Impulse control disorders in Parkinson's disease: A 20‐year odyssey

Unveiling the Burden of Drug-Induced Impulsivity: A Network Analysis of the FDA Adverse Event Reporting System

INTRODUCTION

Impulsivity induced by dopaminergic agents, like pramipexole and aripiprazole, can lead to behavioral addictions that impact on social functioning and quality of life of patients and families (e.g., resulting in unemployment, marital problems, anxiety). These secondary effects, interconnected in networks of signs and symptoms, are usually overlooked by clinical trials, not reported in package inserts, and neglected in clinical practice.

OBJECTIVE

This study explores the syndromic burden of impulsivity induced by pramipexole and aripiprazole, pinpointing key symptoms for targeted mitigation.

METHODS

An event-event Information Component (IC) on the FDA Adverse Event Reporting System (FAERS) (January 2004 to March 2022) identified the syndrome of events disproportionally co-reported with impulsivity, separately for pramipexole and aripiprazole. A greedy-modularity clustering on composite network analyses (positive pointwise mutual information [PPMI], Ising, Φ) identified sub-syndromes. Bayesian network modeling highlighted possible precipitating events.

RESULTS

Suspected drug-induced impulsivity was documented in 7.49% pramipexole and 4.50% aripiprazole recipients. The highest IC concerned obsessive-compulsive disorder (reporting rate = 26.77%; IC median = 3.47, 95% confidence interval [CI] = 3.33-3.57) and emotional distress (21.35%; 3.42, 3.26-3.54) for pramipexole, bankruptcy (10.58%; 4.43, 4.26-4.55) and divorce (7.59%; 4.38, 4.19-4.53) for aripiprazole. The network analysis identified delusional jealousy and dopamine dysregulation sub-syndromes for pramipexole, obesity-hypoventilation and social issues for aripiprazole. The Bayesian network highlighted anxiety and economic problems as potentially precipitating events.

CONCLUSION

The under-explored consequences of drug-induced impulsivity significantly burden patients and families. Network analyses, exploring syndromic reactions and potential precipitating events, complement traditional techniques and clinical judgment. Characterizing the secondary impact of reactions will support informed patient-centered decision making.

APOE contributes to longitudinal impulse control disorders progression in Parkinson's disease

BACKGROUND

Impulse control disorders (ICDs) are an increasingly recognized complication in Parkinson disease (PD). The pathogenesis of ICDs is currently unclear. Few genetic studies have been conducted in this area.

OBJECTIVE

We aimed to ascertain the correlation between APOE and ICDs, and identify clinical predictors of ICDs in PD.

METHODS

This study included 287 PD patients from the Parkinson's Progression Markers Initiative. They were followed up to investigate the progression of ICDs over a period of 5 years. The cumulative incidence of ICDs and potential risk factors were evaluated using Kaplan-Meier and Cox regression analyses.

RESULTS

44.3% (31/70) patients with APOE ɛ4 and 32.3% (70/217) patients without APOE ɛ4 developed ICDs during the five-year follow up period. There were significant differences between the PD with and without ICDs development group in age, MSEADLG score, ESS score, GDS score, and STAI score at baseline. In multivariable Cox regression analysis, APOE ε4 (HR = 1.450, p = 0.048) and STAI score (HR = 1.017, p = 0.001) were predictors of the development of ICDs. Patients with APOE ɛ4 group showed significantly lower CSF Aβ42 and CSF α-syn level than patients without APOE ɛ4 group at baseline. In patients with APOE ɛ4 group, the "low α-syn level" group and the "low ptau/tau ratio" group had a significantly higher incidence of ICDs, respectively.

CONCLUSIONS

This study provides important insights into the potential role of the APOE gene in the development of ICDs in PD. Further studies are needed to confirm our findings and to investigate the underlying mechanisms in more detail.

