3. Impulsivity / inhibition problems with ADHD

Author: Ulrich Brennecke
Review: Dipl.-Psych. Waldemar Zdero

Impulsivity is a complex construct and includes risky behavior in relation to rewards, inappropriate and premature reactions and an impairment of response inhibition.¹ Excessive impulsivity is also referred to as a disorder of impulse control (inhibition). Impulsivity has advantages in certain life situations where quick focus and quick decisions are required² or when gathering resources³ and appears to be primarily dopaminergic⁴, but also noradrenergic¹ controlled.

Impulsivity problems in ADHD affect ADHD-HI and ADHD-C in particular, and ADHD-I to a lesser extent.
Impulsivity is divided into action impulsivity and decision impulsivity (choice impulsivity).⁵
Action impulsivity is characterized by spontaneous, immediate action without forethought and a lack of inhibition of reactions. Symptoms include excessive talking, blurting out, not being able to wait and interrupting.
Choice impulsivity (Temporal Reward Discounting) involves the devaluation of distant rewards and the preference for small, immediate rewards as well as the inability to postpone reinforcement and reward. This form of impulsivity occurs not only in ADHD but also in other disorders and correlates with problems in decision making and delay aversion.

In children, impulse control problems or inhibition problems are manifested by interrupting, bursting out and difficulties waiting. In adults, they manifest themselves through spontaneous decisions, recklessness in dangerous situations or excessive cell phone use. Impulsivity is one of the main symptoms of ADHD, but is not conclusive evidence of ADHD and can also occur in other disorders.

Impulsivity is a symptom that also occurs with other mental health problems⁶
Impulse control problems are also symptoms of stress and manifest themselves in impulsivity, riskier decisions and problems with decision making. People with ADHD often exhibit increased risk-taking behaviors, especially those with externalizing symptoms. This can be seen in a preference for risky sports.
Increased risk-taking is both an ADHD symptom and a stress symptom. It correlates with impulsivity and hyperactivity, but not with anxiety. The increased willingness to take risks usually ends again after a stressful situation.

Novelty seeking and sensation seeking are similar psychological constructs that describe the search for new and exciting experiences.
Novelty Seeking is associated with Harm Avoidance and Reward Dependence, Sensation Seeking consists of the sub-constructs Thrill and adventure seeking, Experience seeking, Disinhibition seeking and Boredom susceptibility.
Both correlate with ADHD-HI and ADHD-C and are associated with stress, depression and other mental disorders.
Novelty seeking may be associated with low arousal and the DRD4-7R gene variant. People with Novelty Seeking may need more intense stimuli to feel interest and motivation. Risky behavior, such as drug use or promiscuous behavior, may be an expression of sensation seeking. The response to reward delays may be impaired in people with Novelty Seeking.

• 3. Impulsivity / inhibition problems
  • 3.1. 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
    • 3.3.2. Impulse control disorder as an extreme form
  • 3.4. Impulse control problems as symptoms of stress
  • 3.5. Increased willingness to take risks
    • 3.5.1. Increased willingness to take risks as an ADHD symptom
    • 3.5.2. Increased willingness to take risks as a symptom of stress
  • 3.6. Novelty Seeking / Sensation Seeking

3. Impulsivity / inhibition problems¶

Impulsivity is divided into:⁷

• rapid reaction impulsivity / action impulsivity (AI)⁸
• cognitive / choice impulsivity (CI)⁹

Inhibition problems are primarily attributed to ADHD-HI and ADHD-C.¹⁰ This also applies to elective impulsivity.¹¹
Impulsivity usually results from inhibition problems. Inhibition problems often manifest themselves, but not only through impulsivity problems.

An impulse control disorder is an impulse problems are control problems occur in

3.1. Action impulsivity (AI)¶

Action impulsivity manifests itself as:

• Tendency to act immediately, with diminished foresight and no connection to the current demands of the environment
  • a reduced ability to inhibit prepotent reactions
  • a failure of voluntary motor inhibition or disinhibition (inhibition)
• Consequences of a problem with self-regulation and thus inhibition.¹²¹³ Inhibition is the ability to inhibit (suppress) or control an impulsive (automatic) reaction and instead act in a way that is appropriate to the situation.

Symptoms of action impulsivity in ADHD are:¹⁴

• Excessive speaking
• Bursting out
• Can’t wait until it’s your turn
• Interrupt

Impulsivity is something different from an emotional outburst.
Affective outbursts 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 with ADHD is aware that they have made a decision.¹⁵ Even 200 milliseconds before execution, the person can cancel the decision that has already been made.¹⁶
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, the prevention of a decision option.
Figuratively speaking, one area of the brain puts decisions “up for discussion” and gives other areas of the brain the opportunity to assess them and then approve or reject them.

