Management of impulse control disorders in Parkinson's disease: Controversies and future approaches

Neuropsychiatric Issues in Parkinson's Disease

Cognitive and neuropsychiatric symptoms are common in Parkinson's Disease and may surpass motor symptoms as the major factors impacting patient quality of life. The symptoms may be broadly separated into those associated with the disease process and those that represent adverse effects of treatment. Symptoms attributed to the disease arise from pathologic changes within multiple brain regions and are not restricted to dysfunction in the dopaminergic system. Mood symptoms such as depression, anxiety, and apathy are common and may precede the development of motor symptoms by years, while other neuropsychiatric symptoms such as cognitive impairment, dementia, and psychosis are more common in later stages of the disease. Neuropsychiatric symptoms attributed to treatment include impulse control disorders, pathologic use of dopaminergic medications, and psychosis. This manuscript will review the current understanding of neuropsychiatric symptoms in Parkinson's Disease.

Introduction to Parkinson disease (PD) and its complications

Parkinson disease (PD) is a common neurodegenerative disorder in older adults characterized by motor and nonmotor symptoms and complications. Impulse control disorders (ICDs), such as pathological gambling, compulsive shopping, compulsive sexual behavior (hypersexuality), and binge eating disorder, affect 13.6% of the PD population. Use of dopamine receptor agonists (DRAs) is considered a major risk factor for ICD development. Amantadine and a high dose of levodopa were linked to ICDs to a lesser extent than DRAs. Based on the severity of behavior(s), ICDs can negatively impact social, professional, and familial lives of patients and their families. Ideally, all PD patients taking DRAs, high doses of levodopa, and/or amantadine should be routinely asked about or monitored for ICDs during therapy initiation and continuation. Dose decrease or withdrawal of the offending agent, primarily DRAs, is usually the most effective first step in ICD management. Careful dose adjustment with close monitoring is warranted due to risk for worsening of motor symptoms or emergence of dopamine agonist withdrawal syndrome (DAWS). About 1/3 of PD patients with ICD who decrease or discontinue DRA experienced DAWS. The lowest dose of DRA will need to be continued to balance ICDs and DAWS as it is not alleviated by other dopaminergic or psychotropic medications. Other therapies with low empiric evidence, such as amantadine, naloxone, cognitive behavior therapy, deep brain stimulation, and psychopharmacotherapy showed mixed results for ICD management. It is crucial that clinicians are familiar with the psychiatric complications of PD, including ICDs, beyond mere recognition and management of motor symptoms.

A Retrospective Evaluation of the Frequency of Impulsive Compulsive Behaviors in Parkinson's Disease Patients Treated with Continuous Waking Day Apomorphine Pumps

Background

Impulsive compulsive behaviors (ICBs) can have a deleterious impact on the lives of patients with PD with orally active dopamine agonist treatment recognized as the greatest risk factor. However, the relationship between subcutaneous administration of the dopamine agonist, apomorphine, and impulsive compulsive behaviors is unknown.

Methods

We conducted a retrospective analysis of 28 advanced PD patients treated with subcutaneous waking day apomorphine ambulatory minipumps at the National Hospital for Neurology and Neurosurgery (London, UK).

Results

Twelve of the patients had experienced impulsive compulsive behaviors before starting apomorphine. Reduction of oral dopamine agonist dose before apomorphine had led to complete resolution in 6 cases with no recurrence on long-term apomorphine maintenance therapy. Six patients still had active impulsive compulsive behaviors when apomorphine was started. Four of these improved, and in the other 2 there was no worsening. Of the 16 patients with no previous history of impulsive compulsive behaviors who started apomorphine, only 1, who was still receiving concurrent levodopa, developed impulsive compulsive behaviors.

Conclusions

These data provide preliminary evidence that continuous apomorphine pump therapy has a lower proclivity to trigger or exacerbate impulsive compulsive behaviors than oral dopamine agonists. This is likely to be attributed to a more tonic stimulation of striatal dopamine receptors leading to desensitisation, but could also be attributed to a different pharmacological profile of apomorphine compared with orally active dopamine agonists. Apomorphine can be considered as a treatment option in patients who have developed disabling impulsive compulsive behaviors on oral agonist therapy whose motor handicap cannot be controlled adequately on l-dopa alone. Further prospective studies are needed to provide a definitive answer to this question.