Impulse Control Disorders in Patients with Pituitary Tumors Treated with Dopamine Agonists: A Systematic Review

BACKGROUND

The increased prevalence of Impulse Control Disorders (ICDs) in dopamine agonist (DA) treated patients with Parkinson's disease is well described. Despite the frequent use of DAs in the management of pituitary tumors, the relationship between DAs and prevalence of ICDs in patients with pituitary tumours is unclear.

AIMS

To establish the prevalence of ICDs in patients with prolactinoma or acromegaly and determine whether prevalence differs in those on DAs to those treated without.

METHODS

Systematic review of the literature (registered a priori) reporting prevalence of ICDs in patients with prolactinoma or acromegaly (conducted June 2023). A narrative synthesis describing prevalence of ICDs according to assessment method was performed. Prevalence comparisons between patients with prolactinoma or acromegaly treated with DAs, to patients treated without, were summarised.

RESULTS

Studies were largely retrospective, observational and heterogenous, with few patients with prolactinoma and acromegaly treated without DA. Prevalence of ICDs varied between 0-60% in patients with prolactinoma, and from 5-23% in studies with at least five patients with acromegaly. In most studies comparing DA exposed to non-DA exposed cases, DA use was not associated with ICDs.

CONCLUSIONS

Reported prevalence of ICDs in patients with prolactinoma and acromegaly varies considerably. Given ICDs were reported to be highly prevalent in some studies, clinicians should be mindful of these potentially serious disorders. ICD screening tools validated for use in patients with pituitary tumors combined with prospective studies including appropriate controls, are necessary to accurately establish prevalence of ICDs and true impact of DAs in their development.

Improving Documentation of Impulse Control Disorders at a Movement Disorder Program During the COVID-19 Pandemic

Background and Objectives

Impulse control disorders (ICD) are a group of behaviors in Parkinson disease (PD), (compulsive buying, gambling, binge eating, craving sweets, and hypersexuality) that occur in up to 20% of individuals with PD, sometimes with devastating results. We sought to determine the rate of ICD screening based on 2020 quality measures for PD care by the American Academy of Neurology.

Methods

We conducted a quality improvement project to document and improve physician ICD screening in a tertiary movement disorder program. Serial medical records were reviewed for 5 weeks before and 13 weeks after an educational session and documentation tool deployments in 2020. Inclusion criteria included the following: idiopathic PD, PD dementia (PDD), or dementia with Lewy bodies (DLB). Individual encounters for 109 patients preintervention and 276 patients postintervention were reviewed.

Results

There was no difference between the preintervention and postintervention (pre-IG vs post-IG, respectively) in terms of age, male to female ratio, proportion of patients with PD, PDD, or DLB, duration of diagnosis, or levodopa equivalents. There was a shift to increased ICD queries above the median for the study period (28.8%) for 7 consecutive weeks in post-IG. The frequency of ICD diagnosis was not different from pre-IG to post-IG (95% confidence interval, 0-32.6 vs 2.7-13.4%, p = 0.444).

Discussion

ICD queries immediately after ICD education and dissemination of documentation tools increased. Both preintervention and postintervention groups were similar in demographic and clinical characteristics. This program was instituted at the height of wave 2 of the COVID-19 pandemic in Alberta during staff redeployment and 100% shift to telemedicine ambulatory care. Our results demonstrate that amid a crisis, quality improvement can still be effective with education and provision of tools for clinicians.

Association between metabolic syndrome components and impulse control disorders in Parkinson's disease

Background

Current evidence on management of impulse control disorders (ICDs) in Parkinson's disease (PD) remains scarce, and exploring modifiable risk factors is crucial.

Objective

We evaluated the profiles of ICDs in PD patients and aimed to determine the associations between ICDs, metabolic syndrome components and other clinical features.

Methods

We enrolled patients diagnosed with PD in this study and conducted comprehensive clinical assessments.

