Antiparkinsonian medication and pathological gambling

Impulse control disorders associated with dopaminergic drugs: A disproportionality analysis using vigibase

BACKGROUND

Dopamine receptor agonist drugs, which are used, for example, to treat Parkinson's disease (PD), increase the risk for impulse control disorders (ICDs), potentially resulting in devastating psychosocial consequences. It is unknown whether other drugs with dopaminergic properties also increase the risk for ICDs. This study assesses the disproportionality of reporting ICDs between drugs with dopaminergic properties and selected non-dopaminergic drugs.

METHODS

A case/non-case disproportionality analysis was performed, using data from VigiBase (1968-2020). Reports on ICDs as suspected adverse drug reactions (ADRs) were cases (n=852), and those with ADRs other than ICDs were non-cases (n=281,720). Relative reporting frequencies were expressed as adjusted reporting odds ratios (aRORs). Within the dopamine receptor agonists, the relationship between reporting odds ratios and dopamine receptor occupancy was explored.

RESULTS

A high disproportionality was found for reporting ICDs for all dopaminergic drugs (aROR 20.4 [95% CI 17.4-24.1]) compared to non-dopaminergic drugs. In pharmacotherapeutic subgroups, a high disproportionality was found for primary dopaminergic agents used in PD (aROR 52.1 [95% CI 44.1-61.5]), and to a lesser extent for ADHD psychostimulants and antidepressants (aROR 5.8 [95% 4.1-8.3] and aROR 3.9 [95% CI 2.9-5.6], respectively). There was no difference in reporting by consumers and healthcare professionals. The highest disproportionality was found for the dopamine receptor agonists pramipexole and ropinirole.

CONCLUSIONS

A signal of disproportion in ICD occurrence was found among all investigated drugs with dopaminergic properties, highlighting the importance of counselling and monitoring for ICDs when prescribing dopaminergic drugs.

Testing the Validity of the Pathways Model: A Latent Class Analysis of Potential Pathological Gambling Subtypes in a Non-Treatment Sample

Latent class analysis (LCA) was used to test the validity of the Pathways Model in 285 subjects with DSM-IV pathological gambling (PG). In addition to identifying three subtypes that roughly correspond with those described in the model (Behaviorally Conditioned, or BC, Emotionally Vulnerable, or EV, Antisocial-Impulsivist, or AI), LCA identified a fourth class, termed the Antisocial Drinker, or AD, characterized by high rates of antisociality, conduct disorder, and alcohol use disorder. BC gamblers comprised 45% of the sample, followed by EV (24%), AD (22%), and AI (9%) gamblers. Women were more likely to be EV gamblers (OR = 1.89) and less likely to be AD gamblers (OR = 0.46). Those who had attempted suicide were more likely to be EV (OR = 3.06) or AI (OR = 3.05) gamblers and less likely to be BC (OR = 0.37) or AD gamblers (OR = 0.50). Greater childhood maltreatment was associated with AD (standardized OR = 1.81) and AI (standardized OR = 1.43) gamblers. Individuals with later PG onset were less likely to be AI gamblers (standardized OR = 0.48). Individuals who preferred slots were more likely to be EV gamblers (OR = 1.83) and less likely to be AD gamblers (OR = 0.33). The BC subtype was associated with better health outcomes, better social functioning, less childhood maltreatment, and less severe PG. The AI subtype was associated with worse health outcomes, worse social functioning, and higher PG severity. The findings provide a better understanding PG heterogeneity that could be relevant to clinical management.

Problem Gambling Associated with Aripiprazole: A Nested Case-Control Study in a First-Episode Psychosis Program

BACKGROUND

Aripiprazole has been linked to cases of problem gambling (PBG), but evidence supporting this association remains preliminary. Additionally, data specific to PBG in individuals with first-episode psychosis (FEP) receiving aripiprazole are limited to a few case reports, even though aripiprazole is widely used among this population that might be especially vulnerable to PBG.

METHODS

To examine this association, a nested case-control study was conducted in a cohort of 219 patients followed at a FEP program located in the Quebec City, Quebec, Canada, metropolitan area. Fourteen cases meeting the PBG criteria according to the Problem Gambling Severity Index were identified and matched for gender and index date to 56 control subjects.

RESULTS

In the univariable conditional logistic regression analysis, the use of aripiprazole was associated with an increased risk of PBG (odds ratio [OR] 15.2; 95% confidence interval [CI] 2.1-670.5). Cases were more likely to have a prior gambling history (either recreational or problematic) than controls at admittance in the program; they were also more frequently in a relationship and employed. After adjustment for age, relationship status, employment and Cluster B personality disorders, the use of aripiprazole remained associated with an increased risk of PBG (OR 8.6 [95% CI 1.5-227.2]).

