Impulsive and compulsive behaviour

Impulsive behaviour is when someone can’t resist the urge to carry out an activity - often one that gives instant reward or pleasure. They’ll quickly act on this urge without thinking about the possible negative impacts it might cause to themselves or those around them. For example, buying something expensive that they can’t afford.

In compulsive behaviour, a person has a strong urge to act in a certain way, often repeatedly. They’ll often carry out this behaviour to help reduce the worry or tension they get from their urge. For example, eating large amounts of food even when they’re not hungry.

  • Pathalogical gambling 

    This is when someone can’t resist the impulse to gamble, even though it may cause money problems or harm their relationships with loved ones. Some people might even steal money to gamble, or to pay for an expensive lifestyle.

    There are different ways to gamble, such as using betting shops, placing bets online, or using mobile phone apps. If someone uses their phone to gamble, it may not always be obvious that they’re doing it.

    Hypersexuality


    This is when a person experiences compulsive or uncontrolled sexual thoughts, urges or behaviours that are out of character, difficult to resist, or harmful to themselves or others. This may include excessive use of pornography, compulsive masturbation, repeated use of sex workers or paid sexual services, risky sexual behaviour, secret relationships, inappropriate sexual behaviour, or sexual activity that places the individual or others in emotionally, financially, socially or physically vulnerable situations.

    In some cases, hypersexuality associated with dopamine agonist medications has been linked to relationship breakdown, severe financial consequences, safeguarding concerns, criminal behaviour, or situations in which vulnerable individuals have themselves been exposed to exploitation, coercion or sexual harm. People experiencing hypersexuality may not fully recognise the change in their behaviour at the time it is occurring.

    Binge eating

    This is when someone eats a lot of food in a short period of time, and isn’t able to stop, even when they may feel full.

    They may feel depressed or guilty about the amount of food they’re eating. They may also eat alone or secretly at night because they feel embarrassed.

    Obsessive shopping

    Some people may become obsessed with buying things from shops or online. They’ll get an urge that they can’t control to buy more than they need or can afford. This can lead to issues with money. It can also impact someone’s mental health.

    Punding 

    This is when someone repeatedly carries out an activity that has no goal or purpose. This usually includes handling and sorting objects. The person may be fascinated with taking electronic equipment apart or collecting a type of object, for example. People may stay up all night to carry out this behaviour, which can affect sleep. It can also cause social problems with family or at work.

    Punding can also seriously affect someone’s finances. For example, they might have to replace or repair electronic items they’ve taken apart.

    Some people also carry out other behaviours with no purpose, such as compulsive smoking, driving or walking, or using the internet too much.

    Hobbyism 

    This is when someone has the uncontrollable urge to carry out a hobby, such as gardening, using the internet or doing crafts.

    Hobbies are usually healthy habits that people enjoy in their spare time. But in hobbyism, someone will spend an unusually long amount of time focusing on an activity or interest. This can negatively impact their personal life. For example, someone might be so fixated on their hobby, they repeatedly miss meals that they would usually have with their family.

Impulse Control Disorder (ICD)

Impulsive and compulsive behaviours that are more severe are often called ‘impulse control disorders’. Three distinguishing factors of a disorder include:

  1. Loss of Control: Urges become increasingly difficult to resist, and the person feels unable to stop or delay the behaviour even when they recognise the negative consequences.

  2. Significant impairment or distress: The behaviour begins to interfere with important areas of life such as relationships, work, finances, health, or emotional wellbeing.

  3. Persistence or repetition: The behaviour occurs repeatedly over time rather than as an isolated incident, and often continues despite repeated attempts to reduce or stop it.

Impact of shame and stigma

Many people experiencing impulse control disorders also experience feelings of shame, guilt, or embarrassment about their behaviour, particularly when it affects relationships, finances, work, or self-esteem. Some behaviours associated with these disorders - such as gambling or compulsive sexual behaviour - still carry significant social stigma, as does mental illness more generally, sometimes more so for older generations.

In addition, these behaviours are often misunderstood as simply a lack of willpower or “bad choices.” It is easy to take for granted our ability to assess, filter, and reject the thousands of thoughts and impulses that pass through our minds each day. It can be difficult to imagine and understand what it is like to lose that control.

Because of this, many individuals hide their struggles from loved ones, friends, or healthcare professionals out of fear of judgement. This shame can increase isolation and emotional distress, and in some cases may reinforce the cycle of impulsive or compulsive behaviour. Understanding these behaviours as mental health conditions - rather than moral failings - can help reduce stigma and encourage people to seek appropriate support and treatment.

How common are ICDs as side-effects of dopamine-agonists

For dopamine agonists use in Parkinson's Disease, Parkinson’s UK cites the prevalence of impulse control disorders (ICDs) as between 3.5% and 43%. This is based on a 2021 narrative review by Z Zhang et al.

