Sleep disorders are very common in Parkinson’s, occurring in 80-90% of patients. There are several reasons for these sleep disorders such as Parkinson’s itself, side effects of Parkinson’s medications and co-existing psychiatric disorders (especially depression).

The various types of sleep disorders in Parkinson’s are listed below (Friedman JH, 2008).

  - Insomnia
- Sleep fragmentation
- Excessive daytime sleepiness
- Restless leg syndrome
- Obstructive sleep apnea
- Vivid dreams
- REM-related behavioural disorder.

Insomnia

This is a common problem among Parkinson’s patients. Insomnia can be due to poorly controlled motor symptoms of Parkinson’s such as dyskinesia and body stiffness (as part of “wearing off” phenomenon). The former tend to occur in the evening in some Parkinson’s patients due to the accumulation of Parkinson’s medications in the body throughout the whole day (dyskinesia is commonly worsened by increasing dose of Parkinson’s medications – the peak-dose dyskinesia). The latter causes Parkinson’s patients to have difficulty turning their body when lying flat. Obviously, this results in insomnia as patients are unable to find the most comfortable sleeping position (many of us sleep better on our sides). 

Causes of insomnia		Treatment
Body stiffness and tremor		A dose of long acting levodopa (Sinemet CR or Madopar HBS) before sleep
Dyskinesia		Reduce the dose of Madopar or Sinemet before sleep
Selegiline		Take the second dose of Selegiline during lubch
Depression / anxiety		Anti-depressant and anti-anxiety medications

Selegiline, which causes increased level of alertness, can contribute to insomnia.

Treatment of insomnia: as outlined above.
Sleeping pills such as Lorazepam (Ativan) and Alprazolam (Xanax) are also helpful.  It has to be emphasized that in many Parkinson’s patients who complain of insomnia, the underlying cause is actually daytime napping due to sedentary life. Naturally, when we do not have much to do at home, we tend to feel sleepy. In these cases, patients are advised to keep themselves preoccupied with hobbies or physical exercise during daytime.  

Sleep fragmentation

This refers to frequent night-time awakening. Typically, patients start sleeping at the usual time. After about 2-3 hours, they wake up, feeling refreshed. Consequently, they have difficulty falling asleep again. 

Causes of sleep fragmentation		Treatment
Body stiffness as part of “wearing off” phenomenon		A dose of long acting levodopa (Sinemet CR or Madopar HBS) before sleep
Depression and anxiety		Anti-depressant and anti-anxiety medications
Restless leg syndrome		Dopamine agonist at bedtime
Nocturia (due to bladder overactivity)		Detrusitol

Excessive daytime sleepiness (EDS)

This is the result of many factors such as poor sleep quality (due to other types of sleep disorders in Parkinson’s such as insomnia, sleep fragmentation, vivid dreams or nightmares, Restless leg syndrome and Obstructive sleep apnea), Parkinson’s medications, coexisting depression and Parkinson’s itself.

EDS occurs in 15-50% of Parkinson’s patients. It is important to recognize and treat EDS because it can affect the quality of life in Parkinson’s. A major concern is the development of sleep attacks, which have been reported in 4-8% of Parkinson’s patients (the true prevalence is unknown).

Sleep attacks can occur without any warning or be preceded by excessive sleepiness. It typically strikes during inappropriate circumstances (when we usually do not expect it to happen) such as driving, talking and eating. Motor vehicle accidents due to falling asleep while driving have been known to occur (Frucht SJ, 1999). The risk factors for sleep attacks are both dopamine agonists and levodopa. The association between sleep attacks with dopamine agonists is not confined to any specific medications in this group of medications – Ropinirole, Pramipexole, Bromocriptine, Pergolide and Piribedil have been implicated. The issue of driving in Parkinson’s is further discussed in Chapter 20.    

Treatment of EDS: treat the underlying cause. In cases of sleep attacks, reducing the dose or discontinuing the implicated medication is beneficial. 

Restless leg syndrome (RLS)

RLS refers to a condition in which patients experience unpleasant sensations (burning, “insects crawling inside”, creeping) in the legs, especially when they are resting (sitting, lying in bed). There is also an uncontrollable urge to move in order to relieve these unpleasant sensations. As moving the legs relieves the discomfort, patients are constantly “shaking” their legs when sitting, pacing and “toss and turn” when in bed – thus explaining the term “restless leg”.    