CONCLUSIONS

Findings from this study suggest that FEP patients with a gambling history, problematic or not, may be at increased risk of developing PBG when receiving aripiprazole. They also highlight the importance of systematically screening for PBG all individuals with psychotic disorders, as this comorbidity hinders recovery. While the results also add credence to a causal association between aripiprazole and PBG, further prospective studies are needed to address some of the limitations of this present study.

An Exploratory Analysis of Predictors of Course in Older and Younger Adults with Pathological Gambling: A Non-Treatment Sample

We examined the association of baseline social, demographic, and clinical predictor variables with course in 48 older (≥ 60 years) and 57 younger (< 40 years) subjects with pathological gambling (PG) in a prospective follow-up study. Weekly gambling activity was tracked and used to categorize PG course. Generalized estimating equation models were used to examine predictors of disordered (i.e., level 2 or 3) gambling. Interaction tests were used to test for differential relationships for older and younger subjects. Predictors of disordered gambling during follow-up included greater severity of PG symptoms, greater severity of depressive symptoms, self-reported childhood neglect, cognitive distortions related to games of chance, and more role limitations due to physical health. Interaction tests showed that the relationships between some risk factors and disordered gambling varied for older and younger adults. Understanding these interrelationships could allow clinicians to more effectively monitor and manage their patients with PG.

Are Comorbid Disorders Associated with Changes in Gambling Activity? A Longitudinal Study of Younger and Older Subjects with DSM-IV Pathological Gambling

This study investigates the association of comorbid disorders with gambling activity in a longitudinal follow-up study of younger and older adult subjects with DSM-IV pathological gambling (PG). The subjects included 57 younger adults with PG (≥ 18/ < 40 years) and 48 older adults with PG (≥ 60 years). Subjects were assessed at baseline and every 6 months for a mean (SD) of 31.4 (13.1) months. Comorbidity was assessed using a modification of the Longitudinal Interval Follow-up Evaluation (LIFE). During follow-up, rates of problem severity were highest for anxiety disorders, mood disorders, and impulse control disorders. Among all subjects with PG, greater severity of depression or posttraumatic stress disorder was associated with increased gambling activity. In older subjects, greater severity of agoraphobia and social phobia were associated with lowered gambling activity. In younger subjects, greater severity of any substance use disorder, an alcohol use disorder, or compulsive computer use were associated with lowered gambling activity. The latter findings provide presumptive evidence for the substitute addiction hypothesis. We conclude that increased severity of several comorbid disorders could serve as triggers for increased gambling or predict lowered gambling activity. On the other hand, certain comorbid disorders could be triggered by increased gambling activity. Knowing these interrelationships is important to gaining a better understanding of PG and its clinical management.

Religiosity and Chance Beliefs in Persons with DSM-IV Pathological Gambling Enrolled in a Longitudinal Follow-Up Study

This study investigates the association of public, private and intrinsic religiosity and chance beliefs (superstition, illusion of control) with gambling behavior in a longitudinal follow-up study of younger and older adult subjects with DSM-IV pathological gambling (PG) and an older adult comparison group without PG. One-hundred sixty-three subjects were enrolled including 60 younger adults with PG (≥ 18/< 40 years), 53 older adults with PG (≥ 60 years), and 50 older adults without PG (≥ 60). Subjects were assessed at baseline and every 6 months thereafter. The Duke University Religion Index for Religious Assessment and the Drake Beliefs About Chance scales were administered at baseline. Follow-up was a mean (SD) of 2.6 (1.4) years. Older adults with PG scored lower on measures of public and intrinsic aspects of religiosity than older adults without PG, and scored higher on superstition and illusion of control. Older adults with PG also scored higher than younger adults with PG on private and intrinsic religiosity, but not public religiosity. Superstition predicted intrinsic, but not other aspects of religiosity. Importantly, during follow-up, higher levels of public and intrinsic religiosity were protective against problematic (levels 2, 3) gambling; were protective against chronic PG; and were predictive of PG remission status. Lower illusion of control ratings were protective against problematic gambling and chronic PG; lower superstition ratings were predictive of remission. We conclude that higher levels of public and intrinsic religiosity and lower levels of chance beliefs are associated with a more benign PG course.

Impulse-Control Disorders in Parkinson's Disease: A Meta-Analysis and Review of Case-Control Studies

BACKGROUND

Although several case-control studies on the prevalence of Impulse-Control Disorders (ICDs) in Parkinson's Disease (PD) have been conducted, no meta-analytic study on this topic has previously been published. Thus, knowledge about the overall prevalence rate of ICD in PD and factors that might moderate this relationship is lacking.

