Impulse control disorder in patients with Parkinson's disease under dopamine agonist therapy: a multicentre study

Host-diet-microbiota interplay in intestinal nutrition and health

The intestine is populated by a complex and dynamic assortment of microbes, collectively called gut microbiota, that interact with the host and contribute to its metabolism and physiology. Diet is considered a key regulator of intestinal microbiota, as ingested nutrients interact with and shape the resident microbiota composition. Furthermore, recent studies underscore the interplay of dietary and microbiota-derived nutrients, which directly impinge on intestinal stem cells regulating their turnover to ensure a healthy gut barrier. Although advanced sequencing methodologies have allowed the characterization of the human gut microbiome, mechanistic studies assessing diet-microbiota-host interactions depend on the use of genetically tractable models, such as Drosophila melanogaster. In this review, we first discuss the similarities between the human and fly intestines and then we focus on the effects of diet and microbiota on nutrient-sensing signaling cascades controlling intestinal stem cell self-renewal and differentiation, as well as disease. Finally, we underline the use of the Drosophila model in assessing the role of microbiota in gut-related pathologies and in understanding the mechanisms that mediate different whole-body manifestations of gut dysfunction.

Impulse Control Disorders in Parkinson's Disease: An Overview of Risk Factors, Pathogenesis and Pharmacological Management

Impulse control disorders in Parkinson's disease are relatively common drug-induced addictive behaviours that are usually triggered by the dopamine agonists pramipexole, ropinirole and rotigotine. This narrative review aimed to provide a comprehensive overview of the current knowledge of impulse control disorders in Parkinson's disease. We summarised the prevalence, clinical features, risk factors and potential underlying mechanisms of impulse control disorders in Parkinson's disease. Moreover, recent advances in behavioural and imaging characteristics and management strategies are discussed. Early detection as well as a tailored multidisciplinary approach, which typically includes careful adjustment of the dopaminergic therapy and the treatment of associated neuropsychiatric symptoms, are necessary. In some cases, a continuous delivery of levodopa via a pump or the dopamine D1 receptor agonist, apomorphine, can be considered. In selected patients without cognitive or speech impairment, deep brain stimulation of the subthalamic nucleus can also improve addictions. Finding the right balance of tapering dopaminergic dose (usually dopamine agonists) without worsening motor symptoms is essential for a beneficial long-term outcome.

Trait Impulsivity as a Feature of Parkinson's Disease Treatment and Progression

Heightened trait impulsivity in both subclinical and pathological senses is becoming increasingly recognised in Parkinson's disease (PD). Impulsive behaviours and impulse control disorders (ICDs) are a consequence of perturbation to the rewards pathway leading individuals to conduct activities in a repetitive, excessive, and maladaptive fashion. Commonly linked to PD, heightened trait impulsivity has been found to primarily manifest in the forms of hypersexuality, pathological gambling, compulsive shopping, and binge eating, all of which may significantly impact social and financial standing. Subsequent burden to quality of life for both individuals with PD and caregivers are common. Although risk factors and indicators for ICDs in PD are currently lacking, it is recognised that the condition is often precipitated by dopamine replacement therapies, primarily dopamine agonist administration. While this nonmotor symptom is being increasingly diagnosed in PD populations, it remains relatively elusive in comparison to its motor counterparts. Through discussion of impulsivity characteristics, neuroanatomy, and neurochemistry, in addition to reviewing existing research on the potential contributing factors to impulsivity in PD, this review highlights impulsivity as a significant and detrimental PD symptom. Thus, emphasising the imperative need to establish efficacious diagnostic tools and treatments.

Prognosis of impulse control disorders in Parkinson's disease: a prospective controlled study

BACKGROUND

The long-term prognosis of impulsive compulsive disorders (ICD) remains poorly studied in Parkinson's disease (PD).

OBJECTIVE

Evaluating the natural history of ICD and its impact on PD symptoms including cognition and treatment adjustments.

MATERIALS AND METHODS

We assessed PD patients at baseline (BL) with (BL-ICD+) or without (BL-ICD-) ICD despite dopamine agonist (DA) exposure of > 300 mg levodopa-equivalent daily dose for > 12 months at baseline and after more than two years of follow-up. ICD were assessed using the Ardouin's Scale of Behaviors in PD (ASBPD), cognition using the Mattis scale, and PD symptoms using the UPDRS score. Treatment adjustments, DA withdrawal-associated symptoms, and ICDs social consequences were recorded.

RESULTS

149 patients were included (78 cases and 71 controls), mean duration of follow-up was 4.4 ± 1 years. At baseline, psychiatric disorders were more common among BL-ICD + (42.3 vs 12.3% among BL-ICD-, p < 0.01). At follow-up, 53.8% of BL-ICD + were not ICD-free while 21.1% of BL-ICD- had developed ICD. BL-ICD + more frequently experienced akinesia (21.8 vs 8.5%, p = 0.043) and rigidity worsening (11.5 vs 1.4%, p = 0.019) following therapeutic modifications. Decision to decrease > 50% DA doses (12.8 vs 1.4%, p = 0.019) or to withdraw DA (19.2 vs 5.6%, p = 0.025) was more frequently considered among BL-ICD+ . At follow-up, the prevalence of cognitive decline was lower among BL-ICD + (19.2 vs 37.1%, p = 0.025).

CONCLUSION

ICDs were associated with increased psychiatric burden at baseline and better cognitive prognosis. Most patients were still showing ICDs at the follow-up visit, suggesting ICD to be considered as a chronic, neuropsychiatric disorder.

Comparison of the effectiveness, safety, and costs of anti-Parkinson drugs: A multiple-center retrospective study

AIMS

This study aimed to systematically compare the effectiveness, safety, and costs of different anti-Parkinson drugs (APDs).

METHODS

This is a multi-center study that retrospectively analyzed the data of 8420 outpatients with PD from 2014 to 2019 across 30 tertiary hospitals in China. The effectiveness was evaluated by changes in total dosages of APDs, normalized by levodopa equivalent dose (LED) and presented as ΔLEDs; levodopa equivalent dose cost (LEDc) represented the daily cost of APDs; and newly added diagnostics were represented as APDs-related adverse events.

RESULTS

A total of 384 patients with eligible medical records for three consecutive years were enrolled. Patients treated with carbidopa/levodopa or levodopa/benserazide had significantly lower mean ΔLEDs than other groups (p < 0.01), followed by pramipexole and selegiline. The piribedil group had the highest ΔLEDs, with mean differences of 112.56-355.04 mg compared to other groups (p < 0.01). Meanwhile, LEDc in the levodopa/benserazide, carbidopa/levodopa, and piribedil groups were significantly lower than those in pramipexole or selegiline groups ($0.088-0.135/day for levodopa/benserazide; $0.070-0.126/day for carbidopa/levodopa; $0.112-0.138/day for piribedil; $0.290-0.332/day for pramipexole; $0.229-0.544/day for selegiline; p < 0.01). Patients with piribedil had more adverse events, with an incidence rate of 35.7%, followed by levodopa/benserazide (25.6%), selegiline (23.5%), carbidopa/levodopa (23.3%), and pramipexole (16.4%). Pramipexole showed a lower incidence rate of adverse events than piribedil, including neuropsychiatric symptoms (p = 0.006), headache/dizziness (p = 0.016), and gastrointestinal symptoms (p = 0.031).

CONCLUSIONS

Carbidopa/levodopa or levodopa/benserazide might exhibit better clinical improvement with less medical cost, while piribedil presented less clinical improvement but a higher risk of headache/dizziness, gastrointestinal, and neuropsychiatric symptoms.

Impulse control disorders in Parkinson's disease patients treated with pramipexole and ropinirole: a systematic review and meta-analysis

BACKGROUND

This analysis is the first systematic review and meta-analysis assessing occurrences of ICD in PD patients treated with oral DAs: ropinirole (ROP) and pramipexole (PRX). This study compares the two oral DAs to a transdermal patch, rotigotine (RTG).

METHODS

We performed an extensive systematic search for eligible studies from PubMed, Embase, Cochrane Library, and Google Scholar. The data was analyzed by various software, including EndNote, Rayyan, PRISM, and RevMan. Two studies incorporating 658 patients collectively were assessed.

RESULTS

This meta-analysis shows a significant correlation between the usage of PRX (25.3%) or ROP (21.8%) and the development of ICD in PD patients. Compared to the transdermal patch, RTG, PRX was found to have a significant relative risk (P < 0.0001) of 3.46 (95% CI 2.07-5.76), and ROP was found to have a significant relative risk (P < 0.0001) of 2.98 (95% CI 1.77-5.02). The data collected shows RTG is approximately three times less likely to cause ICDs than oral PRX and ROP.

CONCLUSION

The present investigation provides insight into ICD occurrences with PRX, ROP, and RTG to allow physicians to make more informed decisions on risk versus reward when deciding how to treat a PD patient with these drugs. However, related to various disclosed limitations, our conclusion cannot provide definitive practice protocols.

Altered Impulsivity Across Drug-Naïve Parkinsonism, Isolated Rapid Eye Movement Sleep Behavior Disorder, and Their High-Risk Relatives

OBJECTIVE

To determine multidimensional impulsivity levels across different early stages of α-synucleinopathy.