RLS occurs in at least 20% of Parkinson’s patients. The symptoms of RLS are annoying and disabling because they cause insomnia and frequent awakening. As a result, many patients are exhausted and sleepy during daytime.

Treatment of RLS: Dopamine agonists such as Ropinirole and Pramipexole (Oertel WH, 2007).

Obstructive sleep apnea (OSA)

OSA is characterized obstruction to the airway during sleep which results in snoring and frequent night-time awakening (due to intermittent reduction of oxygen supply to the brain). The poor quality of sleep leads to excessive daytime sleepiness. It is uncertain whether OSA occurs more often in Parkinson’s patients than the general population. The long-term complications of OSA include hypertension, stroke and heart attack.
Treatment of OSA: Oxygen supply via facial mask during sleep.   

Vivid dreams or nightmares

About 30% of Parkinson’s patients experience vivid dreams or nightmares, which can be associated with Parkinson’s itself, the Parkinson’s medications (levodopa, dopamine agonists) and dementia. As mentioned previously, vivid dreams are different from hallucination, which occur during wakefulness.

In contrast to RMBD, there is no “acting out” of dreams in Parkinson’s patients who have vivid dreams or nightmares. Furthermore, vivid dreams or nightmares are usually reported by the Parkinson’s patients, while RMBD is usually reported by the bed partners. If frequent enough, vivid dreams or nightmares can disrupt sleep pattern and result in excessive daytime sleepiness.

 

Treatment of vivid dreams or nightmares: reduce the nighttime dose of Parkinson’s medications. If this is not possible (due to poorly controlled motor symptoms of Parkinson’s at night or in the early morning), anti-psychotic such as Quetiapine can be helpful.    

REM-related behavioural disorder (RMBD)

RMBD occurs in one-third of Parkinson’s patients, being more common in men. In 20% of Parkinson’s patients, RMBD precedes the motor symptoms. In contrast to vivid dreams, patients with RMBD physically “act out“ their dreams, in the form of verbalization (shouting, threatening) and abnormal body movement (jerking of legs or arms, violent assaults). Typically, the patients dream of “defending themselves from robbers or assailants” or “being chased”, and in the process of doing so, they unknowingly (and really) punch or kick their bed partners. Obviously, the spouses who are not aware of this disorder will chose to sleep separately from the Parkinson’s patients.

Treatment of RMBD: Clonazepam (Rivotril).

Role of the DBS surgery in sleep disorders

By improving the motor symptoms of Parkinson’s, the DBS surgery can improve the quality of sleep. However, this surgery has little or no effect on RMBD and RLS.  

Summary

  

References

Frucht SJ, Rogers JD, Greene PE, et al. Falling asleep at the wheel: motor vehicle mishaps in people taking pramipexole and ropinirole. Neurology 1999; 52: 1908-1910. Friedman JH, Millman RP. Sleep disturbances and Parkinson’s disease. CNS Spectr 2008; 13: 3 (Suppl 4): 12-17.Oertel WH, Trenkwalder CZucconi M, et al. State of the art in restless legs syndrome therapy: practice recommendations for treating restless legs syndrome. Mov Disord 2007; 22 Suppl 18: S466-75.   

The neglected pain of Parkinson’s

Introduction

Nowadays, the manifestations of Parkinson’s are known to be “two sides of the same brain” – they consist of both motor and non-motor symptoms. Parkinson’s is no longer known as only a movement disorder. Parkinson’s specialists have shifted their focus of attention to the commonly occurring non-motor symptoms such as constipation, depression and anxiety, which can even precede the motor symptoms of Parkinson’s by a few years. Towards the later stage of Parkinson’s, the non-motor symptoms can even be more disabling than the motor symptoms.

In the context of Parkinson’s, when one previously mentioned about pain, it usually referred to the emotional pain or mental agony due to the relentless progression of physical disability. However, the concept of pain in Parkinson’s has changed over the recent years due to the increasing recognition of a physical kind of pain, which is another example of the non-motor symptoms of Parkinson’s. Throughout this article, the term “pain” refers to the physical pain. 