METHOD

Prevalence studies of ICDs in PD were identified by computer searches in the MEDLINE, PsycINFO, and Web of Science databases, covering the period from January 2000 to February 2017. Data for N = 4,539, consisting of 2,371 PD patients and 2,168 healthy controls, representing 14 case-control studies were included. Estimation of the odds ratio (OR) of ICDs in PD compared to healthy controls was conducted using random-effects models. Mixed-effects models were applied in the moderator analysis of heterogeneity. Publication bias was estimated using a contour-enhanced funnel plot, the Rüker's test, and fail-safe N test for estimating the number of potential missing studies.

RESULTS

Overall, the results showed significantly higher ratios for several ICDs in PD compared to healthy controls with the estimated overall ORs ranging between 2.07, 95% CI [1.26, 3.48], for having any ICDs, and 4.26, 95% CI [2.17, 8.36], for hypersexuality. However, the random-effects results for shopping were non-significant, though the fixed-effects model was significant (OR = 1.66, 95%CI [1.21, 2.27]). The testing of potential moderator variables of heterogeneity identified the following two variables that were both associated with increased risk: being medically treated for PD and disease duration. The results must be interpreted with some caution due to possible small-studies effect or publication bias.

CONCLUSION

Individuals with PD seem to have a significantly greater risk of suffering from ICDs compared to healthy controls. Gambling, hypersexuality, eating, punding, and hobbying are all ICDs significantly associated with PDs being medically treated for PD.

A prospective follow-up study of younger and older subjects with pathological gambling

Pathological gambling (PG) is a common and costly public health problem associated with impaired quality of life and high suicide rates. Despite its frequency in the general population, PG course is poorly understood in older adults who are especially vulnerable to its devastating consequences. We enrolled 175 subjects in a longitudinal study of gambling behavior: our case group of 53 older adults with PG (≥ 60 years), and two comparison groups including 72 younger adults with PG (< 40 years) and 50 older adults without PG (≥ 60 years). Subjects with PG met lifetime criteria for DSM-IV PG and had a South Oaks Gambling Screen (SOGS) and National Opinion Research Center DSM Screen for Gambling Problems (NODS) scores ≥ 5. Subjects were evaluated at intake and reassessed every 6 months and drop outs were replaced. Follow-up lasted a mean (SD) of 2.6 (1.4) years. At intake older PGs were more likely to be female, Caucasian, divorced, and to have a lower level of education. Older and younger PGs were similar in gambling severity, but older PGs were more likely to have sought PG treatment. Older PGs had lower rates of lifetime drug use disorders, attention deficit/hyperactivity disorder, and obsessive-compulsive disorder. They preferred slots, were more likely to receive PG treatment, and were less likely to discontinue participation in the study. Week by week gambling activity levels showed a significant general downward movement for older and younger PGs, although there were no differences between the groups. Elders without PG had no change in their level of gambling activity. We conclude that younger and older PGs moved toward a reduced level of gambling activity during follow-up. Our data challenge the notion that PG is chronic and progressive.

Synthesis, Molecular Properties Estimations, and Dual Dopamine D2 and D3 Receptor Activities of Benzothiazole-Based Ligands

Neurleptic drugs, e.g., aripiprazole, targeting the dopamine D_2S and D₃ receptors (D_2SR and D₃R) in the central nervous system are widely used in the treatment of several psychotic and neurodegenerative diseases. Therefore, a new series of benzothiazole-based ligands (3-20) was synthesized by applying the bioisosteric approach derived from the selective D₃Rs ligand BP-897 (1) and its structurally related benz[d]imidazole derivative (2). Herein, introduction of the benzothiazole moiety was well tolerated by D_2SR and D₃R binding sites leading to antagonist affinities in the low nanomolar concentration range at both receptor subtypes. However, all novel compounds showed lower antagonist affinity to D₃R when compared to that of 1. Further exploration of different substitution patterns at the benzothiazole heterocycle and the basic 4-phenylpiperazine resulted in the discovery of high dually acting D_2SR and D₃R ligands. Moreover, the methoxy substitution at 2-position of 4-phenylpiperazine resulted in significantly (22-fold) increased D_2SR binding affinity as compared to the parent ligand 1, and improved physicochemical and drug-likeness properties of ligands 3-11. However, the latter structural modifications failed to improve the drug-able properties in ligands having un-substituted 4-phenylpiperazine analogs (12-20). Accordingly, compound 9 showed in addition to high dual affinity at the D_2SR and D₃R [K_i (hD_2SR) = 2.8 ± 0.8 nM; K_i (hD₃R) = 3.0 ± 1.6 nM], promising clogS, clogP, LE (hD_2SR, hD₃R), LipE (hD_2SR, hD₃R), and drug-likeness score values of −4.7, 4.2, (0.4, 0.4), (4.4, 4.3), and 0.7, respectively. Also, the deaminated analog 10 [K_i (hD_2SR) = 3.2 ± 0.4 nM; K_i (hD₃R) = 8.5 ± 2.2 nM] revealed clogS, clogP, LE (hD_2SR, hD₃R), LipE (hD_2SR, hD₃R) and drug-likeness score values of −4.7, 4.2, (0.4, 0.4), (3.9, 3.5), and 0.4, respectively. The results observed for the newly developed benzothiazole-based ligands 3-20 provide clues for the diversity in structure activity relationships (SARs) at the D_2SR and D₃R subtypes.