Apathy and Impulse Control Disorders: Yin & Yang of Dopamine Dependent Behaviors

Neuropsychiatric symptoms are common non-motor symptoms in Parkinson's disease (PD). Apathy and impulse control disorders (ICD) are two opposite motivational expressions of a continuous behavioural spectrum involving hypo- and hyperdopaminergia. Both syndromes share pathological (decreased vs increased) dopamine receptor stimulation states. Apathy belongs to the spectrum of hypodopaminergic symptoms together with anhedonia, anxiety and depression. Apathy is a key symptom of PD which worsens with disease progression. Animal models, imaging and pharmacological studies concur in pointing out dopaminergic denervation in the aetiology of parkinsonian apathy with a cardinal role of decreased tonic D2/D3 receptor stimulation. ICDs are part of the hyperdopaminergic behavioural spectrum, which also includes punding, and dopamine dysregulation syndrome (DDS), which are all related to non-physiological dopaminergic stimulation induced by antiparkinsonian drugs. According to clinical data tonic D2/D3 receptor stimulation can be sufficient to induce ICDs. Clinical observations in drug addiction and PD as well as data from studies in dopamine depleted rodents provide hints allowing to argue that both pulsatile D1 and D2 receptor stimulation and the severity of dopaminergic denervation are risk factors to develop punding behavior and DDS. Imaging studies have shown that the brain structures involved in drug addiction are also involved in hyperdopaminergic behaviours with increase of bottom-up appetitive drive and decrease in prefrontal top down behavioural control.

Impulse control disorder related behaviours during long-term rotigotine treatment: a post hoc analysis

Background and purpose

Dopamine agonists in Parkinson's disease (PD) are associated with impulse control disorders (ICDs) and other compulsive behaviours (together called ICD behaviours). The frequency of ICD behaviours reported as adverse events (AEs) in long‐term studies of rotigotine transdermal patch in PD was evaluated.

Methods

This was a post hoc analysis of six open‐label extension studies up to 6 years in duration. Analyses included patients treated with rotigotine for at least 6 months and administered the modified Minnesota Impulse Disorders Interview. ICD behaviours reported as AEs were identified and categorized.

Results

For 786 patients, the mean (±SD) exposure to rotigotine was 49.4 ± 17.6 months. 71 (9.0%) patients reported 106 ICD AEs cumulatively. Occurrence was similar across categories: 2.5% patients reported ‘compulsive sexual behaviour’, 2.3% ‘buying disorder’, 2.0% ‘compulsive gambling’, 1.7% ‘compulsive eating’ and 1.7% ‘punding behaviour’. Examining at 6‐month intervals, the incidence was relatively low during the first 30 months; it was higher over the next 30 months, peaking in the 54–60‐month period. No ICD AEs were serious, and 97% were mild or moderate in intensity. Study discontinuation occurred in seven (9.9%) patients with ICD AEs; these then resolved in five patients. Dose reduction occurred for 23 AEs, with the majority (73.9%) resolving.

Conclusions

In this analysis of >750 patients with PD treated with rotigotine, the frequency of ICD behaviour AEs was 9.0%, with a specific incidence timeline observed. Active surveillance as duration of treatment increases may help early identification and management; once ICD behaviours are present rotigotine dose reduction may be considered.

New clinical trials for nonmotor manifestations of Parkinson's disease

Nonmotor manifestations in Parkinson's disease (PD) encompass a range of clinical features, including neuropsychiatric problems, autonomic dysfunction, sleep disorders, fatigue, and pain. Despite their importance for patients' quality of life, the evidence base for their treatment is relatively sparse. Nevertheless, the last few years have seen a number of new trials starting that specifically address nonmotor features as an outcome measure in clinical trials. Large randomized, controlled trials in the last 3 years reported improvement of psychosis with the new selective serotonin 5-HT2A inverse agonist pimavanserin and of postural hypotension with the oral norepinephrine precursor droxidopa. Smaller new randomized, controlled trials support the effectiveness of Deep Brain Stimulation and opiates for pain, of rivastigmine for apathy and piribedil for apathy post-DBS, group cognitive behavioral therapy for depression and/or anxiety, continuous positive airway pressure for sleep apnea in PD and doxepin for insomnia, and of solifenacin succinate and transcutaneous tibial nerve stimulation for urinary symptoms. A number of new smaller or open trials as well as post-hoc analyses of randomized, controlled trials have suggested usefulness of other treatments, and new randomized, controlled trials are currently ongoing.