What are the causes of pain in Parkinson’s?

a) Non-Parkinson’s disorders

Just as any other non-Parkinson’s patients, Parkinson’s patients (especially the older patients), have many coexisting medical disorders which result in pain, e.g. “bony spurs” at the neck which compress the nerves (leading to shoulder or arm pain) and diabetes (which often causes painful nerve disorders, especially at the hands and feet). Some Parkinson’s patients, especially at the advanced stage of illness, develop tendency to fall (loss of balance) which leads to fracture of hip and spine. Knee joint disorder (osteoarthritis) is another common cause of pain.

b) Parkinson’s-related disorders

However, in addition to pain caused by the non-Parkinson’s medical conditions mentioned above, many people are not aware that 39.3% of Parkinson’s patients have chronic pain which is directly related to Parkinson’s itself (Negre-Pages L et al, 2008). These researchers discovered that pain was twice more frequent in Parkinson’s patients than in patients without Parkinson’s. This study concluded that chronic pain is frequent but underreported in Parkinson’s. It was recommended that doctors should be more aware of this problem and improve the pain-killer strategies.

How do we know that the pain is related to Parkinson’s?

There are several useful pointers (Quinn NP, 1998).

1. the pain is maximal at the side most affected by Parkinson’s (i.e. the side where the motor symptoms are more severe).
2. the pain is relieved by Parkinson’s medications.
3. in the presence of motor fluctuation, the pain is usually present during the “wearing off” phenomenon and “off” periods, and is relieved during the “on” periods.

 

What are the Parkinson’s-related disorders which give rise to pain?

i) Muscle contraction (rigidity)

Muscle contraction is the most common cause of Parkinson’s-related pain. The pain is caused by persistent muscle contraction, and commonly felt at one side of the body such as the shoulder, arm and leg. Sometimes, the pain may be felt at the neck. It is usually described as constant, aching pain which affects the whole part of the limb. This pain affects the side of the body where the motor symptoms are more severe or have originated from (as illustrated by Patient 1). The pain is worse during the “wearing off” periods, as the muscle spasm or contraction is intensified at this stage.   

The pain has a tendency to precede the onset of motor symptoms by 1-2 years. Shoulder pain and frozen shoulder are known to be the early symptoms of Parkinson’s (Cleeves L, 1989; Riley D et al, 1989). As such, some Parkinson’s patients who initially experienced shoulder pain (as illustrated by Patient 2) or frozen shoulder are referred to the orthopedic (bone) specialist before they are subsequently discovered to have Parkinson’s.

Treatment: Parkinson’s medications usually help in relieving the pain. Physiotherapy can also be beneficial.

Case illustrations (true stories)

Patient 1

A 62 year-old man has been diagnosed to have Parkinson’s for two years. His initial complaints were stiffness, tremor and difficulty in movement on the left side of his body. He responded well to Ropinirole 2 mg three times a day.

Recently, he started to have mild and constant aching pain on the left upper and lower limbs, which was present the moment he woke up in the morning. The aching pain was felt all over the left upper and lower limbs, and affected his concentration while doing his work. He did not feel any tingling sensation or numbness. Being a right-handed person, his hand function was relatively preserved.  

Physical examination revealed mask-like facial expression and moderately severe stiffness of the left upper and lower limbs. He also had rest tremor on the left side. The movement of the left upper limbs was quite slow. The right limbs were fairly normal. No dystonia or dyskinesia was noted. When he walked, the left arm did not swing.

The muscle stiffness and tremor did not give him much trouble as he could even travel overseas regularly to carry out his work. His physical mobility was not affected. Obviously, the left-sided pain was more disabling than his motor symptoms.

A golden rule in the management of Parkinson’s is that one should not attribute every single new symptom to Parkinson’s – there could be other possibility such as nerve disorder. An important consideration was compression of the nerve in the neck due to bony spurs. An MRI scan of his neck spine did not show any evidence of nerve compression. Computerized nerve study also did not show any evidence of nerve disorder which could account for the aching sensation of the left-sided limbs.

Following the increase in the dose of Ropinirole to 4 mg three times a day, his pain was relieved. He also reported that the standard painkillers helped to reduce the pain, to a certain extent.