Dopamine Agonists: Time Pattern of Adverse Effects Reporting in Australia

BACKGROUND

In Australia, there is voluntary reporting of suspected adverse events (AEs) of therapeutic medicines. Some dopamine agonists (DAs) have serious AEs.

OBJECTIVE

We aimed to explore the pattern of DA AE reporting over two decades.

METHODS

We analysed AE case line listings obtained from the Australian Committee on the Safety of Medicines (ACSOM) for bromocriptine, cabergoline, pergolide, pramipexole and ropinirole, and related these to drug utilisation data (1992-2012). We noted the AE nature, frequency, onset, novelty, severity and outcome.

RESULTS

The 220 suspected AEs fell into five categories: (i) syncopal/pre-syncopal, (ii) fibrotic, (iii) psychotic, (iv) obsessive-compulsive behaviours (OCB) and (v) increased sleep. There were differential lag times between initial individual drug registration and reporting of suspected AEs, with a lag of at least one year for fibrotic reactions and OCB compared to more contemporaneous reporting of other AEs. Consistent with the published literature, ACSOM data showed that ergot DAs share fibrotic reactions as a class AE, whereas symptomatic hypotensive reactions, psychosis and OCB occurred in both ergot and non-ergot DAs, cabergoline and pramipexole, respectively. Reports of syncopal and pre-syncopal reactions seemed to diminish as ergot-based DA use declined. Levodopa was taken simultaneously with DAs in 87 instances. Of those treated, 92 % were 50 years or older. Parkinson's disease accounted for 89 % of use (119 reports).

CONCLUSIONS

Exploring the temporal relationship between post-marketing AE reporting and utilisation data, as exemplified by DAs, can be a valuable pharmacovigilance tool to encourage targeted adverse event monitoring and reporting.

The challenge of understanding the brain: where we stand in 2015

Starting with the work of Cajal more than 100 years ago, neuroscience has sought to understand how the cells of the brain give rise to cognitive functions. How far has neuroscience progressed in this endeavor? This Perspective assesses progress in elucidating five basic brain processes: visual recognition, long-term memory, short-term memory, action selection, and motor control. Each of these processes entails several levels of analysis: the behavioral properties, the underlying computational algorithm, and the cellular/network mechanisms that implement that algorithm. At this juncture, while many questions remain unanswered, achievements in several areas of research have made it possible to relate specific properties of brain networks to cognitive functions. What has been learned reveals, at least in rough outline, how cognitive processes can be an emergent property of neurons and their connections.

Licit and illicit drug use in cluster headache

Cluster headache patients seem to use more licit and illicit substances than the general population. The epidemiologic data supporting this is growing. We included the licit drugs in this review because their use seems to be driven by the same addiction mechanisms leading to illicit drug abuse. Some drugs may be used in an attempt to treat cluster headache, especially cocaine and hallucinogens. Drug exposure may also play a role in CH pathophysiology, as suggested by interesting data on tobacco use and second-hand smoke exposure. A common factor may contribute both to CH and drug use predisposition. Genetic factors may be at play, and the dopaminergic and orexinergic pathways could be targeted for future studies.