However, this headline range compares studies that differ in two fundamental ways.

  1. How hard they look: The estimated prevelance of ICD is highly sensitive to the method of data collection. Dopamine agonists can cause behaviours associated with considerable shame and secrecy, and can also impair insight.

  2. How long they look for: The review compares cross-sectional studies that measure ICD at a single point in time with longitudinal studies that track patients over several years.

The apparent variation in prevalence is therefore not simply a reflection of uncertainty about the condition itself, but in differences in study methodology.

As methods of detection have improved, studies have generally identified substantially higher rates of ICDs. Early clinical trials often relied heavily on self-reporting and identified relatively few cases. More recent studies using active screening and longer follow-up have consistently produced higher estimates.

The largest cross-sectional study to date—the DOMINION study (2010), involving more than 3,000 Parkinson's patients—found that 17.1% of dopamine agonist users had an active ICD at the time of assessment (approximately one in six). However, this figure is sometimes incorrectly interpreted as meaning that only one in six patients will ever develop an ICD during treatment.

By contrast, the longitudinal study by Corvol et al. (2018) found that 51.5% of patients exposed to dopamine agonists experienced an ICD over a five-year period. This does not contradict the DOMINION study; rather, it reflects the cumulative risk of developing an ICD over time.

For Restless Legs Syndrome, there is less research. However, NICE reports that studies vary from 6-17%.

Unfortunately, the wide variation in published estimates may have resulted in some patient information leaflets classifying impulsive and compulsive behaviours as having a "frequency not known." We are concerned that this terminology may be interpreted by patients as meaning that the risk is either negligible or rare. By constrast, if a frequency above just 10% was accepted as a consensus, it would fall within the regulatory definition of 'very common'. This raises the question of whether current frequency classifications continue to reflect the contemporary evidence base.

One of DAAG's objectives is to advocate for a comprehensive review of the evidence base, including closer examination of studies that may underestimate the true frequency of ICDs because their methodology did not adequately account for the effects of shame, stigma, impaired insight, or limited duration of follow-up.

Who is most likely to be affected?

Impulse control disorders affect people of all ages, backgrounds, personalities, and life histories.

Some studies have proposed “risk factors” or groups of people thought to be more likely to experience impulse control disorders, including people of younger age, male sex, history of depression or anxiety, smoking, or other addictive behaviours.

However, other researchers have questioned how reliable these associations are. Because shame, stigma, impaired insight, and willingness to disclose symptoms can vary significantly between different groups of people, they argue the likelihood of reporting or recognising impulsive behaviour does not necessarily correspond to the likelihood of experiencing it.

Critically, the communication of poorly evidenced and potentially incorrect “risk factors” may create false assurance in patients who do not identify with those groups - and even their healthcare professionals (e.g., patients told “you don’t need to worry because you are an older woman”). In behavioural science, this relates to concepts such as optimism bias and normalcy bias: natural cognitive tendencies that lead people to believe negative outcomes are more likely to happen to other people, particularly when the risk feels unfamiliar, frightening, or difficult to imagine. As humans, we are psychologically inclined to favour information that makes us feel safe.

We consider it urgent for the research on these risk factors to be scrutinised as part of a wider evidence review.

What happens when dopamine agonists are reduced or stopped?

Many patients experience significant improvement in impulsive or compulsive behaviours after reducing or discontinuing dopamine agonist treatment. However, recovery is not always immediate and some behaviours, urges or consequences may persist after the medication has been stopped. Published evidence suggests this may be more likely in people exposed to higher doses, longer treatment durations, or those who have experienced more severe impulse control disorders.

Reducing or discontinuing dopamine agonists can also be complex and should usually be undertaken gradually and under medical supervision. Some patients experience withdrawal symptoms, known as Dopamine Agonist Withdrawal Syndrome (DAWS).

Dopamine Dysregulation Syndrome

Impulsive or compulsive behaviour associated with dopamine agonists may also manifest in the compulsive or addictive use of the medication itself. Some patients may feel a strong urge to take higher doses than prescribed or experience significant difficulty reducing, tapering or stopping the medication. This may relate to compulsive behaviour centred on medication use, dependence on the way the medication makes them feel, worsening withdrawal symptoms, or fear of the return of underlying health symptoms. This is known as dopamine dysregulation syndrome (DDS).

A person experiencing DDS may resist attempts to reduce their medication, believe they require increasingly higher doses, or in some cases secretly hoard or conceal medication in order to take more than prescribed. Because insight and self-recognition may be impaired, patients are not always aware that their medication use has become problematic. For this reason, family members or carers may sometimes recognise concerning patterns before the patient themselves.