However, he had another problem that had worsened his left-sided pain. He had been a socially active businessman who traveled overseas regularly. The very diagnosis of Parkinson’s and also the difficulty in going to airport had made him quite depressed. I believe that his underlying depression has contributed to his left-sided pain.

I explained to him that he had underlying depression and could benefit from antidepressant medications. However, he was not keen to take antidepressant because he thought he could cope with his emotional disorder. True enough, he eventually managed to live with his pain and continued his daily work, till today.    

Comments

This gentleman was quite disabled by the aching pain of the left upper and lower limbs which was caused by the muscle stiffness of Parkinson’s. Treatment with Parkinson’s medications often relieves the pain. In any Parkinson’s patient with pain, any underlying depression should be considered. Treatment with antidepressant can also improve the pain. The relationship between pain and depression in Parkinson’s is further discussed below.    

Patient 2

Mr. Quah (not the real name), a 56 year-old Chinese man, worked as an acupuncturist at a traditional Chinese medical clinic in Kuala Lumpur.

In October 2004, he had a new problem. He had left shoulder and arm pain which he described as constant aching pain. His left shoulder also became stiff.

He consulted a general practitioner, who said, “What you are experiencing is due to some “bony spurs in your neck” which are compressing your nerves, causing the left arm pain.” Mr. Quah was given some painkillers and nerve medications, which did not relieve the aching left arm and stiff neck.
Subsequently, he was referred to the orthopedic (bone) surgeon who also told him that he had “bony spurs in the neck”. He was recommended to undergo physiotherapy at a local teaching hospital, where he underwent regular neck traction (for the bony spurs in his neck). Again, his symptoms did not improve.

By April 2005, he noticed that his left hand had started trembling. The tremor was worse when he was anxious or doing his acupuncture work. Being a left-handed person, Mr. Quah had difficulty inserting the acupuncture needles, to the extent that his clients had complained that it felt more painful than before. His body movement became slow. It was only at this juncture that the neurologist diagnosed him to have Parkinson’s.

Today, he is on Pramipexole 0.5 mg tds, Amantadine 100 mg tds and Benzhexol 2 mg tds. The shoulder pain has almost completely disappeared. His clients do not complain anymore that his acupuncture treatment is painful.

Comments

This gentleman had early manifestations of Parkinson’s such as left shoulder and arm pain that was initially and wrongly attributed to “bony spurs in the neck”. As many doctors and Parkinson’s patients are not aware of the non-motor symptoms of Parkinson’s, the one-sided pain in Parkinson’s is commonly attributed to disorders of neck bone (cervical disc prolapse). Obviously, this patient had walked into the “wrong clinic”. 

ii) Dyskinesia

Dyskinesia is uncontrollable, jerky and irregular body movement that occurs partly as a side effect of levodopa. When severe, dyskinesia results in prolonged episodes of muscular contraction which have the same effect of “running non-stop for a few kilometers”. Many patients feel exhausted after an episode of dyskinesia, which follows each dose of levodopa. Thus, pain due to dyskinesia occurs as part of the “on” periods. Dyskinetic pain is often described as aching pain. As dyskinesia is a common complication of levodopa treatment, and almost all Parkinson’s patients eventually need levodopa, dyskinesia is an important cause of pain in Parkinson’s.

Furthermore, the twisting movement of dyskinesia may aggravate the non-Parkinson’s causes of pain such as neck bone disorder (cervical disc prolapse).    

Treatment: measures to reduce dyskinesia helps in relieving of dyskinetic pain. These include reducing the individual doses of levodopa, adding dopamine agonists and / or amantadine, and the use of Apomorphine skin injection.   

iii) Dystonia

Dystonia refers to sustained, forceful and twisting body moments that lead to abnormal body position or deformities. Dystonia can affect almost every part of the body, particularly the neck and foot. Commonly, dystonia results in painful muscle cramps affecting the calf muscles, which is associated with upgoing toes. Dystonic pain is most commonly felt upon awakening in the morning, when the effect of the previous evening dose of Parkinson’s medications has worn off. In other words, pain due to dystonia occurs as part of the “off” periods.