Dopaminergic influences on emotional decision making in euthymic bipolar patients

We recently reported that the D2/D3 agonist pramipexole may have pro-cognitive effects in euthymic patients with bipolar disorder (BPD); however, the emergence of impulse-control disorders has been documented in Parkinson's disease (PD) after pramipexole treatment. Performance on reward-based tasks is altered in healthy subjects after a single dose of pramipexole, but its potential to induce abnormalities in BPD patients is unknown. We assessed reward-dependent decision making in euthymic BPD patients pre- and post 8 weeks of treatment with pramipexole or placebo by using the Iowa Gambling Task (IGT). The IGT requires subjects to choose among four card decks (two risky and two conservative) and is designed to promote learning to make advantageous (conservative) choices over time. Thirty-four BPD patients completed both assessments (18 placebo and 16 pramipexole). Baseline performance did not differ by treatment group (F=0.63; p=0.64); however, at week 8, BPD patients on pramipexole demonstrated a significantly greater tendency to make increasingly high-risk, high-reward choices across the five blocks, whereas the placebo group's pattern was similar to that reported in healthy individuals (treatment × time × block interaction, p<0.05). Analyses of choice strategy using the expectancy valence model revealed that after 8 weeks on pramipexole, BPD patients attended more readily to feedback related to gains than to losses, which could explain the impaired learning. There were no significant changes in mood symptoms over the 8 weeks, and no increased propensity toward manic-like behaviors were reported. Our results suggest that the enhancement of dopaminergic activity influences risk-associated decision-making performance in euthymic BPD. The clinical implications remain unknown.

Effects of the 5HT2C antagonist SB242084 on the pramipexole-induced potentiation of water contrafreeloading, a putative animal model of compulsive behavior

RATIONALE

In rats, quinpirole, a dopaminergic D2/D3 receptor agonist, elicits both hyperdipsia and water "contrafreeloading" (CFL), a putative model of compulsivity. The role of D3 receptors in this effect remains unclear. Clomipramine (CIM) was found to contrast both hyperdipsia and CFL, but the role of serotonin in this effect requires further investigation.

OBJECTIVES

We studied the effects of the preferential D3 agonist pramipexole (PPX) in both models. Furthermore, we tested the sensitivity of PPX-induced CFL to CIM and to the 5HT2c antagonist SB242084.

METHODS

In experiment 1, drinking was measured at 2 and 5 h after eight daily injections of PPX (0 to 1.0 mg/kg intraperitoneally). In the CFL study, every other third lever press, the rat was reinforced by the delivery of water. On days 1-6, water was only available upon lever pressing. On days 7-15, choice between response-contingent and free access was provided. PPX doses as in the experiment 1 were given. In two further experiments, PPX (0.5 mg/kg) was administered alone or in combination with CIM (5 or 10 mg/kg) or SB242084 (0.3 or 1.0 mg/kg).

RESULTS

PPX did not produce hyperdipsia but enhanced spontaneous CFL. SB242084 attenuated PPX-induced CFL more effectively than CIM, restoring the preference for free access to water.

CONCLUSIONS

CFL, but not polydipsia, was induced by preferential D3 activation, an effect prevented by 5HT2c receptor blockade. Since PPX interferes with decision making and 5HT2c receptor supersensitivity is involved in the expression of compulsive behaviors, this study supports the compulsive nature of dopaminergic-induced CFL.

Receptor-specific modulation of risk-based decision making by nucleus accumbens dopamine

The nucleus accumbens (NAc) serves as an integral node within cortico-limbic circuitry that regulates various forms of cost-benefit decision making. The dopamine (DA) system has also been implicated in enabling organisms to overcome a variety of costs to obtain more valuable rewards. However, it remains unclear how DA activity within the NAc may regulate decision making involving reward uncertainty. This study investigated the contribution of different DA receptor subtypes in the NAc to risk-based decision making, assessed with a probabilistic discounting task. In well-trained rats, D1 receptor blockade with SCH 23,390 decreased preference for larger, uncertain rewards, which was associated with enhanced negative-feedback sensitivity (ie, an increased tendency to select a smaller/certain option after an unrewarded risky choice). Treatment with a D1 agonist (SKF 81,297) optimized decision making, increasing choice of the risky option when reward probability was high, and decreasing preference under low probability conditions. In stark contrast, neither blockade of NAc D2 receptors with eticlopride, nor stimulation of these receptors with quinpirole or bromocriptine influenced risky choice. In comparison, infusion of the D3-preferring agonist PD 128,907 decreased reward sensitivity and risky choice. Collectively, these results show that mesoaccumbens DA refines risk-reward decision biases via dissociable mechanisms recruiting D1 and D3, but not D2 receptors. D1 receptor activity mitigates the effect of reward omissions on subsequent choices to promote selection of reward options that may have greater long-term utility, whereas excessive D3 receptor activity blunts the impact that larger/uncertain rewards have in promoting riskier choices.

