Impulse control disorders
Impulse control disorders (ICDs) are a group of psychiatric disorders characterized by a failure to resist an impulse, drive or temptation to perform an act that is harmful to the individual or to others. Examples of ICDs are pathologic gambling, hypersexuality, compulsive shopping and compulsive eating.
How common are the ICDs?
ICDs are increasingly recognized as psychiatric complications of Parkinson’s. In a study, the lifetime prevalence of ICDs (pathologic gambling, hypersexuality or compulsive shopping) was 6.1%, and 13.7% in any patient on dopamine agonists (Voon V, 2006). Thus, ICDs are not uncommon in Parkinson’s.
As these behavioural disorders are embarrassing, many Parkinson’s patients may not report such problems to the doctors. Some patients may not even admit to have ICDs despite direct questioning by the doctors. Thus, it is highly likely that ICDs are under-recognized.
ICDs and dopamine agonists
ICDs have been reported in association with levodopa treatment (Molina JA, 2000). But overall, the most commonly implicated Parkinson’s medications in ICDs are dopamine agonists (Voon V, 2006) such as Pramipexole and Ropinirole. However, it has not been confirmed whether any dopamine agonist has a higher risk of causing ICDs compared with other medications from the same category. The symptoms of ICDs generally start within a few months following the initiation of treatment or an increase in the dose of medication.
With the increasing use of dopamine agonists in the treatment of Parkinson’s, it is advisable to warn the patients of the possibility of ICDs when they are receiving these medications. If left untreated, ICDs obviously result in significant social and mental disability.
What are the risk factors for ICDs?
The risk factors for ICDs remain unclear. Studies have shown that younger age and history of ICDs prior to the onset of Parkinson’s were associated with higher risk of developing ICDs.
Is there sexual predilection for ICDs?
In general, both men and women can develop the various types of ICDs. However, hypersexuality is more common in men (Voon V, 2006).
In an interesting report, twelve Parkinson’s patients were found to have pathologic gambling (Molina JA, 2000). In most of these patients, gambling started following levodopa treatment, and occurred either exclusively or predominantly during the “on” periods. The gambling methods include slot machine, scratch cards, Internet sites and betting on sports or animal racing.
Even since the discovery of levodopa in the 1960’s, it had been known that this medication could increase sexual drive. Some Parkinson’s patients may even successfully resume their sexual activities following treatment with levodopa. Interestingly, there have been reports of levodopa-treated Parkinson’s patients who regained penile erection despite being impotent for many years prior to the diagnosis of Parkinson’s.
In extreme cases, levodopa (Uitti RJ, 1989) and dopamine agonists can result in hypersexuality, a condition in which the sexual thoughts or behaviours are excessive or atypical compared with the pre-existing status. Hypersexuality manifests as preoccupation with sexual thoughts, excessively requesting sex from partner or spouse, promiscuity, uncontrollable masturbation, calls to telephone sex lines and pornography. Most remarkably, hypersexuality can even occur in those who suffer from erectile dysfunction (impotence), as illustrated in the following article (“rejuvenated sex life”).
In this condition, there is preoccupation with buying or shopping that is described as irresistible urge. Patients often experience increasing anxiety which is relieved by purchasing items. Patients who have compulsive shopping tend to excessively and unnecessarily spend money on buying items. Obviously, this results in severe financial loss.
The eating habit of these patients is excessive, i.e. eating when they are not hungry and to the extent of gaining significant weight. Craving for sweet food has been reported in Parkinson’s.
Treatment of ICDs
First of all, it is important to provide health education to the Parkinson’s patients and caregivers, especially the role of Parkinson’s medications in the causation of ICDs. In cases of pathological gambling and compulsive shopping, family members can help by controlling the access to money, e.g. taking over the credit card or bank accounts from the affected patients.
Reducing the daily dose of dopamine agonist can help in treating the ICDs (Ferrara JM, 2008). Sometimes, the dopamine agonists may even need to be stopped. If this results in significant worsening of the movement disorder, it is advisable to replace dopamine agonist with levodopa, as the latter appears to be the less likely to cause ICDs (Voon V, 2006).
In severe cases of ICDs, the combined effort of brain specialist and psychiatrist is certainly needed.
· ICDs are not uncommon in Parkinson’s – the lifetime prevalence of ICDs (pathologic gambling, hypersexuality or compulsive shopping) is 6.1%
· Dopamine agonists are the most commonly implicated Parkinson’s medication in the causation of ICDs
· Due to its devastating impact, Parkinson’s patients and caregivers should be educated on the risk of ICDs, especially when patients are taking dopamine agonists
· In the treatment of ICDs, modification of medications is needed, such as reduction in the dose of dopamine agonist. In severe cases, the psychiatrists should be consulted.
Ferrara JM, Stacy M. Impulse control disorders in Parkinson’s disease. CNS Spectr 2008; 13(8): 690-698.
Molina JA, Sainz-Artiga MJ, Fraile A, et al. Pathologic gambling in Parkinson’s disease: a behavioural manifestation of pharmacologic treatment? Mov Disord 2000; 15(5): 869-872.
Voon V, Hassan K, Zurowski M, et al. Prevalence of repetitive and reward-seeking behaviours in Parkinson’s disease. Neurology 2006; 67: 1254-1257.