Treatment: Dystonia does not always result in significant pain. In these cases, it is not necessary to start any specific treatment. In fact, many patients learn to get use to the dystonia. However, when the dystonic pain is unbearable or disabling, measures which relieve the early morning dystonia can reduce the dystonic pain, such as evening dose of long-acting levodopa (Madopar HBS or Sinemet CR) and dopamine agonist. In severe cases, injection of Botox (a medication which reduces muscle contraction) is needed.

iv) Restless leg syndrome (RLS)

RLS is a neurological disorder which is associated with Parkinson’s. RLS is characterized by unpleasant sensations in the legs which are typically present when the legs are at rest, e.g. sitting or lying on bed. The unpleasant sensations lead to an uncontrollable urge to move the legs (e.g. walking about the room) which relieves these unpleasant feelings. RLS sensations are often described as burning, creeping, tugging, or like insects crawling inside the legs. Sometimes, the unpleasant abnormal sensations can be irritating or even painful.

Treatment: as RLS is also related to abnormal dopamine activity in the brain, dopamine agonists are helpful in relieving the symptoms of RLS.  

v) Central pain

This is a rare pain disorder in Parkinson’s. It is thought to be a direct consequence of Parkinson’s itself (i.e. the changes in the brain of Parkinson’s patients), and not due to the disorders mentioned from i) to iv) above. The basal ganglia (the part of the brain which is principally affected in Parkinson’s) may have a role in modifying sensory information in the body (Chudler EH, 1995). Thus, a disturbance in the function of basal ganglia in Parkinson’s may result in a lower pain threshold in Parkinson’s patients compared with healthy people (Djaldetti R et al, 2004). In addition, dopamine has been known to play a role in the regulation of pain in the brain. 

Manifestations of central pain include painful, burning, stabbing, aching, itching, or tingling sensations, which may even precede the motor symptoms of Parkinson’s. Central pain can affect any part of the body.

It has to be emphasized other medical disorders which commonly cause such pain symptoms (e.g. diabetes, vitamin B deficiency) be excluded before one makes a diagnosis of central pain. A computerized nerve conduction study should also be considered to exclude nerve disorders of the limbs.

Treatment: it is difficult to treat the central pain in Parkinson’s. Currently, there is no known effective and specific treatment for this disorder. Unfortunately, central pain responds poorly to Parkinson’s medications.

Some people have suggested using gabapentin (Neurontin), but this has not been unequivocally confirmed to be effective. Consulting a pain specialist may help.

The rarer types of pain in Parkinson’s

Some Parkinson’s patients complain of oral and genital pain which tends to fluctuate in severity with the motor symptoms of Parkinson’s, and responds to Parkinson’s medications (Ford B et al, 1996). Burning mouth is another complaint among Parkinson’s patients which is poorly understood (Clifford TJ et al, 1998).

The relationship between pain and depression in Parkinson’s

Depression and pain are common in Parkinson’s. A significant relationship between pain and depression was found among Parkinson’s patients (Ehrt U, 2009). Depression seems to increase the severity of pain in Parkinson’s patients (depressed Parkinson’s patients seem to be more sensitive to pain). On the other hand, the presence of pain may lead to depression. Thus, there seems to be a “chicken-and-egg” relationship between pain and depression in Parkinson’s.

Treatment: any coexisting depression should be considered in any Parkinson’s patient with pain, and vice versa, as illustrated in the following story:

Case illustration (true story)

A 67-year-old lady was recently diagnosed to have very mild Parkinson’s. She also complained of bilateral feet pain which is described as aching, and triggered by prolonged standing or walking. This aching pain has troubled her to the extent that she can’t stand for longer than 20 minutes, and unable to carry out her daily activities such as cooking and cleaning up the home. Almost everyday, she asked her children to bring her to the doctor’s clinic to treat her feet pain.

When I examined her, all I could notice was flat feet (the loss of the normal curvature of the base of the foot). There was hardly any physical evidence of Parkinson’s. She was referred to the orthopedic (bone) surgeon who agreed that she had flat feet, which caused her feet pain. However, the surgeon did not advise her to undergo feet surgery as he thought her feet problem was not severe.

Despite the reassurance of the surgeon, she was still so preoccupied with the feet pain. Each time she came back to my clinic, her complaint was always the same – “I can’t walk around at home or cook because my feet are hurting me”.

Having noticed that she also had a few symptoms of depression such as insomnia, lethargy and loss of appetite, I asked her whether there was any personal problem which was bothering her. She said, “No. There is nothing which is making me upset except my feet pain.”