METHODS

This cross-sectional study investigated motor and decisional impulsivity levels using a panel of computerized tasks among drug-naïve parkinsonism patients, isolated/idiopathic rapid eye movement sleep behavior disorder (iRBD) patients and their first-degree relatives (iRBD-FDRs), and control participants. Trait impulsivity and impulse control behaviors were assessed by self-reported questionnaires.

RESULTS

A total of 27 drug-naïve parkinsonism patients, 157 iRBD patients, 66 iRBD-FDRs, and 82 control participants were recruited. Parkinsonism and iRBD patients had fewer numbers of extracted beads in beads task 1 and 2 (both p < 0.001), and a higher rate of irrational choice in task 1 (p = 0.046) before making decisions, and fewer numbers of pumps of unexploded blue balloons in the balloon analog risk task (p = 0.004) than control participants, indicating a higher level of reflection impulsivity and a lower level of risk taking, respectively. iRBD patients had more no-go errors in the go/no-go task than control participants (padjusted  = 0.036), suggesting a higher level of motor impulsivity. iRBD-FDRs with dream-enactment behaviors had fewer numbers of extracted beads (p = 0.047) in beads task 2 than FDRs without dream-enactment behaviors, suggesting a possible higher level of reflection impulsivity.

INTERPRETATION

A complex construct of altered impulsivity with decreased risk taking, but increased reflection and motor impulsivity, has already occurred at the prodromal and early stages of α-synucleinopathy, which have implications for underlying pathophysiology and clinical management of α-synucleinopathy, especially for impulse control behaviors upon dopaminergic drug treatment. ANN NEUROL 2024;95:544-557.

Impulse Control Disorders in Parkinson's Disease and Atypical Parkinsonian Syndromes-Is There a Difference?

BACKGROUND AND OBJECTIVES

Impulse control disorders (ICDs) are characterized by potentially harmful actions resulting from disturbances in the self-control of emotions and behavior. ICDs include disorders such as gambling, hypersexuality, binge eating, and compulsive buying. ICDs are known non-motor symptoms in Parkinson's disease (PD) and are associated primarily with the use of dopaminergic treatment (DRT) and especially dopamine agonists (DA). However, in atypical parkinsonism (APS), such as progressive supranuclear palsy (PSP) or multiple system atrophy (MSA), there are only single case reports of ICDs without attempts to determine the risk factors for their occurrence. Moreover, numerous reports in the literature indicate increased impulsivity in PSP. Our study aimed to determine the frequency of individual ICDs in APS compared to PD and identify potential factors for developing ICDs in APS.

MATERIALS AND METHODS

Our prospective study included 185 patients with PD and 35 with APS (27 patients with PSP and 9 with MSA) hospitalized between 2020 and 2023 at the Neurological Department of University Central Hospital in Katowice. Each patient was examined using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP) to assess ICDs. Additionally, other scales were used to assess the advancement of the disease, the severity of depression, and cognitive impairment. Information on age, gender, age of onset, disease duration, and treatment used were collected from medical records and patient interviews.

RESULTS

ICDs were detected in 23.39% of patients with PD (including binge eating in 11.54%, compulsive buying in 10.44%, hypersexuality in 8.79%, and pathological gambling in 4.40%), in one patient with MSA (hypersexuality and pathological gambling), and in 18.52% of patients with PSP (binge eating in 3.70%, compulsive buying in 7.41%, and hypersexuality in 11.11%). We found no differences in the frequency of ICDs between individual diseases (p = 0.4696). We confirmed that the use of higher doses of DA and L-dopa in patients with PD, as well as a longer disease duration and the presence of motor complications, were associated with a higher incidence of ICDs. However, we did not find any treatment effect on the incidence of ICDs in APS.

CONCLUSIONS

ICDs are common and occur with a similar frequency in PD and APS. Well-described risk factors for ICDs in PD, such as the use of DRT or longer disease duration, are not fully reflected in the risk factors for ICDs in APS. This applies especially to PSP, which, unlike PD and MSA, is a tauopathy in which, in addition to the use of DRT, other mechanisms related to the disease, such as disorders in neuronal loops and neurotransmitter deficits, may influence the development of ICDs. Further prospective multicenter studies recruiting larger groups of patients are needed to fully determine the risk factors and mechanisms of ICD development in APS.

Management of Impulse Control and Related Disorders in Parkinson's Disease: An Expert Consensus

BACKGROUND

Impulse-control and related behavioral disorders (ICBDs) significantly impact the lives of Parkinson's disease (PD) patients and caregivers, with lasting consequences if undiagnosed and untreated. While ICBD pathophysiology and risk factors are well-studied, a standardized severity definition and treatment evidence remain elusive.

OBJECTIVE

This work aimed to establish international expert consensus on ICBD treatment strategies. To comprehensively address diverse treatment availabilities, experts from various continents were included.

METHODS

From 2021 to 2023, global movement disorders specialists engaged in a Delphi process. A core expert group initiated surveys, involving a larger panel in three iterations, leading to refined severity definitions and treatment pathways.

RESULTS

Experts achieved consensus on defining ICBD severity, emphasizing regular PD patient screenings for early detection. General treatment recommendations focused on continuous monitoring, collaboration with significant others, and seeking specialist advice for legal or financial challenges. For mild to severe ICBDs, gradual reduction in dopamine agonists was endorsed, followed by reductions in other PD medications. Second-line treatment strategies included diverse approaches like reversing the last medication change, cognitive behavior therapy, subthalamic nucleus deep brain stimulation, and specific medications like quetiapine, clozapine, and antidepressants. The panel reached consensus on distinct treatment pathways for punding and dopamine dysregulation syndrome, formulating therapy recommendations. Comprehensive discussions addressed management strategies for the exacerbation of either motor or non-motor symptoms following the proposed treatments.

CONCLUSION

The consensus offers in-depth insights into ICBD management, presenting clear severity criteria and expert consensus treatment recommendations. The study highlights the critical need for further research to enhance ICBD management. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Dopamine agonist serum concentrations and impulse control disorders in Parkinson's disease

BACKGROUND AND PURPOSE

Impulse control disorders (ICDs) are common among Parkinson's disease patients using dopamine agonists. We wanted to determine whether ICD patients have higher dopamine agonist serum concentrations than those without any sign of ICD.

METHODS

Patients who used either pramipexole or ropinirole depot once daily were screened for ICDs using the validated Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale. Those who scored above the cut-off for one or more of the four defined ICDs (gambling, compulsive sexual behavior, compulsive shopping, and binge-eating) were compared in a case-control study to patients who scored zero points (no evidence of ICD) on the same items. They were examined clinically and evaluated using relevant scales. Three blood samples were taken on the same day: before daily dose, and then 6 and 12 h later.

RESULTS

Forty-six patients were included: 19 ICD-positive and 27 controls. Ropinirole serum concentrations 6 h after daily intake (Cmax ) were higher in the case group compared to the control group, as was the daily ropinirole dosage. No differences were observed in serum concentrations, dosage or total drug exposure for pramipexole. Disease duration and length of dopamine agonist treatment was significantly longer among ICD patients for ropinirole, but not for pramipexole.

CONCLUSIONS

The use of pramipexole may in itself confer high ICD risk, whereas ICDs among ropinirole users depend more on serum concentration and drug exposure. The pharmacokinetic properties of ropinirole make it challenging to predict its effects on patients, which supports the need for therapeutic drug monitoring to reduce risk of ICD.

Acupuncture therapy for Parkinson's disease: a case report demonstrating symptomatic improvement without medication

Background

Parkinson's disease (PD) often necessitates immediate medical intervention following diagnosis. In recent years, there has been a noticeable increase in clinical investigations assessing the efficacy of acupuncture in PD, with many studies reporting positive outcomes. Ethical guidelines commonly endorse pharmaceutical therapies for PD, leading ongoing research to combine acupuncture with standard drug-based treatments. At present, there is a conspicuous absence of dedicated clinical research exclusively examining the independent impact of acupuncture on PD treatment.

Case

In a clinical observation, we documented a case involving a 75-year-old male displaying progressive, characteristic PD symptoms, including evident limb tremors, rigidity, bradykinesia, fatigue, and additional non-motor symptoms. The patient received a confirmed diagnosis of PD. Due to the refusal of the patient to take medication, we exclusively administered acupuncture therapy. The outcomes indicated a noteworthy enhancement in the clinical symptoms of the patient solely through acupuncture intervention.

Conclusion

This case affirms that using acupuncture in isolation significantly improved both the motor and non-motor symptoms in the patient. Acupuncture could potentially serve as an alternative therapy for patients who decline or are intolerant to anti-Parkinson drugs. However, further studies are needed to assess its long-term efficacy. This case report obtained approval from the Ethics Committee of the First Affiliated Hospital of Guangzhou University of Chinese Medicine (Ethics number: K-2023-127).

Impulse control and related behavioral disorders (ICRD) in Idiopathic Parkinson's Disease treated with different dopamine agonists in Hong Kong: Is any dopamine agonist better?

Objective

To assess the incidence of Impulse control and related behavioral disorders (ICRD) in Chinese Idiopathic Parkinson Disease (IPD) patients treated with different dopamine agonists (DA), and their clinical characteristics and associated risk factors.

