Impulse control disorders (ICDs) are an adverse effect of dopamine agonists (DAAs) that affects the quality of life and can lead to legal, criminal and familiar problems.

Presenting a review of the mechanisms, prevalence and factors associated with the development of an ICD due to DAA use.

Search on Pubmed database with combination of the following keywords were used: “Impulse control disorders”, “dopamine agonist” or “therapy”. We focused on data from studies published between 2015 and 2020. The articles were selected by the author according to their relevance.

DAAs are mainly indicated in the treatment of Parkinson’s Disease (PD), and are also used on symptoms of restless legs syndrome (RLS) and prolactinoma or lactation inhibition. Dopamine replacement therapy act on dopamine receptors in the nigrostriatal and the reward pathways, which plays a role in addictive behavior. The prevalence of ICDs ranged from 2.6 to 34.8% in PD patients and a lower prevalence in RLS patients. Some of the ICDs reported were pathological gambling, hypersexuality, compulsive shopping, obsessive hobbying, punding, and compulsive medication use. The factors associated with the development include the type of DAAs, dosage, male gender, younger age, history of psychiatric symptoms, earlier onset of disease, longer disease duration, and motor complications in PD.

Further studies are needed to clarify the pathophysiology of the ICD in DAA therapy and determinate premorbid risk factors. The percentage of patients with ICDs is underrated, so it’s important to improve the patient’s evaluation, using validated and consensual assessment tools.

In the past decade, neurobiological research on pathological gambling has flourished. Based on neurobiological similarities between pathological gambling and substance use disorders and similarities in genetics, diagnostic criteria, and effective treatments, pathological gambling was the first behavioral addiction to be included in the DSM-5 within the revised category Substance-related and addictive disorders.

In this presentation novel findings from gambling research in our research group focusing on the role of impulsivity, anticipation towards monetary outcomes, and the interaction between stress and cue reactivity will be presented, with a focus on new functional MRI results. An overview will be given on the concepts of impulsivity and compulsivity in pathological gambling and relevant neurocognitive and neuroimaging findings. Implications of neurobiological research for novel intervention research, such as in neuromodulation studies and personalized medicine will be highlighted.

The authors have not supplied their declaration of competing interest.

While DSM-5 classified pathological gambling as an addictive disorder, there is debate as to whether ICD-11 should follow suit. The debate hinges on scientific evidence such as neurobiological findings, family history of psychiatric disorders, psychiatric comorbidity, and personality variables.

In the “Baden-Württemberg Study of Pathological Gambling”, we compared a group of 515 male pathological gamblers receiving treatment with 269 matched healthy controls. We studied differences in sociodemographic characteristics, gambling-related variables, psychiatric comorbidity (lifetime), family history of psychiatric conditions, as well as personality traits such as impulsivity (Barratt Impulsiveness Scale), sensation seeking (Zuckerman's Sensation Seeking Scale) and the NEO-FFI big five. Personality traits were validated in an age- and ethnicity-matched subsample of “pure” gamblers without any psychiatric comorbidity (including nicotine dependence). Data were analyzed using two-sample t-tests, Chi2 analyses, Fisher's exact test and Pearson correlation analysis, as appropriate. Bonferroni correction was applied to correct for multiple comparisons.

Only 1% of the gamblers had been diagnosed with an impulse control disorder other than gambling (ICD-10). Notably, 88% of the gamblers in our sample had a comorbid diagnosis of substance dependence. The highest axis I comorbidity rate was for nicotine dependence (80%), followed by alcohol dependence (28%). Early age of first gambling experience was correlated with gambling severity. Compared to first-degree relatives of controls, first-degree relatives of pathological gamblers were more likely to suffer from alcohol dependence (27.0% vs. 7.4%), pathological gambling (8.3% vs. 0.7%) and suicide attempts (2.7% vs. 0.4%). Significant group differences were observed for the NEO-FFI factors neuroticism, agreeableness and conscientiousness. Gamblers were also more impulsive than controls, but did not differ from controls in terms of sensation seeking.

Our findings support classifying pathological gambling as a behavioural addiction in the ICD-11. This decision will have a significant impact on the approaches available for prevention (e.g. age limits) and treatment.

The purpose of the present study was to test whether individuals with Internet addiction disorder (IAD) presented analogous characteristics of working memory, executive function and impulsivity compared with pathological gambling (PG) patients.

The subjects included 23 individuals with IAD, 23 PG patients and 23 controls. All of the participants were measured with the digit span task, Wisconsin Card Sorting Test, go/no-go task and Barratt Impulsiveness Scale-11 (BIS-11) under the same experimental conditions.

The results of this study showed that the false alarm rate, total response errors, perseverative errors, failure to maintain set and BIS-11 scores of both the IAD and PG groups were significantly higher than that of the control group. In addition, the forward scores and backwards scores, percentage of conceptual level responses, number of categories completed and hit rate of the IAD and PG groups were significantly lower than that of the control group. Furthermore, the false alarm rate and BIS-11 scores of the IAD group were significantly higher than those of PG patients, and the hit rate was significantly lower than that of the PG patients.