Results

We recruited 39 PD patients with ICDs and 66 PD patients without ICDs. Out of the 39 patients with ICDs, 19 (48.7%) had one impulse control disorder, while 20 (51.3%) had two or more. The most commonly reported symptom of ICDs was compulsive eating (48.7%). Significant differences were observed between the PD patients with and without ICDs in terms of their HbA1c levels, history of diabetes mellitus, dopamine agonist use, levodopa equivalent dose of dopamine agonists (LED DA), and Hamilton Depression Rating Scale (HAMD) scores. HbA1c levels were significantly higher in the PD patients with compulsive eating. Stepwise logistic regression analyses were performed with the dependent variables of ICDs (yes/no) and compulsive eating (yes/no). Among the 105 PD patients, those with ICDs exhibited higher levels of HbA1c, HAMD score and LED DA than those without ICDs (p < 0.01). Among 39 PD patients with ICDs, those with compulsive eating exhibited higher levels of HbA1c (OR = 2.148, 95% CI = 1.004-4.594, p < 0.05). Among 105 PD patients, those with compulsive eating exhibited higher levels of HbA1c, LED DA and HAMD score (p < 0.05).

Conclusion

This study provides insights into the profiles of ICDs in PD patients and their associations with various clinical features. Compulsive eating was the most common ICDs symptom reported. Notably, HbA1c levels were found to be higher in patients with compulsive eating, indicating that poor blood glucose control may be a potential risk factor for ICDs in PD. However, it should be noted that the higher HbA1c levels could also be a consequence of compulsive eating rather than a causal factor for ICDs in PD. Further research is needed to confirm the modifiable risk factors for ICDs in PD.

Exploring the underlying mechanisms of drug-induced impulse control disorders: a pharmacovigilance-pharmacodynamic study

INTRODUCTION

Impulse control disorders (e.g. pathological gambling, hypersexuality) may develop as adverse reactions to drugs. Pathogenetic hypotheses have mainly focused on D3-receptor agonism, and switching to alternatives with different pharmacologic mechanisms represents a common management strategy. Nonetheless, treatment failure is common and gaining pathophysiological insights is needed.

AIM

We aimed to identify targets potentially contributing to pathologic impulsivity.

METHOD

We performed a pharmacovigilance-pharmacodynamic study on dopamine agonists and antipsychotics using the Food and Drug Administration Adverse Event Reporting System (January 2004-December 2021). We estimated disproportionate reporting using the Bayesian information component. Using online public databases (IUPHAR, ChEMBL, PDSP, DrugBank), we calculated drug occupancies. To identify the targets potentially contributing to impulsivity, we fitted univariate regression models interpolating information components and occupancies within dopamine agonists and antipsychotics. Sensitivity analyses were performed to check for the robustness of the results.

RESULTS

Among 19 887 reports of impulsivity, 5898 recorded an antipsychotic, and 3100 a dopamine agonist. The more robust signals concerned aripiprazole (N = 3091; median information component [95% confidence interval] = 4.51[4.45-4.55]) and brexpiprazole (229; 4.00[3.78-4.16]) for antipsychotics, pergolide (105; 5.82[5.50-6.06]) and pramipexole (2009; 5.43[5.36-5.48]) for dopamine agonists. Robust, significant positive associations between drug occupancy and impulsivity reporting were found for D3 within dopamine agonists (beta = 1.52; P-value = 0.047) and 5-HT1a within antipsychotics (1.92, 0.029).

CONCLUSION

Our results supported the role of D3-receptor agonism in inducing impulsivity in dopamine receptor agonists and identified a potential role of 5-HT1a receptor agonism in antipsychotics. Investigating these receptors may drive towards a better management of drug-induced impulsivity.

Advances in the Therapeutic Use of Non-Ergot Dopamine Agonists in the Treatment of Motor and Non-Motor Symptoms of Parkinson's Disease

Dopamine (DA) agonists, as an excellent dopamine replacement therapy for patients with early and advanced Parkinson's disease (PD), play a vital role in controlling motor and several nonmotor symptoms. Besides, the application of DA agonists may delay levodopa therapy and the associated risk of motor complications. Indeed, each DA agonist has unique pharmacokinetic and pharmacodynamic characteristics and therefore has different therapeutic efficacy and safety profile. The comorbidities, significant non-motor manifestations, concomitant medications, and clinical features of PD individuals should guide the selection of a specific DA agonist to provide a more patient-tailored treatment option. Thorough knowledge of DA agonists helps clinicians better balance clinical efficacy and side effects. Therefore, this review refers to recent English-written articles on DA agonist therapy for PD patients and summarizes the latest findings on non-ergot DA agonists as well as the advantages and disadvantages of each compound to help clinicians in the selection of a specific DA agonist. In addition, novel D1/D5 partial agonists and new formulations of DA agonists are also discussed.