This checking and canceling mechanism is essentially controlled by dopamine. If the dopamine control circuit is disrupted, the mechanism used to abort decisions is impaired. Disorder of inhibition is conceivable, for example, if the dopamine level is too low or too high, so that the signal transmission is too weak or noisy, so that the attenuating (inhibitory) impulse does not arrive.
The known disorder 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 deal with it further in the Motivation chapter for the time being.

Temporal reward discounting is included:

• Devaluation of more distant rewards, while immediate rewards remain unchanged^171813192021
  • Preference for immediate (small) rewards over more distant larger ones
  • Impaired ability to postpone reinforcement and reward
  • Devaluation of more distant rewards
  • All three forms are symptoms that occur not only in ADHD, but also in other disorders such as addiction or severe depression.²²
  • overlaps conceptually with
    • Impairment of decision-making
    • Delay aversion (temporal discounting, delay discounting, delay aversion). Delay discounting is the phenomenon in which a delayed outcome of a choice reduces the subjective value of a reward and reflects the operative measure of decision impulsivity.²³²⁴

Immediate reward and delayed reward are represented by different brain systems:²⁵

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

A devaluation of delayed rewards is not only found in ADHD, but also in²⁶

• Addictive behavior (heroin addiction], cocaine addiction, alcohol addiction, opioid addiction, nicotine addiction),
• Bipolar Disorder
• Antisocial personality disorder
• Social anxiety disorder
• Borderline personality disorder
• Major depressive disorder
• Schizophrenia
• Schizoaffective disorders
• Pathological gambling
• Lesions of the orbitofrontal cortex

Impulsivity appears to result from the avoidance of negative affective states associated with delay. People with ADHD 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 (personally desired events).²⁷

ADHD appears to be related to suboptimal temporal 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.²⁸

The discounting of temporal rewards was more pronounced in people with ADHD-C than in ADHD-I or controls. However, the negative emotions related to waiting were equally strong. Thus, the choice of smaller but more readily available rewards was not determined by a stronger aversion to waiting, but by reduced inhibition. In other words, the choices in the person with ADHD-C were more in line with their feelings.²⁹

Delay aversion and the preference for quicker and smaller rewards in ADHD is completely normalized by access to immediate visual stimuli during the waiting period.³⁰

Dopaminergic drugs, especially those targeting DRD2 and DRD3, correlated with an increased preference for later rewards. Testosterone and cortisol led (in the short term) to more impulsive decisions.i²⁶

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¶

• Often blurts out answers before the question is finished (DSM IV/5)
• Frequently interrupts and disturbs others (e.g. bursts into other people’s conversations or games) (DSM IV/5)
• Finds it difficult to wait his/her turn (DSM IV/5)
  Having difficulty waiting for one’s turn is not only seen as an impulsivity problem, but also as 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, but³¹ is also found in acute (hypo)manic people with ADHD or some Axis II problems.
  • Spontaneous purchases
    • Buying something without needing it
    • Buying something without reflecting on whether there is enough money for it
  • spontaneous acceptance / termination of a job
  • spontaneous beginning / spontaneous ending of a relationship
  • Unconcern in dangerous situations Whether this is actually an inhibition problem or rather a question of directing attention is an open question. In ADHD, according to this understanding, the control of attention follows the dictates of the stress maxim that there is a (survival) threatening, uncontrollable danger. This can lead to significantly different assessments of what is dangerous and what is not.
• Exuberant ideas must be communicated quickly before they are in danger of being forgotten³²
• Excessive cell phone use correlates with impulsivity³³ and affected 20.1% of the participating student test subjects.
  • Excessive cell phone use continued to correlate with higher levels of
    • Alcohol consumption
    • Sexual activity
    • PTSD/PTBS
    • Anxiety disorders
    • Depression
• Impulsivity in ADHD and increased BMI share genetic and neurophysiological correlates³⁴
• Speech is often perceived as aggressive by the environment

Impulsivity alone is not a compelling indication of ADHD. In a study of impulsive subjects with and without ADHD, people with ADHD 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.³⁵

3.3.2. Impulse control disorder as an extreme form¶

Impulse control disorder is a specific form of impulse problems. It is an independent psychiatric condition characterized by compulsive, impulsive behavior with impaired self-control.
The prevalence of impulse control disorder is 6.1%. People with ADHD have a prevalence of 19.6%, which is around 3.2 times higher.³⁶
People with ADHD are unable to resist their impulses. The decision to carry out the impulse action is made unconsciously. Impulse control disorders are typically subject to 5 phases:

