Impulse Control Disorders (ICDs) are a well-recognised side effect of medical treatment of Parkinson’s disease, and include a variety of hedonistic or pleasure-seeking behavioural disorders including pathologic gambling, compulsive shopping and eating, hypersexuality and hobbyism.
ICD severity can vary substantially. At the mild end of the spectrum, patients may experience an exacerbation of a pre-existing behaviour or personality trait, for example someone who has a tendency to hoard, might find it a bit more difficult to throw things out. At the severe end, ICDs can cause financial and relationship havoc. Fortunately, we are starting to better understand ICDs, how to avoid them and how to help with de-escalation when they do occur.
Risk factors for ICDs
Studies have found that ICDs are more common in patients of younger age, those who live on their own, and patients who have a high caffeine intake. ICDs tend to progress faster in men.
ICDs can be a side effect of any of the medications that supplement or stimulate dopamine in the brain. The biggest risk factor for ICD development is treatment with a class of medications known as dopamine agonists. Formulations available in Australia include rotigotine (Neupro), pramipexole (Sifrol) and ropinirole (Repreve). These medications can be used alone in the treatment of Parkinson’s disease or in combination with other anti-Parkinsonian medications.
How common are ICDs?
A study published in the journal Neurology this year by Corvol and others (link abstract) followed a relatively large group of French patients with early stage Parkinson’s disease over 5 years. The key finding was that dopamine agonist use was associated with a cumulative increase in the development of ICDs. 45% of patients in the study who were treated with dopamine agonist therapy developed an ICD over 5 years. The higher the dose, and the longer the duration of treatment, the higher the risk of ICD development.
Dopamine agonist treatment is not of course, all bad. Indeed dopamine agonists can be an important part of a treatment regime for PD. They can be particularly effective for symptoms such as restless legs, dream enactment behaviour and can improve mood. Further, they can be helpful in reducing symptom variability through the day in those patients that have developed motor fluctuations or dyskinesias.
Can ICDs improve or resolve?
The good news is that ICDs can improve and do resolve completely in some patients. Corvol et al found that 50% of the ICDs that developed on dopamine agonist therapy had resolved one year after stopping the inciting medication.
Prevention and management of ICDs
Keeping medication dose low and maintaining open and frank discussions about changes in behaviour are key in the prevention and management of ICDs.
Dopamine agonists may take weeks to become effective. Waiting for benefit can be difficult, but patience can be very important in optimising dopamine agonist treatment – keeping the dose low helps to reduce the risk of ICD development.
Talking about ICDs can be very challenging! Some patients feel embarrassed or ashamed of their ICD, others may be in denial or lack insight. Partners & carers can be important in bringing ICDs to light. Fortunately ICDs are treatable and do get better with alterations in therapy in the majority of patients. Talking about them is the first step in achieving improvement.
Integrated Neurology www.integratedneurology.com.au
Sydney North Neurosurgery www.snns.com.au
Corvol et al. Longitudinal analysis of impulse control disorders in Parkinson’s disease. Neurology 2018.
Boylan & Kostic. Don’t ask, don’t tell. Impulse control disorders in PD. Neurology 2018.
The information provided in this article is of a general nature only and is not treatment advice. Recommendations regarding therapy can only be made on a case by case basis, discussed between a patient and their treating doctor(s).
The information in this article was current at October 2018.