Drug-Induced Gambling Disorder: Epidemiology, Neurobiology, and Management

Problematic gambling has been suggested to be a possible consequence of dopaminergic medications used mainly in neurological conditions, i.e. pramipexole and ropinirole, and possibly by one antipsychotic compound, aripiprazole. Patients with Parkinson's disease, restless legs syndrome and other conditions potentially treated with dopamine agonists, as well as patients treated for psychotic disorders, are vulnerable patient groups with theoretically increased risk of developing gambling disorder (GD), for example due to higher rates of mental ill-health in these groups. The aim of the present paper is to review the epidemiological, clinical, and neurobiological evidence of the association between dopaminergic medications and GD, and to describe risk groups and treatment options. The neurobiology of GD involves the reward and reinforcement system, based mainly on mesocorticolimbic dopamine projections, with the nucleus accumbens being a crucial area for developing addictions to substances and behaviors. The addictive properties of gambling can perhaps be explained by the reward uncertainty that activates dopamine signaling in a pathological manner. Since reward-related learning is mediated by dopamine, it can be altered by dopaminergic medications, possibly leading to increased gambling behavior and a decreased impulse control. A causal relationship between the medications and GD seems likely, but the molecular mechanisms behind this association have not been fully described yet. More research is needed in order to fully outline the clinical picture of GD developing in patient groups with dopaminergic medications, and data are needed on the differentiation of risk in different compounds. In addition, very few interventional studies are available on the management of GD induced by dopaminergic medications. While GD overall can be treated, there is need for treatment studies testing the effectiveness of tapering of the medication or other gambling-specific treatment modalities in these patient groups.

Changing Gears - DBS For Dopaminergic Desensitization in Parkinson's Disease?

In Parkinson's disease, both motor and neuropsychiatric complications unfold as a consequence of both incremental striatal dopaminergic denervation and intensifying long-term dopaminergic treatment. Together, this leads to 'dopaminergic sensitization' steadily increasing motor and behavioral responses to dopaminergic medication that result in the detrimental sequalae of long-term dopaminergic treatment. We review the clinical presentations of 'dopaminergic sensitization', including rebound off and dyskinesia in the motor domain, and neuropsychiatric fluctuations and behavioral addictions with impulse control disorders and dopamine dysregulation syndrome in the neuropsychiatric domain. We summarize state-of-the-art deep brain stimulation, and show that STN-DBS allows dopaminergic medication to be tapered, thus supporting dopaminergic desensitization. In this framework, we develop our integrated debatable viewpoint of "changing gears", that is we suggest rethinking earlier use of subthalamic nucleus deep brain stimulation, when the first clinical signs of dopaminergic motor or neuropsychiatric complications emerge over the steadily progressive disease course. In this sense, subthalamic deep brain stimulation may help reduce longitudinal motor and neuropsychiatric symptom expression - importantly, not by neuroprotection but by supporting dopaminergic desensitization through postoperative medication reduction. Therefore, we suggest considering STN-DBS early enough before patients encounter potentially irreversible psychosocial consequences of dopaminergic complications, but importantly not before a patient shows first clinical signs of dopaminergic complications. We propose to consider neuropsychiatric dopaminergic complications as a new inclusion criterion in addition to established motor criteria, but this concept will require validation in future clinical trials. ANN NEUROL 2021.

Is there a Neurobiological Rationale for the Utility of the Iowa Gambling Task in Parkinson's Disease?