Methods

This was an observational cohort study based on clinical interviews and medical records of IPD patients treated with DA for >6 months in three hospitals in Hong Kong. The short version of Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP-S) was used to screen for ICRD. ICRD incidence among different DA, clinical characteristics and risk factors were examined.

Results

Incidence of ICRD was analyzed in 311 patients taking their first, single DA. 43 patients (13.8 %) developed ICRD. The mean duration of IPD was 8.5 ± 5.6 years and median HY stage was 2.5. Bromocriptine and rotigotine users had lower ICRD incidence rate. Both pramipexole [adjusted HR 7.28 (2.46-21.54), p < 0.001] and ropinirole [adjusted HR 6.53 (2.67-15.99), p < 0.001] were independently associated with higher risk of ICRD compared to bromocriptine in multivariate analysis. Similarly, pramipexole and ropinirole appeared to carry higher risk compared to rotigotine but did not reach statistical significance. Male [adjusted HR 2.24 (1.07-4.72), p = 0.033], younger IPD onset [adjusted HR 2.99 (1.44-6.19) for onset < 50 year, p = 0.003] and history of psychiatric disorders [adjusted HR 2.80 (1.39-5.62), p = 0.004] were other independent risk factors.

Conclusion

Bromocriptine and probably rotigotine carried a lower ICRD risk compared to pramipexole and ropinirole.

Different impulse control disorder evolution patterns and white matter microstructural damage in the progression of Parkinson's disease

Background

The course of impulse control disorders (ICD) varies in the early stage of Parkinson's disease (PD).

Aim

We aimed to delineate the association between the evolution pattern of ICD and the progression of PD.

Methods

A total of 321 de novo PD patients from the Parkinson's Progression Markers Initiative database were included. Patients were followed up for a mean of 6.8 years and were classified into different groups according to the evolution patterns of ICD. Disease progression was compared among groups using survival analysis, in which the endpoint was defined as progression to Hoehn and Yahr stage 3 or higher for motor progression and progression to mild cognitive impairment for cognitive decline. In the fourth year of follow-up, four types of ICD evolution patterns were identified: (1) non-ICD-stable (68.2%), a patient who is consistently free of ICD; (2) late-ICD (14.6%), ICD developed during the follow-up of patients; (3) ICD-stable (11.5%), patients showed persistent ICD; and (4) ICD-reversion (5.6%), baseline ICD disappeared during the follow-up of patients with ICD.

Results

The ICD-reversion type shows daily life non-motor symptoms [Movement Disorder Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS) part I], daily life motor symptoms (MDS-UPDRS part II), rapid eye movement sleep behavior disorder, and anxiety symptoms has a greater impact. PD patients with different ICD evolution patterns had different changes in white matter microstructure at the onset of the disease. Those relevant brain regions are involved in ICD and non-motor functions.

Conclusion

Four early ICD evolution patterns are identified in de novo PD, with different prognoses and brain white matter microstructural damage patterns, and they may predict motor progression and cognitive decline in PD patients.

Accentuated Paralimbic and Reduced Mesolimbic D2/3-Impulsivity Associations in Parkinson's Disease

Impulsivity is a behavioral trait that is elevated in many neuropsychiatric disorders. Parkinson's disease (PD) patients can exhibit a specific pattern of reward-seeking impulsive-compulsive behaviors (ICBs), as well as more subtle changes to generalized trait impulsivity. Prior studies in healthy controls (HCs) suggest that trait impulsivity is regulated by D2/3 autoreceptors in mesocorticolimbic circuits. While altered D2/3 binding is noted in ICB+ PD patients, there is limited prior assessment of the trait impulsivity-D2/3 relationship in PD, and no prior direct comparison with patterns in HCs. We examined 54 PD (36 M; 18 F) and 31 sex- and age-matched HC (21 M; 10 F) subjects using [18F]fallypride, a high-affinity D2/3 receptor ligand, to measure striatal and extrastriatal D2/3 nondisplaceable binding potential (BPND). Subcortical and cortical assessment exclusively used ROI or exploratory-voxelwise methods, respectively. All completed the Barratt Impulsiveness Scale, a measure of trait impulsivity. Subcortical ROI analyses indicated a negative relationship between trait impulsivity and D2/3 BPND in the ventral striatum and amygdala of HCs but not in PD. By contrast, voxelwise methods demonstrated a positive trait impulsivity-D2/3 BPND correlation in ventral frontal olfactocentric-paralimbic cortex of subjects with PD but not HCs. Subscale analysis also highlighted different aspects of impulsivity, with significant interactions between group and motor impulsivity in the ventral striatum, and attentional impulsivity in the amygdala and frontal paralimbic cortex. These results suggest that dopamine functioning in distinct regions of the mesocorticolimbic circuit influence aspects of impulsivity, with the relative importance of regional dopamine functions shifting in the neuropharmacological context of PD.SIGNIFICANCE STATEMENT The biological determinants of impulsivity have broad clinical relevance, from addiction to neurodegenerative disorders. Here, we address biomolecular distinctions in Parkinson's disease. This is the first study to evaluate a large cohort of Parkinson's disease patients and age-matched healthy controls with a measure of trait impulsivity and concurrent [18F]fallypride PET, a method that allows quantification of D2/3 receptors throughout the mesocorticolimbic network. We demonstrate widespread differences in the trait impulsivity-dopamine relationship, including (1) loss of subcortical relationships present in the healthy brain and (2) emergence of a new relationship in a limbic cortical area. This illustrates the loss of mechanisms of behavioral regulation present in the healthy brain while suggesting a potential compensatory response and target for future investigation.

Effects of non-invasive brain stimulation over supplementary motor area in people with Parkinson's disease: a protocol for a systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

Individuals with Parkinson's disease (PD) often experience initial hesitation, slowness of movements, decreased balance and impaired standing ability, which can significantly impact their independence. Transcranial magnetic stimulation and transcranial direct current stimulation are two widely used and promising non-invasive brain stimulation (NIBS) modalities for treating PD. The supplementary motor area (SMA), associated with motor behaviour and processing, has received increasing attention as a potential stimulation target to alleviate PD-related symptoms. However, the data on NIBS over SMA in PD individuals are inconsistent and has not been synthesised. In this article, we will review the evidence for NIBS over SMA in PD individuals and evaluate its efficacy in improving PD function.

METHOD AND ANALYSIS

Randomised controlled clinical trials comparing the effects of NIBS and sham stimulation on motor function, activities of daily living and participation for people with PD will be included. A detailed computer-aided search of the literature will be performed from inception to February 2023 in the following databases: PubMed, EMBASE, Physiotherapy Evidence Database (PEDro), Web of Science (WOS) and The Chinese National Knowledge Infrastructure (CNKI). Two independent reviewers will screen articles for relevance and methodological validity. The PEDro scale will be used to evaluate the risk of bias of selected studies. Data from included studies will be extracted by two independent reviewers through a customised, preset data extraction sheet.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review. The study's findings will be presented at scientific meetings and published in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42023399945.

Comparative efficacy and safety of adjunctive drugs to levodopa for fluctuating Parkinson's disease - network meta-analysis

It remains unclear which adjunctive drug for Parkinson's disease (PD) in combination with levodopa is more effective, tolerable, and safe. We aimed to compare the efficacy, tolerability, and safety among anti-PD drugs from several classes in patients with fluctuating PD who received levodopa through network meta-analysis (NMA). Twelve anti-PD drugs belonging to 4 different drug classes (dopamine agonists, monoamine oxidase type B inhibitors, catechol-O-methyl transferase inhibitors, and an adenosine A2A receptor antagonist) were selected. We systematically searched PubMed, Embase, and the Cochrane Library for eligible randomized controlled trials (RCTs) comparing placebo with anti-PD drug or among anti-PD drugs in patients with PD who experienced motor fluctuations or wearing-off and received levodopa. We included 54 RCTs in the analysis. The NMA was performed under a frequentist framework using a random-effects model. The efficacy outcome was change in daily off-time, and the tolerability outcome was discontinuation due to all causes. Safety outcomes included discontinuation due to adverse events (AEs) and the incidence of AEs, dyskinesia, hallucination, and orthostatic hypotension. According to the surface under the cumulative ranking curve (SUCRA) in the NMA, ropinirole transdermal patch (SUCRA, 0.861) ranked the highest in efficacy, followed by pramipexole (0.762), ropinirole extended release (ER) (0.750), and safinamide (0.691). In terms of tolerability, ropinirole (0.954) ranked the highest, followed by pramipexole (0.857), safinamide (0.717), and ropinirole ER (0.708). Each anti-PD drug had different SUCRA ranking profiles for the safety outcomes. These findings suggest that ropinirole, pramipexole, and safinamide are well-balanced anti-PD drugs that satisfy both efficacy and tolerability outcomes.

The pharmacological management of the behavioral aspects of Parkinson's disease: an update

INTRODUCTION

Behavioural symptoms are common manifestations of Parkinson's disease and include depression, anxiety, impulse control disorders, hallucinations, psychosis, and cognitive dysfunction. They remain inadequately addressed in many patients despite their relevance for quality of life and disability. This applies also to impulse control disorders where the most common approach in recent literature is to refrain from using dopamine agonists without consideration about their potential benefit on motor complications.