Neuropsychological performance, impulsivity, ADHD symptoms, and novelty seeking in compulsive buying disorder

We examined the neuropsychological performance of people with compulsive buying disorder (CBD) and control subjects, along with trait impulsivity, symptoms of attention deficit hyperactivity disorder (ADHD), and selected personality characteristics. Subjects received a comprehensive neuropsychological test battery, depression and ADHD symptom assessment, the Barratt Impulsiveness Scale, and a version of the Temperament and Character Inventory. Persons with CBD (n=26) and controls (n=32) were comparable in terms of age, sex, and years of education. Subjects with CBD had a mean age of 36.3 years (S.D.=15.7) and an age at onset of 19.7 years (S.D.=7.0). Compulsive buyers had more lifetime mood, anxiety, and impulse control disorders. People with Compulsive buying performed significantly better on the Wechsler Abbreviated Scale of Intelligence Picture Completion task, a test of visual perception; otherwise, there were no consistent differences in neuropsychological measures. They also had elevated levels of self-reported depression, ADHD symptoms, trait impulsivity, and novelty seeking. In conclusion, compulsive buyers have greater lifetime psychiatric comorbidity than controls, and higher levels of self-rated depression, ADHD symptoms, trait impulsivity, and novelty seeking. The present study does not support the notion that there is a pattern of neuropsychological deficits associated with CBD.

Jeu pathologique chez les patients atteints de la maladie de Parkinson

Le jeu pathologique consiste en une pratique inadaptée, persistante et répétée du jeu qui a des répercussions majeures sur les individus touchés, leur famille et la société (APA, 2003). Plusieurs facteurs de risque de nature biologique, psychologique et sociale ont été soulevés comme pouvant contribuer au jeu pathologique. Une nouvelle population à risque a récemment été découverte : les patients atteints de la Maladie de Parkinson. Le développement d’un jeu pathologique chez ces patients serait principalement relié à une médication associée au traitement de la Maladie de Parkinson, les agonistes dopaminergiques. Bien qu’une recrudescence d’études neurologiques qui s’intéressent à ce phénomène ait été notée, peu d’intervenants semblent être au courant de cette problématique et peu de recherches ont été réalisées afin d’étudier les aspects psychologiques de cette problématique.

A comparison of gambling behavior, problem gambling indices, and reasons for gambling among smokers and nonsmokers who gamble: evidence from a provincial gambling prevalence study

INTRODUCTION

Numerous epidemiological and clinical studies have found that tobacco use and gambling frequently cooccur. Despite high rates of smoking among regular gamblers, the extent to which tobacco potentially influences gambling behavior and vice versa is poorly understood. The current study aimed to provide more insight into this relationship by directly comparing nonsmoking and smoking gamblers on gambling behavior, problem gambling indices, and reasons for gambling.

METHODS

The data for this study came from the 2005 Newfoundland and Labrador Gambling Prevalence Study. Gamblers identified as nonsmokers (N = 997) were compared with gamblers who smoke (N = 622) on numerous gambling-related variables. Chi-square analyses were used to compare groups on demographic variables. Associations between smoking status and gambling criteria were assessed with a series of binary logistic regressions.

RESULTS

The regression analyses revealed several significant associations between smoking status and past 12-month gambling. Higher problem gambling severity scores, use of alcohol/drugs while gambling, amount of money spent gambling, use of video lottery terminals, and reasons for gambling which focused on positive reinforcement/reward and negative reinforcement/relief were all associated with smoking.

CONCLUSIONS

The findings suggest an association between smoking and potentially problematic gambling in a population-based sample. More research focused on the potential reinforcing properties of tobacco on the development and treatment of problematic gambling is needed.

Cognitive-behavioral therapy for pathological gambling in Parkinson's disease: a pilot controlled study

OBJECTIVES

The main objective of this study was to compare the clinical characteristics and differences in response to treatment of two groups of pathological gamblers: with comorbid Parkinson's disease (PG + PD) and without (PG - PD).

METHODS

Clinical and psychopathological profiles and response to cognitive-behavioral treatment were assessed in 15 PG + PD and 45 PG - PD individuals consulting a specialized hospital Unit.

RESULTS

Statistically significant differences were observed between the two groups on a series of clinical variables. PG + PD patients were older and presented later onset of problematic gambling behaviors, lower alcohol consumption and higher bingo playing than PG - PD patients. No significant differences were noted in psychopathology except for lower measures of hostility in the PG + PD group. No statistical differences were detected between groups in terms of response to treatment.

CONCLUSION

These results may provide guidance for obtaining accurate diagnostic information in pathological gamblers by properly identifying patients with specific needs that may be targeted with treatment.