Up to 23% of newly diagnosed, non-demented, Parkinson’s disease (PD) patients experience deficits in executive functioning (EF). In fact, EF deficits may occur up to 39-months prior to the onset of motor decline. Optimal EF requires working memory, attention, cognitive flexibility, and response inhibition underlying appropriate decision-making. The capacity for making strategic decisions requires inhibiting imprudent decisions and are associated with noradrenergic and dopaminergic signaling in prefrontal and orbitofrontal cortex. Catecholaminergic dysfunction and the loss of noradrenergic and dopaminergic cell bodies early in PD progression in the aforementioned cortical areas likely contribute to EF deficits resulting in non-strategic decision-making. Thus, detecting these deficits early in the disease process could help identify a significant portion of individuals with PD pathology (14–60%) before frank motor impairment. A task to evaluate EF in the domain of non-strategic decision-making might be useful to indicate the moderate loss of catecholamines that occurs early in PD pathology prior to motor decline and cognitive impairment. In this review, we focus on the potential utility of the Iowa Gambling Task (IGT) for this purpose, given significant overlap between in loss of dopaminergic and noradrenergic cells bodies in early PD and the deficits in catecholamine function associated with decreased EF. As such, given the loss of catecholamines already well-underway after PD diagnosis, we evaluate the potential utility of the IGT to identify the risk of therapeutic non-compliance and a potential companion approach to detect PD in premotor stages.

Impulsivity Markers in Parkinsonian Subthalamic Single-Unit Activity

BACKGROUND

Impulsive-compulsive behaviors are common in Parkinson's disease (PD) patients. However, the basal ganglia dysfunctions associated with high impulsivity have not been fully characterized. The objective of this study was to identify the features associated with impulsive-compulsive behaviors in single neurons of the subthalamic nucleus (STN).

METHODS

We compared temporal and spectral features of 412 subthalamic neurons from 12 PD patients with impulsive-compulsive behaviors and 330 neurons from 12 PD patients without. Single-unit activities were extracted from exploratory microrecordings performed during deep brain stimulation (DBS) implant surgery in an OFF medication state.

RESULTS

Patients with impulsive-compulsive behaviors displayed decreased firing frequency during bursts and a larger fraction of tonic neurons combined with weaker beta coherence. Information carried by these features led to the identification of patients with impulsive-compulsive behaviors with an accuracy greater than 80%.

CONCLUSIONS

Impulsive-compulsive behaviors in PD patients are associated with decreased bursts in STN neurons in the OFF medication state. © 2021 International Parkinson and Movement Disorder Society.

Trait Impulsivity Is Independent of Mild Cognitive Impairment in a Parkinson's Disease Cohort

Introduction

Patients with Parkinson's disease (PD) commonly experience cognitive deficits and some also develop impulse control disorders (ICDs); however, the relationship between impulsivity and cognitive dysfunction remains unclear. This study investigated whether trait impulsivity associates with mild cognitive impairment (MCI), or is altered in a PD patient cohort with MCI.

Methods

A total of 302 patients with idiopathic PD were recruited sequentially from three Australian Movement Disorder clinics. Based on cognitive scores, participants were divided into two groups, one defined as having mild cognitive impairment (PD-MCI; n = 113) and the other with normal cognitive function (PD-C; n = 189). Trait impulsivity was evaluated using the Barrett Impulsiveness Scale 11 (BIS-11). Total impulsivity scores, as well as subscale scores, were compared between PD-C and PD-MCI groups.

Results

The PD-MCI cohort had significantly lower scores in all cognitive domains, and mirrored expected clinical differences in medication, motor symptoms, and disease duration, when compared to the PD-C cohort. Self-reported impulsivity was not significantly different between groups, nor was there a difference within first-order subscale scores: attention (p=0.137), cognitive instability (p=0.787), self-control (p=0.503), cognitive complexity (p=0.157), motor impulsivity (p=0.559), or perseverance (p=0.734) between the PD-MCI and PD-C groups.

Conclusions

These findings suggest that impulsive traits and behaviors are independent of changes in cognitive state and are not altered in PD patients with mild cognitive impairment.