AREAS COVERED

We conducted a narrative review searching for articles on behavioral symptoms in Parkinson disease and selected those which included involved neurotransmitters such as dopamine, noradrenaline, serotonin, acetylcholine. We specifically focused our search on open-label and randomized double-blind studies and biomarkers which could best characterize these clinical manifestations.

EXPERT OPINION

Management of Parkinson disease behavioural manifestations lacks clear guidelines and standardized protocols beside general suggestions of dose adjustments in dopamine replacement therapy and use of antidepressants or antipsychotic drugs with little consideration of patients' age, sex, comorbidities, and motor status. We suggest a pragmatic approach which includes education of affected patients and caring people, dealing with complex cases by experienced multidisciplinary teams, use of cognitive behavioural therapy, and psychological counselling to complement drug treatment.

Impulse Control Disorders in the Polish Population of Patients with Parkinson's Disease

Background and Objectives: Parkinson's disease (PD) is one of the most common neurodegenerative diseases in the world. It is characterized by the presence of not only typical motor symptoms but also several less known and aware non-motor symptoms (NMS). The group of disorders included in the NMS is Impulse Control Disorders (ICDs). ICDs are a group of disorders in which patients are unable to resist temptations and feel a strong, pressing desire for specific activities such as gambling, hypersexuality, binge eating, and compulsive buying. The occurrence of ICDs is believed to be associated primarily with dopaminergic treatment, with the use of dopamine agonists (DA), and to a lesser extent with high doses of L-dopa. The aim of our study was to develop a profile of Polish ICDs patients and assess the frequency of occurrence of ICDs, as well as determine the risk factors associated with these disorders against the background of the PD population from other countries. Materials and Methods: Our prospective study included 135 patients with idiopathic PD who were hospitalized between 2020 and 2022 at the Neurological Department of University Central Hospital in Katowice. In the assessment of ICDs, we used the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP). Other scales with which we assessed patients with PD were as follows: MDS-UPDRS part III and modified Hoehn-Yahr staging. Clinical data on age, gender, disease duration and onset, motor complications, and medications were collected from electronic records. Results: ICDs were detected in 27.41% of PD patients (binge eating in 12.59%, hypersexuality in 11.11%, compulsive buying in 10.37%, and pathological gambling occurred in only 5.19% of patients. In total, 8.89% had two or more ICDs). The major finding was that ICDs were more common in patients taking DA than in those who did not use medication from this group (83.78% vs. 54.07%, respectively; p = 0.0015). Patients with ICDs had longer disease duration, the presence of motor complications, and sleep disorders. An important finding was also a very low detection of ICDs in a routine medical examination; only 13.51% of all patients with ICDs had a positive medical history of this disorder. Conclusions: ICDs are relatively common in the population of Polish PD patients. The risk factors for developing ICDs include longer duration of the disease, presence of motor complications, sleep disorders, and use of DA and L-dopa. Due to the low detectability of ICDs in routine medical history, it is essential for physicians to pay more attention to the possibility of the occurrence of these symptoms, especially in patients with several risk factors. Further prospective studies on a larger group of PD patients are needed to establish a full profile of Polish PD patients with ICDs.

Pathophysiology and Neuroimmune Interactions Underlying Parkinson's Disease and Traumatic Brain Injury

Parkinson's disease (PD) is a progressive neurodegenerative disorder clinically defined by motor instability, bradykinesia, and resting tremors. The clinical symptomatology is seen alongside pathologic changes, most notably the loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the accumulation of α-synuclein and neuromelanin aggregates throughout numerous neural circuits. Traumatic brain injury (TBI) has been implicated as a risk factor for developing various neurodegenerative diseases, with the most compelling argument for the development of PD. Dopaminergic abnormalities, the accumulation of α-synuclein, and disruptions in neural homeostatic mechanisms, including but not limited to the release of pro-inflammatory mediators and the production of reactive oxygen species (ROS), are all present following TBI and are closely related to the pathologic changes seen in PD. Neuronal iron accumulation is discernable in degenerative and injured brain states, as is aquaporin-4 (APQ4). APQ4 is an essential mediator of synaptic plasticity in PD and regulates edematous states in the brain after TBI. Whether the cellular and parenchymal changes seen post-TBI directly cause neurodegenerative diseases such as PD is a point of considerable interest and debate; this review explores the vast array of neuroimmunological interactions and subsequent analogous changes that occur in TBI and PD. There is significant interest in exploring the validity of the relationship between TBI and PD, which is a focus of this review.

Identifying NFKB1, STAT3, and CDKN1A as Baicalein's Potential Hub Targets in Parkinson's Disease-related α-synuclein-mediated Pathways by Integrated Bioinformatics Strategies

BACKGROUND

The overexpression, accumulation, and cell-to-cell transmission of α-synuclein leads to the deterioration of Parkinson's disease (PD). Previous studies suggest that Baicalein (BAI) can bind to α-synuclein and inhibit α-synuclein aggregation and secretion. However, it is still unclear whether BAI can intervene with the pathogenic molecules in α-synuclein-mediated PD pathways beyond directly targeting α-synuclein per se.

METHODS

This study aimed to systematically investigate BAI's potential targets in PD-related A53T mutant α-synuclein-mediated pathways by integrating data mining, network pharmacological analysis, and molecular docking simulation techniques.

RESULTS

The results suggest that BAI may target genes that are dysregulated in synaptic transmission, vesicle trafficking, gene transcription, protein binding, extracellular matrix formation, and kinase activity in α-synucleinmediated pathways. NFKB1, STAT3, and CDKN1A are BAI's potential hub targets in these pathways.

CONCLUSION

Our findings highlight BAI's potentiality to modulate α-synuclein-mediated pathways beyond directly targeting α-synuclein per se.

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.

Neural correlates of impulsive compulsive behaviors in Parkinson's disease: A Japanese retrospective study

BACKGROUND

Impulsive compulsive behaviors (ICBs) often disturb patients with Parkinson's Disease (PD), of which impulse control disorder (ICD) and dopamine dysregulation syndrome (DDS) are two major subsets. The nucleus accumbens (NAcc) is involved in ICB; however, it remains unclear how the NAcc affects cortical function and defines the different behavioral characteristics of ICD and DDS.

OBJECTIVES

To identify the cortico-striatal network primarily involved in ICB and the differences in these networks between patients with ICD and DDS using structural and resting-state functional magnetic resonance imaging.

METHODS

Patients with PD were recruited using data from a previous cohort study and divided into those with ICB (ICB group) and without ICB (non-ICB group) using the Japanese version of the Questionnaire for Impulsive Compulsive Disorders in Parkinson's Disease (J-QUIP). From these two groups, we extracted 37 pairs matched for age, sex, disease duration, and levodopa equivalent daily dose of dopamine agonists. Patients with ICB were further classified as having ICD or DDS based on the J-QUIP subscore. General linear models were used to compare gray matter volume and functional connectivity (FC) of the NAcc, caudate, and putamen between the ICB and non-ICB groups and between patients with ICD and those with DDS.

RESULTS

We found no significant differences in gray matter volumebetween the ICB and non-ICB groups or between patients with ICD and those with DDS. Compared with the non-ICB group, the FC of the right NAcc in the ICB group was lower in the bilateral ventromedial prefrontal cortex and higher in the left middle occipital gyrus. Furthermore, patients with DDS showed higher FC between the right putamen and left superior temporal gyrus and higher FC between the left caudate and bilateral middle occipital gyrus than patients with ICD. In contrast, patients with ICD exhibited higher FC between the left NAcc and the right posterior cingulate cortex than patients with DDS.

CONCLUSIONS

The functionally altered network between the right NAcc and ventromedial prefrontal cortex was associated with ICB in PD. In addition, the surrounding cortico-striatal networks may differentiate the behavioral characteristics of patients with ICD and those with DDS.

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.

Should patients with Parkinson’s disease only visit a neurologist’s office? - a narrative review of neuropsychiatric disorders among people with Parkinson’s disease

Introduction: Parkinson’s disease is a neurodegenerative disease that is often accompanied by disorders such as depression, psychotic disorders, cognitive disorders, anxiety disorders, sleep disorders, impulse control disorders. The aim of the study was to review the literature and present the characteristics of neuropsychiatric disorders occurring in people suffering from Parkinson’s disease, with the specification of the above-mentioned disorders.

Material and method: The literature available on the PubMed platform from 1986 to 2022 was reviewed using the following keywords: Parkinson’s disease, depression, anxiety disorders, psychotic disorders, sleep disorders, cognitive disorders, impulse control disorders. Original studies, reviews, meta-analyzes and internet sources were analyzed.

Results: The above-mentioned neuropsychiatric disorders appear with different frequency among people suffering from Parkinson’s disease and occur at different times of its duration or even precede its onset for many years. The non-motor symptoms in the form of depressed mood, energy loss or changes in the rhythm of the day may result in a delay of appropriate therapy and thus in complications. Neuropathological changes in the course of Parkinson’s disease as well as dopaminergic drugs used in its therapy influence the development of neuropsychiatric disorders.