Psychosis and concurrent impulse control disorder in Parkinson's disease: A review based on a case report

Psychosis, impulse control disorders (e.g., pathological gambling and hypersexuality) and repetitive behaviors such as punding are known psychiatric complications of Parkinson's disease (PD). Impulsive, compulsive and repetitive behaviors are strongly associated with dopamine-replacement therapy. We present the case of a 58-year-old man with PD and a myriad of psychiatric symptoms. Concurrent psychosis, punding and pathological gambling developed more than six years after the introduction of pramipexole and ceased shortly after the addition of quetiapine and discontinuation of pramipexole. This report emphasizes the importance of monitoring for a wide array of psychiatric symptoms in patients on dopamine replacement therapy.

A review of adverse events linked to dopamine agonists in the treatment of Parkinson's disease

INTRODUCTION

Dopamine agonists are highly effective as adjunctive therapy to levodopa in advanced Parkinson's disease. These drugs have rapidly gained popularity as a monotherapy in the early stages of Parkinson's disease for patients less than 65-70 years old since they are about as effective as levodopa but patients demonstrate a lower tendency to develop motor complications. However, dopamine agonists could have peripheral and central side-effects which are often the reason for the discontinuation of the treatment.

AREAS COVERED

This article presents an overview of the efficacy and the potential negative effects related to the use of dopamine agonists in the treatment of Parkinson's disease.

EXPERT OPINION

Beyond the new generation non ergot dopamine agonists, no strong evidences allow the choice of a specific dopamine agonists for Parkinson 's disease treatment and by now dopamine agonists treatment should be tailored on specific adverse events profile.

Transplantation of human retinal pigment epithelial cells in the nucleus accumbens of cocaine self-administering rats provides protection from seeking

Chronic exposure to drugs and alcohol leads to damage to dopaminergic neurons and their projections in the 'reward pathway' that originate in the ventral tegmental area (VTA) and terminate in the nucleus accumbens (NAc). This damage is thought to contribute to the signature symptom of addiction: chronic relapse. In this study we show that bilateral transplants of human retinal pigment epithelial cells (RPECs), a cell mediated dopaminergic and trophic neuromodulator, into the medial shell of the NAc, rescue rats with a history of high rates of cocaine self-administration from drug-seeking when returned, after 2 weeks of abstinence, to the drug-associated chamber under extinction conditions (i.e., with no drug available). Excellent survival was noted for the transplant of RPECs in the shell and/or the core of the NAc bilaterally in all rats that showed behavioral recovery from cocaine seeking. Design based unbiased stereology of tyrosine hydroxylase (TH) positive cell bodies in the VTA showed better preservation (p<0.035) in transplanted animals compared to control animals. This experiment shows that the RPEC graft provides beneficial effects to prevent drug seeking in drug addiction via its effects directly on the NAc and its neural network with the VTA.

What Engineering Technology Could Do for Quality of Life in Parkinson's Disease: A Review of Current Needs and Opportunities

