse control problems.

3.3.1. Manifestations of inhibition problems in children¶

• Frequently blurts out answers before the question is finished (DSM IV/5)
• Frequently interrupts and disturbs others (e.g., bursts into others’ conversations or games) (DSM IV/5)
• Has difficulty waiting for his/her turn (DSM IV/5)
  Having difficulty waiting for one’s turn is not only an impulsivity problem, but also a problem of aversion to inactivity.

3.3.2. Manifestations of inhibition problems in adults¶

• Spontaneous, rash decisions
  This is one of the 9 most accurate symptoms of ADHD in adults, but²² is also found in acute (hypo)manic sufferers or some Axis II problems.
  • Spontaneous purchases
    • Buy something without needing it
    • Buy something without reflection whether the money is enough for it
  • spontaneous acceptance / termination of a job
  • spontaneous beginning / spontaneous termination of a relationship
  • Unconcern in dangerous situations Whether this is really an inhibition problem or rather a question of attention control is an open question. In ADHD, according to this understanding, the directing of attention follows the dictates of the stress maxim that there is a (survival) threatening, uncontrollable danger. This can lead to significantly different judgments about what is dangerous and what is not.
• Exuberant ideas need to be communicated quickly before they are in danger of being forgotten²³
• Excessive cell phone use correlated with impulsivity²⁴ and affected 20.1% of participating student subjects.
  • Excessive cell phone use further correlated with higher levels of
    • Alcohol consumption
    • Sexual activity
    • PTSD/PTBS
    • Anxiety disorders
    • Depression
• Impulsivity in ADHD and elevated BMI share genetic and neurophysiological correlates²⁵
• Speech is often experienced as aggressive by the environment

Impulsivity alone is not a compelling indicator of ADHD. In a study of impulsive subjects with and without ADHD, ADHD subjects showed a greater lack of interpersonal interaction, more indecisive decision-making, and lower motor skills than the non-ADHD subjects with and without impulsivity. Impulsivity without ADHD showed good motor skills, good 1:1 social interactions, good decision making in spatial orientation tasks, and more versatile laterality in the lower limbs.²⁶

3.4. Impulse control problems as symptoms of stress¶

Typical stress symptoms are known to be:

• Impulsivity²⁷
• Riskier decisions²⁸
• Decision-making problems²⁷²⁹³⁰

3.5. Increased willingness to take risks¶

3.5.1. Increased risk-taking as an ADHD symptom¶

Studies report significantly increased risk behaviors in ADHD sufferers.³¹³²
An extensive study of 2,434 workers in Iran found a risk distribution of:

• Very low risk (65.6 %)
• Low risk (27.8 %)
• Moderate risk (4.1 %)
• High risk (2.5 %)

ADHD increased the probability of belonging to the moderate- or high-risk behavior group by 3.4 and 3.1-fold, respectively. Anxiety disorder increased the risk by 2.1 and 2-fold, respectively, compared to the probability of belonging to the lowest risk group.³³

According to other sources, there is no firm evidence that ADHD sufferers are at increased risk.³⁴³⁵

We see increased risk behaviors especially in externalizing ADHD subtypes.

Some ADHD sufferers like to engage in high-risk sports (hang gliding, bungee jumping, motocross, mountain biking).²³ It is possible that the concentration required for this or triggered by it could act like a hyperfocus
Increased risk-taking seems to correlate with spontaneous and impulsive decisions. However, the above-mentioned increased risk-taking of people with anxiety disorders could argue against this.

Increased risk-taking in ADHD is in tension with anxiety, which is often increased in ADHD. The (medically not validated) data of the ADxS.org symptom test showed a correlation of the answers to the question “Do you often make riskier decisions?” mainly with impulsivity (0.35), novelty seeking (0.34) as well as hyperactivity (0.26), but less so with inner restlessness or attention problems (0.19 each), while there was no correlation at all with the symptom anxiety (0.01) (as of January 2023, n = 19,000).

3.5.2. Increased risk taking as a symptom of stress¶

Increased risk-taking is a symptom of stress.³⁶ This increased risk-taking ended 40 to 80 minutes after the end of the stressful situation and then decreased even below the level of non-stressed subjects.³⁷

Increased risk-taking is thought to be a symptom of stress in people who show a robust cortisol elevation to an acute stressor. Young men without a marked cortisol response to a stressor did not show increased risk-taking. This may be interpreted to mean that the stress response of risk-taking elevation occurs only in those individuals who respond to stress with a cortisol elevation, or to mean that the subjects who did not have a cortisol elevation measured to the TSST did not respond to it with stress.³⁸

3.6. Novelty Seeking / Sensation Seeking¶

Novelty Seeking (Cloninger) is a psychological construct within a concept for personality diagnostics, whereas Sensation-Seeking (Zuckerman) is a physiological construct. The terms are sometimes used (incorrectly) interchangeably. Whether the constructs describe different phenomena is an open question. Neurophysiological data suggest a match.³⁹⁴⁰

Novelty Seeking is together with

• Harm Avoidance and
• Reward Dependence

Part of a concept for describing personalities and personality disorders.⁴¹

Sensation Seeking is defined as⁴²

• Search for
  • Diverse, novel, complex and intense sensations and experiences
• Willingness to
  • Physical, social, legal and financial risks around such experiences

Sensation Seeking consists of 4 subconstructs with different affinities:⁴³

• Thrill and adventure seeking (TAS)
  • Physically risky activities
• Experience seeking (ES)
  • New experiences, personal development, unconventional lifestyle (travel, music, drugs, self-awareness, foreign cultures, cognitive, sensory or emotional stimulation)
• Disinhibition seeking (DIS)
  • Variety through social stimulation (partying, promiscuity, social drinking).
  • Disinhibition = literally: disinhibition
• Boredom susceptibility, (BS)
  • Aversion to routine and boredom
    and
  • Tendency to restlessness when the environment no longer offers variety
  • Boredom susceptibility = literally, susceptibility to boredom

Novelty seeking is reported to be linked to impulsivity. According to data from the (medically unvalidated) ADxS.org online symptom test (as of January 2023, n = 19,000), Novelty Seeking correlated most strongly with Impulsivity (0.27) and Inner Restlessness (0.25), and significantly more strongly with the externalizing ADHD subtypes (0.28) than with ADHD-I (0.04)
This is consistent with the results of other studies.⁴⁴⁴⁵

Novelty Seeking could also be typical for sufferers who have low arousal or need higher arousal for optimal performance.
This connection could also be explained conclusively with the approach described under “Inner emptiness”: Strong new stimuli are needed for the reward center to kick in and interest in something to be aroused. The dysphoria that results from cortical inactivity due to the resulting drop in dopamine levels is perceived as unpleasant and should be avoided. Intense new stimuli and high risks lead to a kind of volitionally induced hyperfocus.
We know quite a few sufferers who avoid their dysphoria when inactive by always staying active, e.g. preferring an active vacation to a “lazy” beach vacation.

Reward discounting is said to arise only with conditioned stimuli because a conditioned outcome expectancy is required. With novel stimuli, the unpleasant disinterest that arises from reward discounting would not be possible.

Novelty seeking is associated with the DRD4-7R gene variant, which is a candidate gene for ADHD.