Natural rewards, neuroplasticity, and non-drug addictions

There is a high degree of overlap between brain regions involved in processing natural rewards and drugs of abuse. "Non-drug" or "behavioral" addictions have become increasingly documented in the clinic, and pathologies include compulsive activities such as shopping, eating, exercising, sexual behavior, and gambling. Like drug addiction, non-drug addictions manifest in symptoms including craving, impaired control over the behavior, tolerance, withdrawal, and high rates of relapse. These alterations in behavior suggest that plasticity may be occurring in brain regions associated with drug addiction. In this review, I summarize data demonstrating that exposure to non-drug rewards can alter neural plasticity in regions of the brain that are affected by drugs of abuse. Research suggests that there are several similarities between neuroplasticity induced by natural and drug rewards and that, depending on the reward, repeated exposure to natural rewards might induce neuroplasticity that either promotes or counteracts addictive behavior.

Effects of acute pramipexole on preference for gambling-like schedules of reinforcement in rats

RATIONALE

Pramipexole and other direct dopamine agonist medications have been implicated in the development of impulsive behavior such as pathological gambling among those taking the drug to control symptoms of Parkinson's disease or restless leg syndrome. Few laboratory studies examining pramipexole's effects on gambling-like behavior have been conducted.

OBJECTIVES

The present study used a rodent model approximating some aspects of human gambling to examine within-subject effects of acute pramipexole (0.03, 0.1, 0.18, and 0.3 mg/kg) on rat's choices to earn food reinforcement by completing variable-ratio (VR; i.e., gambling-like) or fixed-ratio (FR) response requirements.

RESULTS

In a condition in which the VR alternative was rarely selected, all but the lowest dose of pramipexole significantly increased choice of the VR alternative (an average of 15% above saline). The same doses did not affect choice significantly in a control condition designed to evaluate the involvement of nonspecific drug effects. Pramipexole increased latencies to initiate trials (+9.12 s) and to begin response runs on forced-choice trials (VR = +0.21 s; FR = +0.88 s), but did not affect measures of response perseveration (conditional probabilities of "staying").

CONCLUSIONS

The findings are consistent with clinical reports linking pramipexole to the expression of increased gambling in humans. Results are discussed in the context of neurobehavioral evidence suggesting that dopamine agonists increase sensitivity to reward delay and disrupt appropriate feedback from negative outcomes.

Differential induction of adenylyl cyclase supersensitivity by antiparkinson drugs acting as agonists at dopamine D1/D2/D3 receptors vs D2/D3 receptors only: parallel observations from co-transfected human and native cerebral receptors

Though there is evidence that sustained exposure of dopamine (DA) receptors to agonists can elicit a supersensitivity of adenylyl cyclase (AC), little is known about the pharmacological characteristics of this phenomenon, and possible interrelationships amongst DA receptor subtypes have not been examined. In cells co-transfected with D(1) plus D(2), or D(1) plus D(3), receptors, which are known to physically and functionally interact, long-term exposure to quinpirole, pramipexole and ropinirole (which possess negligible affinities for D(1) sites) elicited supersensitivity of D(1) receptor-activated AC. By contrast, D(2)/D(3) receptor agonists that also act as D(1) receptor agonists, bromocriptine, lisuride, cabergoline, apomorphine and DA itself, did not elicit supersensitivity. Interestingly, AC supersensitivity was also observed in the nucleus accumbens of mice pretreated with twice-daily pramipexole and quinpirole, whereas no change was seen either with lisuride or with the DA precursor, L-DOPA. Thus, AC supersensitivity is elicited by the sustained exposure of cloned human and native mouse populations of dopaminergic receptors, to D(2)/D(3) but not D(1)/D(2)/D(3) agonists. These observations may be related to the exacerbation of gambling in Parkinson's disease that is provoked by antiparkinson agents acting as selective D(2)/D(3) receptor agonists, notably pramipexole.

Health-related quality of life in Parkinson disease: correlation between Health Utilities Index III and Unified Parkinson's Disease Rating Scale (UPDRS) in U.S. male veterans

Objective

To apply a scaled, preference-based measure to the evaluation of health-related quality of life (HRQoL) in Parkinson's disease (PD); to evaluate the relationship between disease-specific rating scales and estimated HRQoL; and to identify predictors of diminished HRQoL.

Background

Scaled, preference-based measures of HRQoL ("utilities") serve as indices of impact of disease, and can be used to generate quality-adjusted estimates of survival for health-economic evaluations. Evaluation of utilities for PD and their correlation with standard rating scales have been limited.

Methods

Utilities were generated using the Health Utilities Index Mark III (HUI-III) on consecutive patients attending a PD Clinic between October 2003 and June 2006. Disease severity, medical, surgical (subthalamic nucleus deep brain stimulation (STN-DBS)), and demographic information were used as model covariates. Predictors of HUI-III utility scores were evaluated using the Wilxocon rank-sum test and linear regression models.