• Impulse
• Growing tension
• Trading with pleasure
• Liberation from the urge
• Feelings of guilt (not mandatory)

Examples are mentioned:³⁷

• Gambling addiction (pathological gambling)
• Trichotillomania (pathological hair plucking)
• Kleptomania (pathological stealing)
• Pyromania (pathological arson)
• Intermittent explosive disorder (pathological irascibility)
• Hypersexuality
• Compulsory purchase
• Internet addiction
• Skin Picking Disorder

3.4. Impulse control problems as symptoms of stress¶

Impulsiveness can also be seen as an urgency to make decisions¹

Typical stress symptoms are known:

• Impulsiveness³⁸
• Riskier decisions³⁹
• Decision-making problems³⁸⁴⁰⁴¹

3.5. Increased willingness to take risks¶

3.5.1. Increased willingness to take risks as an ADHD symptom¶

Studies⁴²⁴³ such as meta-analysis studies⁴⁴ report a significantly increased risk behavior of people with ADHD.
A comprehensive 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 times, respectively. An anxiety disorder increased the risk behavior by 2.1 and 2 times, respectively, compared to the probability of belonging to the lowest risk group.⁴⁵

According to other sources, there is no reliable evidence that people with ADHD are at increased risk.⁴⁶⁴⁷

We see increased risk behaviors, especially in externalizing ADHD subtypes.

Some people with ADHD enjoy high-risk sports (hang-gliding, bungee jumping, motocross, mountain biking).³² It is possible that the concentration required for this or triggered by it could act like a hyperfocus
An increased willingness to take risks appears to correlate with spontaneous and impulsive decisions. However, the above-mentioned increased willingness to take risks in people with anxiety disorders could speak against this.

Increased risk-taking in ADHD is in tension with increased anxiety that is common in ADHD. These could be different forms of presentation.
The data from the (medically unvalidated) ADxS.org symptom test showed that the answers to the question “Do you often make riskier decisions?” correlated primarily with impulsivity (0.35), novelty seeking (0.34) and hyperactivity (0.26), but less so with inner restlessness or attention problems (0.19 in each case), while there was no correlation with the symptom anxiety (0.01) (as at January 2023, n = 19,000).

3.5.2. Increased willingness to take risks as a symptom of stress¶

Increased willingness to take risks can be a stress symptom of acute, short-term stress.⁴⁸ This increased willingness to take risks ended 40 to 80 minutes after the end of the stressful situation and then even decreased below the level of non-stressed persons.⁴⁹
This is in line with findings that chronic stress contributes to a reduction in the willingness to take risks.

An increased willingness to take risks is said to be a stress symptom in people who show a robust cortisol increase in response to an acute stressor. Young men without a clear cortisol response to a stressor did not show an increased willingness to take risks. This can be interpreted to mean that the stress response of increased risk-taking only occurs in those people who respond to stress with an increase in cortisol, or that the subjects in whom no increase in cortisol was measured in response to the TSST did not respond to it with stress.⁵⁰

3.6. Novelty Seeking / Sensation Seeking¶

Novelty seeking (Cloninger) is a psychological construct within a concept for personality diagnostics, while sensation seeking (Zuckerman) is a physiological construct. The terms are sometimes (incorrectly) used synonymously. Whether the constructs describe different phenomena is an open question. Neurophysiological data suggest that there is agreement.⁵¹⁵²

Novelty Seeking is together with

• Harm avoidance and
• Reward Dependence

Part of a concept for describing personalities and personality disorders.⁵³

Sensation seeking is defined as⁵⁴

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

Sensation Seeking consists of 4 sub-constructs with different affinities:⁵⁵

• Thrill and adventure seeking (TAS)
  • Physically risky activities
• Experience seeking (ES)
  • New experiences and adventures, 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 any variety
  • Boredom susceptibility = literally: susceptibility to boredom

Novelty seeking is said to be linked to impulsivity. According to the 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.⁵⁶⁵⁷

Novelty seeking could also be typical for people with ADHD who have low arousal or require higher arousal for optimal performance.
This connection can also be conclusively explained using the approach described under “Inner emptiness”: It takes strong new stimuli to trigger the reward center and arouse interest in something. The dysphoria caused by 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 deliberately induced hyperfocus.
We know quite a few people with ADHD who avoid their dysphoria when inactive by always staying active, e.g. preferring an active vacation to a “lazy” beach vacation.

Reward discounting should only occur with conditioned stimuli, as a conditioned expectation of results is required. With new stimuli, the unpleasant disinterest that arises from the reward delay would not be possible.

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