Individuals with IAD and PG patients present deficiencies in working memory, executive dysfunction and impulsivity, and individuals with IAD are more impulsive than PG patients.

To evaluate the impaired attention selection (Stroop interference effect) and general performance [reaction times (RTs)] on the Stroop task among methadone maintenance treatment (MMT) patients with obsessive compulsive disorder (OCD), pathological gambling (PG), both PG/OCD or none, and the influence if having ADHD.

Eighty-six patients and 15 control subjects underwent the Stroop task, which measured RTs of condition-related words (color, obsessive compulsive disorder, pathological gambling, addiction) and neutral words.

MMT patients had longer RTs on the Stroop task compared with controls. RTs were longer among patients with OCD and in those who abused drugs on the study day. The combined PG/OCD group had the longest RTs, but they were also characterized as abusing more drugs, being older, and having worse cognitive status. Stroop color interference differed only among MMT patients with ADHD, and it was higher among those with OCD than those without OCD. The modified condition-related Stroop did not show any interference effect of OCD, addiction, or gambling words.

MMT patients had generally poorer performance, as indicated by longer RTs, that were related to clinical OCD, drug abuse, poor cognitive state, and older age. Patients with both clinical OCD and ADHD had a higher Stroop interference effect, which is a reflection of an attention deficit. In order to improve clinical approach and treatment of MMT patients, OCD and ADHD should be evaluated (and treated as needed).

Pathological gambling (PG) is a severe and persistent pattern of problem gambling that has been aligned with obsessive-compulsive disorder (OCD). However, no study has compared the neurocognitive profiles of individuals with PG and OCD.

We compared neurocognitive functioning, including executive function, verbal learning and memory, and visual–spatial organization and memory among 16 pathological gamblers, 31 drug-naïve OCD subjects, and 52 healthy controls.

The only neurocognitive marker common to both groups was increased fragmentation errors on the Rey–Osterrieth Complex Figure Test (ROCF). The PG subjects showed increased nonperseverative error on the Wisconsin Card Sorting Test and organization difficulties in the ROCF, whereas the OCD subjects revealed longer response times on the Stroop test and retention difficulties on the immediate recall scale of the ROCF.

A more careful approach is required in considering whether PG is a part of the OCD spectrum, as little evidence of neurocognitive overlap between PG and OCD has been reported.

When gambling opportunities are made available to the public in a given jurisdiction, some individuals participate occasionally and others more frequently. Among frequent gamblers, some individuals develop problematic involvement and some do not. This study addresses the association among demographic and social risk factors, frequency of gambling and gambling disorders.

Data from an adult community sample (n=1372) were used to identify risk factors for higher-frequency gambling and disordered gambling involvement.

Individuals with higher intelligence, older individuals and more religious individuals were less frequent gamblers. Males, single individuals and those exposed to gambling environments (friends and family who gamble) and those who started to gamble at a younger age were more frequent gamblers. Excitement-seeking personality traits were also higher among more frequent gamblers. A different set of risk factors was associated with the likelihood of gambling disorder among these higher-frequency gamblers. These variables included mental health indicators, childhood maltreatment and parental gambling involvement. Among higher-frequency gamblers, individuals who smoke cigarettes, those with a diagnosis of alcohol or drug dependence or obsessive–compulsive disorder, those with higher anxiety or depression and those with higher impulsivity and antisocial personality traits were more likely to report gambling-related problems. These individuals were also more likely to report gambling on electronic gambling machines (e.g. slot machines).

These data suggest a model in which higher-frequency gambling, particularly with electronic gambling machines, when combined with any type of emotional vulnerability increased the likelihood of gambling disorder.

Relatively little is known about the environmental and genetic contributions to gambling frequency and disordered gambling (DG), the full continuum of gambling-related problems that includes pathological gambling (PG).

A web-based sample (n=43 799 including both members of 609 twin and 303 sibling pairs) completed assessments of number of lifetime gambling episodes, DSM-IV criteria for PG, alcohol, nicotine and caffeine intake, and nicotine dependence (ND) and DSM-III-R criteria for lifetime major depression (MD). Twin modeling was performed using Mx.

In the entire cohort, symptoms of DG indexed a single dimension of liability. Symptoms of DG were weakly related to caffeine intake and moderately related to MD, consumption of cigarettes and alcohol, and ND. In twin and sibling pairs, familial resemblance for number of times gambled resulted from both familial–environmental (c2=42%) and genetic factors (a2=32%). For symptoms of DG, resemblance resulted solely from genetic factors (a2=83%). Bivariate analyses indicated a low genetic correlation between symptoms of DG and MD (ra=+0.14) whereas genetic correlations with DG symptoms were substantially higher with use of alcohol, caffeine and nicotine, and ND (ranging from +0.29 to +0.80). The results were invariant across genders.

Whereas gambling participation is determined by shared environmental and genetic factors, DG constitutes a single latent dimension that is largely genetically determined and more closely related to externalizing than internalizing behaviors. Because these findings are invariant across genders, they suggest that the etiological factors of DG are likely to be similar in men and women.