After asking her the same question several times over a few months period, finally she managed too open up to me. “I feel sad because of my son. He can’t get along with all my other children.”

Further questioning revealed that she had family problem which had made her depressed.  She had a rebellious son who refused to speak to each of his siblings.

I told her that 80% of her disability was caused by depression, while her flat feet and Parkinson’s merely contributed to 10% each to her disability. Her “painful feet” was merely a way for her to distract herself from her son’s rebellious behaviour, and thus relieving her mental stress.

So, instead of focusing on her feet pain, I suggested to her that we should focus on her main problem, which was depression. I started her on antidepressant. A few weeks later, when I saw her again, she did not complain about the feet pain anymore.   

Why is pain under-recognized in Parkinson’s?

Just as the non-motor symptoms, the pain in Parkinson’s is obviously under-recognized and under-treated. Many doctors and patients are still preoccupied with the movement disorder in Parkinson’s, and thus not paying enough attention to the pain in Parkinson’s.

The non-specific nature of pain in Parkinson’s also makes it difficult to be recognized. For example, symptoms such as burning sensation, numbness and tingling are also found in other nerve disorders, especially diabetes.

The DBS surgery and pain

Since the DBS surgery results in improvement of body stiffness, dyskinesia and dystonia, it is not surprising that a study has reported that DBS surgery improved pain in Parkinson’s patients (Kim HJ et al, 2008). Interestingly, the DBS surgery has been reported to be beneficial in the management of chronic pain due to nerve disorders in non-Parkinson’s patients.

Conclusions

Parkinson’s is a physically painful brain disorder. The pain in Parkinson’s is under-recognized and under-treated. Various treatment options for pain are available such as Parkinson’s medications and DBS surgery, which can potentially improve the quality of life. The relationship between pain and depression in Parkinson’s should be recognized. The optimal treatment of Parkinson’s includes the relief of both motor and non-motor symptoms.  

In other words, Parkinson’s does not have to be that painful.  

References

Chudler EH, Dong WK. The role of the basal ganglia in nociception and pain. Pain 1995; 60(1): 3-38.
Cleeves L, Findley LJ.Frozen shoulder and other shoulder disturbances in Parkinson's disease. J Neurol Neurosurg Psychiatry 1989; 52: 813-814.
Clifford TJ, Warsi MJ, Burnett CA, et al. Burning mouth in Parkinson's disease sufferers. Gerodontology 1998: 15(2): 73-8.
Djaldetti R, Shifrin A, Rogowsky Z, et al. Quantitative measurement of pain sensation in patients with Par­kinson’s disease. Neurology 2004; 62: 2171-2175.

Ehrt U, Larsen JP, Aarsland D. Pain and its relationship to depression in Parkinson disease. Am J Geriatr Psychiatry. 2009; 17(4): 269-75.

Ford B, Louis ED, Greene P, et al. Oral and genital pain syndromes in Parkinson's disease. Mov Disord 1996; 11(4): 421-6.
Kim HJ, Paek SH, Kim JY, et al. Chronic subthalamic deep brain stimulation improves pain in Parkinson disease. J Neurol. 2008; 255(12): 1889-94.
Negre-Pages L, Regragui W, Bouhassira D, et al. Chronic pain in Parkinson's disease: The cross-sectional French DoPaMiP survey. Mov Disord 2008; 23 (10): 1361-1369.
Quinn NP. Classification of fluctuations in patients with Parkinson’s disease. Neurology 1998; 51 (Suppl 2): S25-S29.
Riley D, Lang AE, Blair RDG, et al. Frozen shoulder and other shoulder disturbances in
Parkinson's disease. J Neurol Neurosurg Psychiatry 1989; 52: 63-66.

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).  

Pathologic gambling

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.     

Hypersexuality  

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”).

Compulsive shopping     

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.

Compulsive eating    

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.

 

  

References

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.
Uitti RJ Tanner CM, Rajput AH, et al. Hypersexuality with antiparkinsonian therapy. Clin Neuropharmacol 1989;12(5): 375-83.
Voon V, Hassan K, Zurowski M, et al. Prevalence of repetitive and reward-seeking behaviours in Parkinson’s disease. Neurology 2006; 67: 1254-1257.