Conclusions: In order to avoid misdiagnosis, practitioners should use, e.g. scales intended for patients with Parkinson’s disease. To prevent the consequences of the aforementioned disease entities, methods of early diagnosis, determination of risk factors and standardization of the treatment process must be determined. Consistent care for patients with Parkinson’s disease is significant, not only in the neurological field, but also in the psychiatric one.

Management of psychiatric and cognitive complications in Parkinson's disease

Neuropsychiatric symptoms (NPSs) such as affective disorders, psychosis, behavioral changes, and cognitive impairment are common in Parkinson's disease (PD). However, NPSs remain under-recognized and under-treated, often leading to adverse outcomes. Their epidemiology, presentation, risk factors, neural substrate, and management strategies are incompletely understood. While psychological and psychosocial factors may contribute, hallmark PD neuropathophysiological changes, plus the associations between exposure to dopaminergic medications and occurrence of some symptoms, suggest a neurobiological basis for many NPSs. A range of psychotropic medications, psychotherapeutic techniques, stimulation therapies, and other non-pharmacological treatments have been studied, are used clinically, and are beneficial for managing NPSs in PD. Appropriate management of NPSs is critical for comprehensive PD care, from recognizing their presentations and timing throughout the disease course, to the incorporation of different therapeutic strategies (ie, pharmacological and non-pharmacological) that utilize a multidisciplinary approach.

Amphetamine-induced dopamine release and impulsivity in Parkinson's disease

Impulsive-compulsive behaviours manifest in a substantial proportion of subjects with Parkinson's disease. Reduced ventral striatum dopamine receptor availability, and increased dopamine release is noted in patients with these symptoms. Prior studies of impulsivity suggest that midbrain D2 autoreceptors regulate striatal dopamine release in a feedback inhibitory manner, and in healthy populations, greater impulsivity is linked to poor proficiency of this inhibition. This has not been assessed in a Parkinson's disease population. Here, we applied 18F-fallypride PET studies to assess striatal and extrastriatal D2-like receptor uptake in a placebo-controlled oral dextroamphetamine sequence. We hypothesized that Parkinson's disease patients with impulsive-compulsive behaviours would have greater ventral striatal dopaminergic response to dextroamphetamine, and that an inability to attenuate ventral striatal dopamine release via midbrain D2 autoreceptors would underlie this response. Twenty patients with Parkinson's disease (mean age = 64.1 ± 5.8 years) both with (n = 10) and without (n = 10) impulsive-compulsive behaviours, participated in a single-blind dextroamphetamine challenge (oral; 0.43 mg/kg) in an OFF dopamine state. All completed PET imaging with 18F-fallypride, a high-affinity D2-like receptor ligand, in the placebo and dextroamphetamine state. Both voxelwise and region of interest analyses revealed dextroamphetamine-induced endogenous dopamine release localized to the ventral striatum, and the caudal-medial orbitofrontal cortex. The endogenous dopamine release observed in the ventral striatum correlated positively with patient-reported participation in reward-based behaviours, as quantified by the self-reported Questionnaire for Impulsivity in Parkinson's disease Rating Scale. In participants without impulsive-compulsive behaviours, baseline midbrain D2 receptor availability negatively correlated with ventral striatal dopamine release; however, this relationship was absent in those with impulsive-compulsive behaviours. These findings emphasize that reward-based behaviours in Parkinson's disease are regulated by ventral striatal dopamine release, and suggest that loss of inhibitory feedback from midbrain autoreceptors may underlie the manifestation of impulsive-compulsive behaviours.

Impulse control disorders in hyperprolactinemic patients on dopamine agonist therapy

Dopamine agonists (DAs) represent a mainstay of therapy for hyperprolactinemia and prolactinomas. The widespread use of DAs, including bromocriptine, cabergoline and (in some countries) quinagolide, has led to the emergence and recognition of impulse control disorders (ICDs) that may occur in association with DA therapy.Such ICDs include pathological gambling, compulsive shopping, hypersexuality and punding (the performance of repetitive tasks), among others. These manifestations can lead to substantial harms to patients and their families, if left undiagnosed and untreated. Several risk factors that may increase the risk of ICDs have been proposed, including younger age, male gender, smoking and alcohol use and history of depression.The diagnosis of ICDs in hyperprolactinemic patients treated with DAs requires a high index of suspicion and a systematic approach, using available screening questionnaires. However, it should be noted that available test instruments, including questionnaires and computerized tasks, have not been validated specifically in hyperprolactinemic patients. Hyperprolactinemic patients who develop ICDs should be withdrawn from DA therapy or, at a minimum, undergo a DA dose reduction, and considered for psychiatric consultation and cognitive behavioral therapy. However, the role of psychopharmacotherapy in hyperprolactinemic patients with ICDs remains incompletely characterized.Patient counseling regarding the risk of ICDs occurring in association with DA therapy, early detection and prompt intervention may mitigate potential harms associated with ICDs. Additional studies are needed to fully characterize risk factors, underlying mechanisms and identify effective therapies for ICDs in patients with hyperprolactinemia receiving DAs.

Cognitive Behavioral Therapy Plus a Serious Game as a Complementary Tool for a Patient With Parkinson Disease and Impulse Control Disorder: Case Report

Background

Impulse control disorders (ICDs) are commonly developed among patients who take dopamine agonist drugs as a treatment for Parkinson disease (PD). Gambling disorder and hypersexuality are more frequent in male patients with PD, with a prevalence over 4% in dopamine agonists users. Although impulsive-compulsive behaviors are related to antiparkinsonian medication, and even though ICD symptomatology, such as hypersexuality, often subsides when the dopaminergic dose is reduced, sometimes ICD persists in spite of drug adjustment. Consequently, a multidisciplinary approach should be considered to address these comorbidities and to explore new forms of complementary interventions, such as serious games or therapies adapted to PD.

Objective

The aim of this study is to present the case of a patient with ICD (ie, hypersexuality) triggered by dopaminergic medication for PD. A combined intervention was carried out using cognitive behavioral therapy (CBT) for ICD adapted to PD, plus an intervention using a serious game—e-Estesia—whose objective is to improve emotion regulation and impulsivity. The aim of the combination of these interventions was to reduce the harm of the disease.

Methods

After 20 CBT sessions, the patient received the e-Estesia intervention over 15 sessions. Repeated measures, before and after the combined intervention, were administered to assess emotion regulation, general psychopathology, and emotional distress and impulsivity.

Results

After the intervention with CBT techniques and e-Estesia, the patient presented fewer difficulties to regulate emotion, less emotional distress, and lower levels of impulsivity in comparison to before the treatment. Moreover, the frequency and severity of the relapses also decreased.

Conclusions

The combined intervention—CBT and a serious game—showed positive results in terms of treatment outcomes.

Effects of Rhythmic Auditory Stimulation on Gait and Motor Function in Parkinson's Disease: A Systematic Review and Meta-Analysis of Clinical Randomized Controlled Studies

Objective

This study aimed to summarize the effectiveness of rhythmic auditory stimulation (RAS) for the treatment of gait and motor function in Parkinson's disease (PD) through a systematic review and meta-analysis.

Methods

All studies were retrieved from eight databases. The effects of RAS on PD were determined using the following indicators: gait parameters including step length, stride width, step cadence, velocity, stride length; motor function including 6 min walk test (6MWT) and timed up-and-go test (TUGT); the Unified Parkinson's Disease Rating Scale (UPDRS); and the Berg Balance Scale (BBS). The risk map of bias of the quality of the studies and the meta-analysis results of the indicators was prepared with RevMan 5.2 software.

Results

Twenty-one studies were included in the systematic review, and 14 studies were included in the meta-analysis. In the meta-analysis, the results of gait parameters, namely, velocity, step length, and stride length, were statistically significant (P < 0.05), whereas the results of cadence and stride width were not statistically significant (P ≧ 0.05). The results of 6MWT and TUGT for motor function as well as UPDRS-II, UPDRS-III, and BBS were statistically significant (P < 0.05).

Conclusions

RAS could improve gait parameters, walking function, balance function, and daily living activities of individuals with PD. The application of RAS in conventional rehabilitation approaches can enhance motor performance in PD. Future studies should use a large sample size and a rigorous design to obtain strong conclusions about the advantages of RAS for the treatment of gait and motor function in PD.

Prevalence, clinical presentations and impact on relationship of sexual dysfunction in Parkinson's Disease

Sexual dysfunction is one of the commonest non-motor symptoms in Parkinson's disease (PD) and has been found about twice as high in PD patients compared to age-matched controls. The quality of sexual life is reduced in PD patients compared to healthy peers and impairment affects wide aspects of physical sexual function as well as sexual desire, sexual satisfaction and sexual partnership. Overall, male PD patients are more frequently affected by sexual disorders than females and seem to suffer more from sexual impairment. The reported frequencies and presentations of various sexual dysfunctions vary widely in the literature, which is likely related to the patient cohorts examined, in particular with regard to age and gender, duration and severity of disease and applied measurement instruments. This chapter gives an overview of the prevalence, phenotype and clinical presentation of sexual dysfunction in PD and its influence on the partnership.

Trait Anxiety as a Risk Factor for Impulse Control Disorders in de novo Parkinson's Disease

BACKGROUND

In addition to the well-known motor symptoms, patients with Parkinson's disease (PD) also frequently experience disabling non-motor symptoms including impulse control disorders (ICDs). ICDs are characterized by a loss of voluntary control over impulses, drives, or temptations regarding excessive hedonic behavior.

