Research Article: Impulse control disorders in Parkinson’s disease: A systematic review on the psychometric properties of the existing measures

Date Published: June 4, 2019

Publisher: Public Library of Science

Author(s): Viola Angela Izzo, Maria Anna Donati, Silvia Ramat, Caterina Primi, John Duda.


A significant percentage of patients suffering from Parkinson’s Disease (PD) experience Impulse Control Disorders (ICDs), contributing to reduced quality of life. As they can be managed by reducing the dopamine dosage, the detection of their presence is crucial for PD treatment plan. Nevertheless, they tend to be under-recognized in clinical practice, since routine screening is not common–despite existing instruments that may support clinicians. This work presents a systematic review on the psychometric properties of instruments measuring ICDs in PD, to test whether clinicians dispose of valid tools that may help them in clinical assessment.

A systematic literature search in three databases (EMBASE, MEDLINE, and PsycINFO) was conducted. Quality of the instruments’ psychometric properties was evaluated with Terwee et al.’s criteria, and methodological quality of the studies was evaluated with the COSMIN Checklist.

Ten studies examining seven instruments were selected. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s Disease (QUIP) and the Ardouin Scale of Behavior in Parkinson’s Disease (ASBPD) resulted to be the best from a psychometric point of view.

Though the gold standard for diagnosis remains a detailed diagnostic interview, this review will encourage clinicians to use validated tools to accurately assess ICDs.

Partial Text

Parkinson’s disease (PD) represents the second most common neurodegenerative disorder after Alzheimer’s disease, with a prevalence of 1–2% in those over the age of sixty and 3–5% in those over 85 years old [1, 2]. Symptoms mainly involve movement, so that PD’s most well-known signs are tremor, bradykinesia, muscle stiffness and impaired balance and coordination. Nonetheless, there is well-established evidence that cognition and emotion are also impaired, with psychiatric symptoms being present in more than 60% of PD patients [3]. Among the non-motor symptoms, concern has arisen for a peculiar group of impulsive behaviors, known as Impulse Control Disorders (ICDs), which occur in up to 20% of PD patients [4]. ICDs are a group of behaviors characterized by a failure to resist an impulse, drive, or temptation to perform an act that is harmful to oneself or to others [5]. They include pathological gambling [6], hypersexuality [7], compulsive eating [8], and compulsive buying [9]. Along with them, other related impulsive-compulsive behaviors occur, including punding [10], hobbyism [11], walkabouts [12], and a peculiar condition named Dopamine Dysregulation Syndrome (DDS), defined as a compulsive use of dopamine medications despite adequate motor benefits and the annoying consequences [13].

Methods of this systematic review were specified before starting the study according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines [41]. The methods are specified as follows.

The search returned 1913 publications. After excluding 1257 duplicates, we reviewed the titles and abstracts for each of the 656 remaining publications. Among them, 321 studies met the inclusion criteria of being peer-reviewed full-text articles published in English that examined ICDs in PD patients. However, of those 321 articles, 311 were removed as they administered tools assessing ICDs in PD patients, but did not examine their psychometric properties. As a final result, ten studies were identified (Fig 1).

Impulse Control Disorders are one of the most frequent non-motor features of PD, occurring in up to 20% of PD patients [4]. ICDs worsen quality of life and are responsible for several emotional and social impairments [33, 35, 46]. Though not being the only responsible factor for the onset of ICDs, dopaminergic treatment, mainly dopamine agonists, plays an important role [4, 27]. In fact, case reports suggested that ICDs often resolve after adjusting the therapeutic dosage [38, 39]. Thus, to better address patients’ needs and delineate a specific intervention that may include treatment modifications, an accurate assessment of the presence of ICDs is recommended.