Parkinson's disease (PD) involves well-known motor symptoms such as tremor, rigidity, bradykinesia, and altered gait, but there are also nonlocomotory motor symptoms (e.g., changes in handwriting and speech) and even nonmotor symptoms (e.g., disrupted sleep, depression) that can be measured, monitored, and possibly better managed through activity-based monitoring technologies. This will enhance quality of life (QoL) in PD through improved self-monitoring and also provide information that could be shared with a healthcare provider to help better manage treatment. Until recently, nonmotor symptoms ("soft signs") had been generally overlooked in clinical management, yet these are of primary importance to patients and their QoL. Day-to-day variability of the condition, the high variability in symptoms between patients, and the isolated snapshots of a patient in periodic clinic visits make better monitoring essential to the proper management of PD. Continuously monitored patterns of activity, social interactions, and daily activities could provide a rich source of information on status changes, guiding self-correction and clinical management. The same tools can be useful in earlier detection of PD and will improve clinical studies. Remote medical communications in the form of telemedicine, sophisticated tracking of medication use, and assistive technologies that directly compensate for disease-related challenges are examples of other near-term technology solutions to PD problems. Ultimately, a sensor technology is not good if it is not used. The Parkinson's community is a sophisticated early adopter of useful technologies and a group for which engineers can provide near-term gratifying benefits.

Cannabinoids and Tremor Induced by Motor-related Disorders: Friend or Foe?

Tremor arises from an involuntary, rhythmic muscle contraction/relaxation cycle and is a common disabling symptom of many motor-related diseases such as Parkinson disease, multiple sclerosis, Huntington disease, and forms of ataxia. In the wake of anecdotal, largely uncontrolled, observations claiming the amelioration of some symptoms among cannabis smokers, and the high density of cannabinoid receptors in the areas responsible for motor function, including basal ganglia and cerebellum, many researchers have pursued the question of whether cannabinoid-based compounds could be used therapeutically to alleviate tremor associated with central nervous system diseases. In this review, we focus on possible effects of cannabinoid-based medicines, in particular on Parkinsonian and multiple sclerosis-related tremors and the common probable molecular mechanisms. While, at present, inconclusive results have been obtained, future investigations should extend preclinical studies with different cannabinoids to controlled clinical trials to determine potential benefits in tremor.

Dyskinesias and impulse control disorders in Parkinson's disease: From pathogenesis to potential therapeutic approaches

Dopaminergic treatment in Parkinson's disease (PD) reduces the severity of motor symptoms of the disease. However, its chronic use is associated with disabling motor and behavioral side effects, among which levodopa-induced dyskinesias (LID) and impulse control disorders (ICD) are the most common. The underlying mechanisms and pathological substrate of these dopaminergic complications are not fully understood. Recently, the refinement of imaging techniques and the study of the genetics and molecular bases of LID and ICD indicate that, although different, they could share some features. In addition, animal models of parkinsonism with LID have provided important knowledge about mechanisms underlying such complications. In contrast, animal models of parkinsonism and abnormal impulsivity, although useful regarding some aspects of human ICD, do not fully resemble the clinical phenotype of ICD in patients with PD, and until now have provided limited information. Studies on animal models of addiction could complement the previous models and provide some insights into the background of these behavioral complications given that ICD are regarded as behavioral addictions. Here we review the most relevant advances in relation to imaging, genetics, biochemistry and pharmacological interventions to treat LID and ICD in patients with PD and in animal models with a view to better understand the overlapping and unique maladaptations to dopaminergic therapy that are associated with LID and ICD.

Update on deep brain stimulation in Parkinson's disease

Deep brain stimulation (DBS) is considered a safe and well tolerated surgical procedure to alleviate Parkinson’s disease (PD) and other movement disorders symptoms along with some psychiatric conditions. Over the last few decades DBS has been shown to provide remarkable therapeutic effect on carefully selected patients. Although its precise mechanism of action is still unknown, DBS improves motor functions and therefore quality of life. To date, two main targets have emerged in PD patients: the globus pallidus pars interna and the subthalamic nucleus. Two other targets, the ventralis intermedius and zona incerta have also been selectively used, especially in tremor-dominant PD patients. The main indications for PD DBS have traditionally been motor fluctuations, debilitating medication induced dyskinesias, unpredictable “off time” state, and medication refractory tremor. Medication refractory tremor and intolerable dyskinesia are potential palliative indications. Besides aforementioned targets, the brainstem pedunculopontine nucleus (PPN) is under investigation for the treatment of ON-state freezing of gait and postural instability. In this article, we will review the most recent literature on DBS therapy for PD, including cutting-edge advances and data supporting the role of DBS in advanced neural-network modulation.