OBJECTIVE

The present study examined whether depression and anxiety in de novo PD patients predict the prospective development of ICDs.

METHODS

We selected 330 de novo PD patients from the Parkinson's Progression Markers Initiative database who were free of ICDs at the start of the study. ICD presence at baseline and follow-up assessments was evaluated via the shortened version of the Questionnaire for Impulsive-Compulsive Disorders (QUIP-S). Baseline depression and anxiety were measured via the Geriatric Depression Scale (GDS-15) and State-Trait-Anxiety Inventory (STAI-Y), respectively.

RESULTS

A total of 149 participants (45.2%) developed an ICD at follow-up and average time of ICD onset was 35 months after baseline. Results of a Cox regression analysis showed that STAI-Y scores but not GDS-15 scores significantly predicted ICD presence. Specifically, scores reflecting higher trait anxiety were associated with an increased risk of developing an ICD. This effect was not confounded by age, gender or UPDRS motor score. We also replicated the well-established result that dopamine agonist use is predictive of ICDs.

CONCLUSION

Our findings indicate that higher anxiety levels in de novo PD patients represent a risk factor for ICD development during the course of the disorder. This highlights the need for early and routine based anxiety screening in these patients.

Dopamine-induced changes to thalamic GABA concentration in impulsive Parkinson disease patients

Impulsivity is inherent to behavioral disorders such as substance abuse and binge eating. While the role of dopamine in impulse behavior is well established, γ-aminobutyric acid (GABA) therapies have promise for the treatment of maladaptive behaviors. In Parkinson disease (PD), dopaminergic therapies can result in the development of impulsive and compulsive behaviors, and this clinical syndrome shares similar pathophysiology to that seen in addiction, substance abuse, and binge-eating disorders. We hypothesized that impulsive PD patients have a reduced thalamic GABAergic response to dopamine therapy. To test this hypothesis, we employed GABA magnetic resonance spectroscopy, D2-like receptor PET imaging, and clinical and quantitative measures of impulsivity in PD patients (n = 33), before and after dopamine agonist administration. We find a blunted thalamic GABA response to dopamine agonists in patients with elevated impulsivity (p = 0.027). These results emphasize how dopamine treatment differentially augments thalamic GABA concentrations, which may modify behavioral impulsivity.

Pingchan Granule for Motor Symptoms and Non-Motor Symptoms of Parkinson’s Disease: A Randomized, Double-Blind, Placebo-Controlled Study

Background: Pingchan granule (PCG) is a traditional Chinese medicine for treating Parkinson’s disease (PD).

Objective: This study aimed at evaluating the efficacy and safety of PCG for motor and non-motor symptoms of PD.

Methods: In this multicenter, randomized, double-blind, placebo-controlled trial, 292 participants with mild-to-moderate PD were included and followed for 36 weeks (24 week treatment, 12-week follow-up after intervention), randomly assigned at a 1:1 ratio to receive PCG or placebo. The primary outcomes included the severity of motor symptoms assessed by the Unified Parkinson’s disease Rating Scale (UPDRS) part 3 (UPDRS-III) score and the rate of disease progression assessed by the total UPDRS score. Secondary outcomes included non-motor symptoms assessed using the Scale for Outcomes in Parkinson’s Disease-Autonomic (SCOPA-AUT), Parkinson’s disease Sleep Scale (PDSS), 24-item Hamilton Rating Scale for Depression (HAM-D), Hamilton Rating Scale for Anxiety (HAM-A), UPDRS part 2 (UPDRS-II), and 39-item Parkinson’s Disease Questionnaire (PDQ-39) scores. Assessments were done at baseline (T0), 12 weeks (T1), 24 weeks (T2), and 36 weeks (T3).

Results: Generalized estimating equation analyses revealed that the PCG group had significantly better improvement in UPDRS-III score at T1, T2, and T3 [time-by-group interaction, T1: β, −0.92 (95% CI, −1.59–−0.25; p = 0.01); T2: β, −2.08 (95% CI, −2.90–−1.27; p < 0.001); T3: β, −4.54 (95% CI, −5.37–−3.71; p < 0.001))]. The PCG group showed a greater decrease (rate of disease change) in the total UPDRS score between T0 and T2 [−2.23 (95% CI, −2.72–−1.73; p < 0.001) points per week vs. −0.21 (95% CI, −0.80–0.39; p = 0.50) points per week in the placebo group, p < 0.001]. Ameliorations of SCOPA-AUT, PDSS, HAM-D, HAM-A, UPDRS-II, and PDQ-39 scores were also observed.

Conclusion: PCG had a long-lasting and extensive symptomatic efficacy for both motor and non-motor symptoms of PD with good tolerance.

Trial registration: Chinese Clinical Trial Register, ChiCTR-INR-17011949.

Functional correlates of response inhibition in impulse control disorders in Parkinson's disease

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PD patients with ICD behave like controls in proactive and reactive inhibition.

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PD patients with ICD recruit different mechanisms depending on the inhibition type.

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Proactive inhibition is executed hyperactivating the stopping network bilaterally.

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Restrained inhibition is accomplished with the coactivation of attentional areas.

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In restrained inhibition, connectivity between right STN and precuneus is reduced.

Impulse control disorder is a prevalent side-effect of Parkinson’s disease (PD) medication, with a strong negative impact on the quality of life of those affected. Although impulsivity has classically been associated with response inhibition deficits, previous evidence from PD patients with impulse control disorder (ICD) has not revealed behavioral dysfunction in response inhibition. In this study, 18 PD patients with ICD, 17 PD patients without this complication, and 15 healthy controls performed a version of the conditional Stop Signal Task during functional magnetic resonance imaging. Whole-brain contrasts, regions of interest, and functional connectivity analyses were conducted. Our aim was to investigate the neural underpinnings of two aspects of response inhibition: proactive inhibition, inhibition that has been prepared beforehand, and restrained inhibition, inhibition of an invalid inhibitory tendency. We observed that, in respect to the other two groups, PD patients with ICD exhibited hyperactivation of the stopping network bilaterally while performing proactive inhibition. When engaged in restrained inhibition, they showed hyperactivation of the left inferior frontal gyrus, an area linked to action monitoring. Restrained inhibition also resulted in changes to the functional co-activation between inhibitory regions and left inferior parietal cortex and right supramarginal gyrus. Our findings indicate that PD patients with ICD completed the inhibition task correctly, showing altered engagement of inhibitory and attentional areas. During proactive inhibition they showed bilateral hyperactivation of two inhibitory regions, while during restrained inhibition they showed additional involvement of attentional areas responsible for alerting and orienting.

Bipolar spectrum disorders in neurologic disorders

Psychiatric symptoms frequently predate or complicate neurological disorders, such as neurodegenerative diseases. Symptoms of bipolar spectrum disorders (BSD), like mood, behavioral, and psychotic alterations, are known to occur - individually or as a syndromic cluster - in Parkinson's disease and in the behavioral variant of frontotemporal dementia (FTD). Nonetheless, due to shared pathophysiological mechanisms, or genetic predisposition, several other neurological disorders show significant, yet neglected, clinical and biological overlaps with BSD like neuroinflammation, ion channel dysfunctions, neurotransmission imbalance, or neurodegeneration. BSD pathophysiology is still largely unclear, but large-scale network dysfunctions are known to participate in the onset of mood disorders and psychotic symptoms. Thus, functional alterations can unleash BSD symptoms years before the evidence of an organic disease of the central nervous system. The aim of our narrative review was to illustrate the numerous intersections between BSD and neurological disorders from a clinical-biological point of view and the underlying predisposing factors, to guide future diagnostic and therapeutical research in the field.

Autophagy-Lysosomal Pathway as Potential Therapeutic Target in Parkinson's Disease

Cellular quality control systems have gained much attention in recent decades. Among these, autophagy is a natural self-preservation mechanism that continuously eliminates toxic cellular components and acts as an anti-ageing process. It is vital for cell survival and to preserve homeostasis. Several cell-type-dependent canonical or non-canonical autophagy pathways have been reported showing varying degrees of selectivity with regard to the substrates targeted. Here, we provide an updated review of the autophagy machinery and discuss the role of various forms of autophagy in neurodegenerative diseases, with a particular focus on Parkinson's disease. We describe recent findings that have led to the proposal of therapeutic strategies targeting autophagy to alter the course of Parkinson's disease progression.

Optimal testosterone level to improve symptoms of hypogonadism without causing dopa-testotoxicosis in male macroprolactinoma

BACKGROUND

Male prolactinoma treatment by dopamine agonists (DA) restores sexual function. However, excessive DA dose can lead to impulse control disorder.

OBJECTIVES

The aim of this retrospective study was to determine the level of testosterone that eliminates symptoms and provides fertility in male macroprolactinoma, without causing these adverse effects.

MATERIALS AND METHODS

Twenty-seven male patients with macroprolactinoma were included. There were 16 macro (≥1-2.8 cm), 7 large macro (≥2.9-3.9 cm) and 4 giant (≥4 cm) adenomas. Prolactin (PRL) and testosterone (T) levels were evaluated. A timeline was created to analyze improvement in symptoms of hypogonadism and infertility. Testosterone levels were compared with age-matched controls.

