Clinical and psychopathological factors associated with impulse control disorders in Parkinson's disease

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.

Impulse control disorders, dopamine dysregulation syndrome and sex dysfunction in Parkinson's disease

Hypersexuality (HS), characterized by an aberrant, compulsive and inappropriate sexual drive, is an underreported and undermanaged complication of the treatment with dopamine agonists in patients with Parkinson's disease (PD). HS is part of the spectrum of impulse control disorders (ICDs). The failure to control these addictive behaviors is distressing for the patient and it is associated with important consequences. Reports of the prevalence of HS showed different results, due to the lack of standardized diagnostic criteria, but also due to the embarrassment or guilt feelings that patients experience regarding their sexual behaviors. Overall, it is considered that HS may occur in 1.92-22.8% of PD patients and the main risk factors involved could be male sex and genetic susceptibility. The pathophysiology of HS is unknown, but several degenerative mechanisms were proposed, involving dopaminergic, serotoninergic and noradrenergic pathways in cerebral regions responsive for planning and rewarding. There are no standardized tools for the assessment of HS in PD patients; however, several scales and questionnaires were developed with the aim of screening and rating the severity of ICDs, including HS. The management of HS is challenging. Discontinuation or reducing the dopaminergic treatment was effective in some cases, but it might lead to worsening of the motor function. A multidisciplinary approach is mandatory to manage the other associated aspects, such as psychological and social consequences of HS.

Impact of behavioral side effects on the management of Parkinson patients treated with dopamine agonists

Dopamine agonists are one of the main stay of treatment option for Parkinson disease (PD). Side effects that develop from their use are generally categorized into behavioral and non-behavioral. Behavioral side effects include: impulse control behavior disorder (ICD), psychosis and cognitive impairment. Non-behavioral side effects include: nausea/vomiting, "sleep attacks", leg swelling, weight gain and orthostasis. The aim of this study is to evaluate the clinicians' response to PD patients who developed behavioral side effects from dopamine agonists, in comparison to those patients who developed only non-behavioral side effects. We performed a retrospective chart review of all patients diagnosed with PD over a two year period. Among 313 patients who were on a dopamine agonist, 156 reported side effects. Sixty-five patients reported behavioral (with or without non-behavioral) side effects, while 91 experienced only non-behavioral side effects. Forty-nine out of the 65 patients (75.3%) who experienced behavioral side effects had their dopamine agonist dose decreased compared to 53 out of 91patients (58.2%) who experienced only non-behavioral side effects (Chi square = 4.92, p < 0.05). Patients with behavioral side effects were 3 times more likely have their dose decreased (OR = 3.3; 95%CI = 1.442-7.551; P = 0.005). However, neither taper speed nor the occurrence of dopamine agonist withdrawal syndrome (DAWS) differed between the two groups. Amongst PD patients treated with dopamine agonists, the presence of behavioral side effects independently increased the chance of dopamine agonist dose reduction. Prospective studies are needed to confirm these findings.

Impulse Control Disorders in Parkinson's Disease: Epidemiology, Pathogenesis and Therapeutic Strategies

Impulse control disorders (ICDs) in Parkinson's disease (PD) are aberrant behavior such as pathological gambling, hypersexuality, binge eating, and compulsive buying, which typically occur as a result of dopaminergic therapy. Numerous studies have focused on the broad spectrum of ICDs-related behaviors and their tremendous impact on patients and their family members. Recent advances have improved our understanding of ICDs. In this review, we discuss the epidemiology, pathogenesis and treatment of ICDs in the setting of PD.

Dopamine Agonists and Impulse Control Disorders: A Complex Association

Impulse control disorders (ICDs) are a well-known adverse effect of dopamine agonists (DAAs). This critical review aims to summarize data on the prevalence and factors associated with the development of an ICD simultaneous to DAA use. A search of two electronic databases was completed from inception to July 2017. The search terms were medical subject headings (MeSH) terms including “dopamine agonists” AND “disruptive disorders”, “impulse control disorders”, or “conduct disorders”. Articles had to fulfill the following criteria to be included: (i) the target problem was an ICD; (ii) the medication was a dopaminergic drug; and (iii) the article was an original article. Of the potential 584 articles, 90 met the criteria for inclusion. DAAs were used in Parkinson’s disease (PD), restless legs syndrome (RLS) or prolactinoma. The prevalence of ICDs ranged from 2.6 to 34.8% in PD patients, reaching higher rates in specific PD populations; a lower prevalence was found in RLS patients. We found only two studies about prolactinoma. The most robust findings relative to the factors associated with the development of an ICD included the type of DAA, the dosage, male gender, a younger age, a history of psychiatric symptoms, an earlier onset of disease, a longer disease duration, and motor complications in PD. This review suggests that DAA use is associated with an increased risk in the occurrence of an ICD, under the combined influence of various factors. Guidelines to help prevent and to treat ICDs when required do exist, although further studies are required to better identify patients with a predisposition.