RESULTS

Mean PRL, basal tumor diameter and shrinkage were 2,846±3,415 ng/mL, 27.2±10.2 mm and 63.4%, respectively. Basal T levels were 1.6±1.0 ng/mL for patients and 4.4±1.5 ng/mL for controls (p<0.001). Mean T level in the asymptomatic period was significantly lower than in controls (3.2±0.4 ng/mL vs. 4.4±1.5 ng/mL, respectively; p=0.002), while mean PRL was 27.2 ng/ml. Fertility was achieved in 6 of the patients seeking fertility, and there was no difference in T level between these patients and controls (3.7±0.8 ng/mL and 4.4±1.5 ng/mL, respectively; p=0.14); when fertility was achieved, mean PRL was 26.9±23 ng/mL.

CONCLUSION

Patients should be carefully questioned regarding complaints at each consultation, and DA dose should not be increased unnecessarily, to avoid possible serious adverse effects.

Predictors of short-term impulsive and compulsive behaviour after subthalamic stimulation in Parkinson disease

BACKGROUND

The effects of subthalamic stimulation (subthalamic nucleus-deep brain stimulation, STN-DBS) on impulsive and compulsive behaviours (ICB) in Parkinson's disease (PD) are understudied.

OBJECTIVE

To investigate clinical predictors of STN-DBS effects on ICB.

METHODS

In this prospective, open-label, multicentre study in patients with PD undergoing bilateral STN-DBS, we assessed patients preoperatively and at 6-month follow-up postoperatively. Clinical scales included the Questionnaire for Impulsive-Compulsive Disorders in PD-Rating Scale (QUIP-RS), PD Questionnaire-8, Non-Motor Symptom Scale (NMSS), Unified PD Rating Scale in addition to levodopa-equivalent daily dose total (LEDD-total) and dopamine agonists (LEDD-DA). Changes at follow-up were analysed with Wilcoxon signed-rank test and corrected for multiple comparisons (Bonferroni method). We explored predictors of QUIP-RS changes using correlations and linear regressions. Finally, we dichotomised patients into 'QUIP-RS improvement or worsening' and analysed between-group differences.

RESULTS

We included 55 patients aged 61.7 years±8.4 with 9.8 years±4.6 PD duration. QUIP-RS cut-offs and psychiatric assessments identified patients with preoperative ICB. In patients with ICB, QUIP-RS improved significantly. However, we observed considerable interindividual variability of clinically relevant QUIP-RS outcomes as 27.3% experienced worsening and 29.1% an improvement. In post hoc analyses, higher baseline QUIP-RS and lower baseline LEDD-DA were associated with greater QUIP-RS improvements. Additionally, the 'QUIP-RS worsening' group had more severe baseline impairment in the NMSS attention/memory domain.

CONCLUSIONS

Our results show favourable ICB outcomes in patients with higher preoperative ICB severity and lower preoperative DA doses, and worse outcomes in patients with more severe baseline attention/memory deficits. These findings emphasise the need for comprehensive non-motor and motor symptoms assessments in patients undergoing STN-DBS.

TRIAL REGISTRATION NUMBER

DRKS00006735.

The prevalence of impulsive compulsive behaviors in patients treated with apomorphine infusion: a retrospective analysis

BACKGROUND

Impulsive compulsive behaviors (ICBs) can affect a significant number of Parkinson's disease (PD) patients.

OBJECTIVE

We have studied brain samples from a brain bank of PD patients who received apomorphine via continuous infusion in life to assess the prevalence and outcome of ICBs.

METHODS

A search on the Queen Square Brain Bank (QSBB) database for cases donated from 2005 to 2016 with a pathological diagnosis of idiopathic PD was conducted. Notes of all donors who used apomorphine via continuous infusion for at least three months were reviewed. Clinical and demographic data were collected, as well as detailed information on treatment, prevalence and outcomes of ICBs.

RESULTS

193 PD cases, 124 males and 69 females, with an average age at disease onset of 60.2 years and average disease duration of 17.2 years were reviewed. Dementia occurred in nearly half of the sample, depression in one quarter, and dyskinesias in a little over 40%. The prevalence of ICBs was 14.5%. Twenty-four individuals used apomorphine infusion for more than three months. Patients on apomorphine had younger age at disease onset, longer disease duration, and higher prevalence of dyskinesias. The prevalence of de novo ICB cases among patients on apomorphine was 8.3%. Apomorphine infusion was used for an average of 63.1 months on an average maximum dose of 79.5 mg per day. Ten patients remained on apomorphine until death.

CONCLUSIONS

Apomorphine can be used as an alternative treatment for patients with previous ICBs as it has low risk of triggering recurrence of ICBs.

Cognitive and Behavior Deficits in Parkinson's Disease with Alteration of FDG-PET Irrespective of Age

Significant progress has been made in our understanding of the neurobiology of Parkinson’s disease (PD). Post-mortem studies are an important step and could help to comprehend not only the progression of motor symptoms, but also the involvement of other clinical domains, including cognition, behavior and impulse control disorders (ICDs). The correlation of neuropathological extension of the disease with the clinical stages remains challenging. Molecular imaging, including positron emission tomography (PET) and single photon computed tomography (SPECT), could allow for bridging the gap by providing in vivo evidence of disease extension. In the last decade, we have observed a plethora of reports describing improvements in the sensitivity of neuroimaging techniques. These data contribute to increasing the accuracy of PD diagnosis, differentiating PD from other causes of parkinsonism and also obtaining a surrogate marker of disease progression. FDG-PET has been used to measure cerebral metabolic rates of glucose, a proxy for neuronal activity, in PD. Many studies have shown that this technique could be used in early PD, where reduced metabolic activity correlates with disease progression and could predict histopathological diagnosis. The aim of this work is to report two particular cases of PD in which the assessment of brain metabolic activity (from FDG-PET) has been combined with clinical aspects of non-motor symptoms. Integration of information on neuropsychological and metabolic imaging allows us to improve the treatment of PD patients irrespective of age.

Amantadine Revisited: A Contender for Initial Treatment in Parkinson's Disease?

The best practice for the initiation of symptomatic motor treatment for Parkinson's disease is an ongoing topic of debate. Fueled by interpretation of the results of the LEAP and MED Parkinson's disease studies, many practitioners opt for early initiation of levodopa formulations, avoiding dopamine agonists to circumvent potential deleterious side effects, namely impulse control disorder. Compared with levodopa, monoamine oxidase inhibitors may lack necessary potency. Ignored in this academic debate is another therapeutic option for patients with Parkinson's disease requiring treatment initiation: amantadine. Amantadine was first reported effective in the treatment of Parkinson's disease in 1969 and several studies were published in the 1970s supporting its efficacy. Currently, amantadine is mainly utilized as an add-on therapy to mitigate levodopa-related dyskinesia and, more recently, new long-acting amantadine formulations have been developed, with new indications to treat motor fluctuations. Amantadine has not been reported to cause dyskinesia and is rarely implicated in impulse control disorder.

Analysis of Impulse Control Disorders (ICDs) and Factors Associated with Their Development in a Parkinson's Disease Population

Parkinson's Disease (PD) is a neurodegenerative disease in which non-motor symptoms may appear before motor phenomena, which include Impulse Control Disorders (ICDs). The objective of this study is to identify factors associated with the development of ICDs in PD. An analytical, cross-sectional study was conducted using clinical records from patients diagnosed with PD, both genders, from 40 to 80 years old. Clinical and demographic data were collected: 181 patients were recruited; 80 of them showed PD and ICDs, and they constituted the study group, whereas 101 patients with PD without ICDs constituted the control reference group. The duration of PD was longer in the group with ICDs (p < 0.008), and all patients showed at least one ICD: binge eating (61.29%), compulsive shopping (48.75%), hypersexuality (23.75%), gambling behavior (8.75%), and punding (3.75%). After logistic regression analysis, only the use of dopamine agonists remained associated with ICDs (p < 0.001), and the tremorgenic form was suggested to be a protective factor (p < 0.001). Positive associations were observed between the rigid-akinetic form and compulsive shopping (p < 0.007), between male and hypersexuality (p < 0.018), and between dopamine agonists and compulsive shopping (p < 0.004), and negative associations were observed between motor fluctuations and compulsive shopping (p < 0.031), between Deep Brain Stimulation and binge eating (p < 0.046), and between levodopa consumption and binge eating (p < 0.045). Binge eating, compulsive shopping, and hypersexuality were the most frequent ICDs. Complex forms and motor complications of PD were associated with the development of ICDs.

Risk factors of impulsive-compulsive behaviors in PD patients: a meta-analysis

OBJECTIVE

To summarize the reliable risk factors of impulsive-compulsive behaviors (ICBs) in Parkinson's disease (PD) patients through a meta-analysis on studies in which PD-ICBs were diagnosed by clinical interview.

METHODS

PubMed, Embase, Web of Science, CNKI and Wanfang databases were searched. We selected studies ensuring that diagnosis of ICBs in PD patients depends on semi-structured interviews according to the clinical diagnostic criteria of ICBs. The Newcastle-Ottawa Scale was used to evaluate quality of the included studies. The analyzed factors included demographic information, clinical characteristics of PD and medications.

RESULTS

A total of 856 records were screened and 66 full texts were evaluated, and 13 studies (684 PD patients with ICBs [PD-ICBs] and 3,382 PD patients without ICBs [PD-non-ICBs]) were included. Compared with PD-non-ICBs, PD-ICBs were younger in age (- 3.7 [- 5.53, - 1.87], P < 0.0001), with a greater proportion of males (1.64 [1.21, 2.22], P = 0.001), with a younger age of PD onset (- 5.42 [- 7.87, - 2.97], P < 0.0001) and a longer course of PD (1.30 [0.38, 2.22], P = 0.005). PD-ICBs were also associated with higher HAM-D (1.74 [0.47, 3.01], P = 0.007), more levodopa dosage (1.74 [1.09, 2.77], P = 0.02) and dopamine receptor agonists (DA) use (3.96 [2.74, 5.71), P < 0.00001), and higher average dose (levodopa 117.53 [53.59, 181.46], P = 0.0003; DA 80.03 [46.16, 113.90], P < 0.00001), as well as more amantadine use (2.20 [1.42, 3.40], P = 0.0004). The meta-analysis of most factors showed less heterogeneity, except age, age of onset, PD duration, Hoehn and Yahr stage, MMSE and drug dosage. However, whether rapid eye movement sleep behavior disorder, dyskinesia, genetic polymorphism and other factors are risk factors for PD-ICBs remains unclear.

CONCLUSION

This meta-analysis suggests that males, young, early disease onset, long disease duration, depression, dose of levodopa, dopamine receptor agonists and amantadine are risk factors of ICBs in PD patients.

Neuropeptide S Receptor as an Innovative Therapeutic Target for Parkinson Disease

Parkinson disease (PD) is a neurodegenerative disease mainly characterized by the loss of nigral dopaminergic neurons in the substantia nigra pars compacta. Patients suffering from PD develop severe motor dysfunctions and a myriad of non-motor symptoms. The treatment mainly consists of increasing central dopaminergic neurotransmission and alleviating motor symptoms, thus promoting severe side effects without modifying the disease’s progress. A growing body of evidence suggests a close relationship between neuropeptide S (NPS) and its receptor (NPSR) system in PD: (i) double immunofluorescence labeling studies showed that NPSR is expressed in the nigral tyrosine hydroxylase (TH)-positive neurons; (ii) central administration of NPS increases spontaneous locomotion in naïve rodents; (iii) central administration of NPS ameliorates motor and nonmotor dysfunctions in animal models of PD; (iv) microdialysis studies showed that NPS stimulates dopamine release in naïve and parkinsonian rodents; (v) central injection of NPS decreases oxidative damage to proteins and lipids in the rodent brain; and, (vi) 7 days of central administration of NPS protects from the progressive loss of nigral TH-positive cells in parkinsonian rats. Taken together, the NPS/NPSR system seems to be an emerging therapeutic strategy for alleviating motor and non-motor dysfunctions of PD and, possibly, for slowing disease progress.

Prevalence of malnutrition/malnutrition risk and nutrition-related risk factors among patients with Parkinson's disease: systematic review and meta-analysis

INTRODUCTION

The clinical symptoms and nutritional status of patients with Parkinson's disease (PwP) are interrelated, and the clinical outcomes in malnourished patients are often poor. Only a few studies have reviewed the prevalence of malnutrition and nutrition-related risk factors in PwP.

OBJECTIVE

To explore the prevalence of malnutrition/ malnutrition risk among PwP, and estimate nutrition-related risk factors.

METHODS

PubMed, EMBASE, and Cochrane Library were systematically searched. Literatures published between 1 January 1995 and 1 November 2020, subjects were patients with idiopathic PD underwent Mini Nutritional Assessment (MNA) were included.

RESULT

Sixteen articles, including 1650 PwP from 13 countries/regions, were included in the meta-analysis. The prevalence of malnutrition and malnutrition risk were 8.8% (Confidence interval [CI] 95%, 5.3%-12.2%) and 35.3% (CI 95%, 29.0%-41.7%), and the prevalence of nutritional disorders was 42.3% (CI 95%, 33.7%-51%). The prevalence of malnutrition in developing countries was higher than that in the developed countries. Meta-analysis reveals there were significant differences in the course of the disease (0.88 years; 95% CI, 0.26-1.50), levodopa equivalent daily dose (LEDD; 60.77 mg/day; 95% CI, 2.7-118.8), Hoehn and Yahr (H&Y) staging (0.323; CI 95%, 0.164-0.482), and unified Parkinson's disease rating scale (UPDRS) scores (total: 13.66, CI 95%: 10.57-16.75 and part III: 5.52, CI 95%: 3.79-7.25) between normal and nutritional disorder groups.

CONCLUSIONS

Malnutrition/malnutrition risk prevalence in PwP are high. The duration of the disease, LEDD, H&Y staging, and UPDRS score (part III and total) may be nutrition-related risk factors in PwP.

FGF, Mechanism of Action, Role in Parkinson's Disease, and Therapeutics

Parkinson’s disease (PD) is a neurodegenerative disease associated with severe disability and adverse effects on life quality. In PD, motor dysfunction can occur, such as quiescence, muscle stiffness, and postural instability. PD is also associated with autonomic nervous dysfunction, sleep disorders, psychiatric symptoms, and other non-motor symptoms. Degeneration of dopaminergic neurons in the substantia nigra compact (SNPC), Lewy body, and neuroinflammation are the main pathological features of PD. The death or dysfunction of dopaminergic neurons in the dense part of the substantia nigra leads to dopamine deficiency in the basal ganglia and motor dysfunction. The formation of the Lewy body is associated with the misfolding of α-synuclein, which becomes insoluble and abnormally aggregated. Astrocytes and microglia mainly cause neuroinflammation, and the activation of a variety of pro-inflammatory transcription factors and regulatory proteins leads to the degeneration of dopaminergic neurons. At present, PD is mainly treated with drugs that increase dopamine concentration or directly stimulate dopamine receptors. Fibroblast growth factor (FGF) is a family of cellular signaling proteins strongly associated with neurodegenerative diseases such as PD. FGF and its receptor (FGFR) play an essential role in the development and maintenance of the nervous system as well as in neuroinflammation and have been shown to improve the survival rate of dopaminergic neurons. This paper summarized the mechanism of FGF and its receptors in the pathological process of PD and related signaling pathways, involving the development and protection of dopaminergic neurons in SNPC, α-synuclein aggregation, mitochondrial dysfunction, and neuroinflammation. It provides a reference for developing drugs to slow down or prevent the potential of PD.

Bilirubin: A Promising Therapy for Parkinson's Disease

Following the increase in life expectancy, the prevalence of Parkinson's disease (PD) as the most common movement disorder is expected to rise. Despite the incredibly huge efforts in research to find the definitive biomarker, to date, the diagnosis of PD still relies mainly upon clinical symptoms. A wide range of treatments is available for PD, mainly alleviating the clinical symptoms. However, none of these current therapies can stop or even slow down the disease evolution. Hence, disease-modifying treatment is still a paramount unmet medical need. On the other side, bilirubin and its enzymatic machinery and precursors have offered potential benefits by targeting multiple mechanisms in chronic diseases, including PD. Nevertheless, only limited discussions are available in the context of neurological conditions, particularly in PD. Therefore, in this review, we profoundly discuss this topic to understand bilirubin's therapeutical potential in PD.

Increased risk for developing gambling disorder under the treatment with pramipexole, ropinirole, and aripiprazole: A nationwide register study in Sweden

Gambling Disorder (GD) has recently been reclassified from an impulse-control disorder to a behavioural addiction and, as in other addictive disorders, the dopaminergic reward system is involved. According to neuroimaging studies, alterations within the striatal dopaminergic signalling can occur in GD. However, the findings to date are controversial and there has been no agreement yet on how the reward system is affected on a molecular basis. Within the last 20 years, there has been growing evidence for a higher risk to develop GD in response to certain dopaminergic medication. Especially the dopamine agonists pramipexole and ropinirole, and the dopamine modulator aripiprazole seem to increase the likelihood for GD. The goal of this study was to examine the association between a prescription for either of the three pharmaceuticals and a GD diagnosis in a large cross-sectional study of the Swedish population. Compared to patients with any other dopaminergic drug prescription (38.7% with GD), the diagnosis was more common in patients with a dopamine agonist prescription (69.8% with GD), resulting in an odds ratio of 3.2. A similar association was found between aripiprazole prescriptions and GD diagnoses, which were analysed within the subgroup of all patients with schizophrenia or a schizotypal, delusional, or another non-mood psychotic disorder. An aripiprazole prescription increased the likelihood of GD (88.8%) in comparison to patients without an aripiprazole prescription (71.2%) with an odds ratio of 3.4. This study contributes to the increasingly reliable evidence for an association between several dopaminergic drugs and a higher risk for developing GD. Therefore, one future research goal should be a better understanding of the neurobiology in GD to be able to design more selective dopaminergic medication with less severe side effects. Additionally, this knowledge could enable the development of pharmacotherapy in GD and other addictive disorders.