Results

68 men with a diagnosis of PD and a mean age of 74.0 (SD 7.4) were included in the data analysis. Mean HUI-III utility at first visit was 0.45 (SD 0.33). In multivariable models, UPDRS-II score (r² = 0.56, P < 0.001) was highly predictive of HRQoL. UPDRS-III was a weaker, but still significant, predictor of utility scores, even after adjustment for UPDRS-II (P = 0.01).

Conclusions

Poor self-care in PD reflected by worsening UPDRS-II scores is strongly correlated with low generic HRQoL. HUI-III-based health utilities display convergent validity with the UPDRS-II. These findings highlight the importance of measures of independence as determinants of HRQoL in PD, and will facilitate the utilization of existing UPDRS data into economic analyses of PD therapies.

From the cell to the clinic: a comparative review of the partial D₂/D₃receptor agonist and α2-adrenoceptor antagonist, piribedil, in the treatment of Parkinson's disease

Though L-3,4-dihydroxyphenylalanine (L-DOPA) is universally employed for alleviation of motor dysfunction in Parkinson's disease (PD), it is poorly-effective against co-morbid symptoms like cognitive impairment and depression. Further, it elicits dyskinesia, its pharmacokinetics are highly variable, and efficacy wanes upon long-term administration. Accordingly, "dopaminergic agonists" are increasingly employed both as adjuncts to L-DOPA and as monotherapy. While all recognize dopamine D(2) receptors, they display contrasting patterns of interaction with other classes of monoaminergic receptor. For example, pramipexole and ropinirole are high efficacy agonists at D(2) and D(3) receptors, while pergolide recognizes D(1), D(2) and D(3) receptors and a broad suite of serotonergic receptors. Interestingly, several antiparkinson drugs display modest efficacy at D(2) receptors. Of these, piribedil displays the unique cellular signature of: 1), signal-specific partial agonist actions at dopamine D(2)and D(3) receptors; 2), antagonist properties at α(2)-adrenoceptors and 3), minimal interaction with serotonergic receptors. Dopamine-deprived striatal D(2) receptors are supersensitive in PD, so partial agonism is sufficient for relief of motor dysfunction while limiting undesirable effects due to "over-dosage" of "normosensitive" D(2) receptors elsewhere. Further, α(2)-adrenoceptor antagonism reinforces adrenergic, dopaminergic and cholinergic transmission to favourably influence motor function, cognition, mood and the integrity of dopaminergic neurones. In reviewing the above issues, the present paper focuses on the distinctive cellular, preclinical and therapeutic profile of piribedil, comparisons to pramipexole, ropinirole and pergolide, and the core triad of symptoms that characterises PD-motor dysfunction, depressed mood and cognitive impairment. The article concludes by highlighting perspectives for clarifying the mechanisms of action of piribedil and other antiparkinson agents, and for optimizing their clinical exploitation.

Effects of pramipexole on impulsive choice in male wistar rats

Clinical reports, primarily with Parkinson's disease patients, note an association between the prescribed use of pramipexole (and other direct-acting dopamine agonist medications) and impulse control disorders, particularly pathological gambling. Two experiments examined the effects of acute pramipexole on rats' impulsive choices where impulsivity was defined as selecting a smaller-sooner over a larger-later food reward. In Experiment 1, pramipexole (0.1 to 0.3 mg/kg) significantly increased impulsive choices in a condition in which few impulsive choices were made during a stable baseline. In a control condition, in which impulsive choices predominated during baseline, pramipexole did not significantly change the same rats' choices. Experiment 2 explored a wider range of doses (0.01 to 0.3 mg/kg) using a choice procedure in which delays to the larger-later reinforcer delivery increased across trial blocks within each session. At the doses used in Experiment 1, pramipexole shifted choice toward indifference regardless of the operative delay. At lower doses of pramipexole (0.01 and 0.03 mg/kg), a trend toward more impulsive choice was observed at the 0.03 mg/kg dose. The difference in outcomes across experiments may be due to the more complex discriminations required in Experiment 2, that is, multiple discriminations between changing delays within each session.

Impulse control disorder and piribedil: report of 5 cases

Recent studies suggest that impulse control disorders (ICD) in Parkinson disease are not uncommon, and antiparkinsonian therapy, mainly the use of dopaminergic agonists, plays a causal role in the development of these symptoms. Pramipexole has been mainly related to the occurrence of ICDs, although these disorders may occur when any dopaminergic agonist-based therapy is administered.In this paper, we describe 4 patients with Parkinson disease and 1 with multisystem atrophy who presented a history (several months or years) of pathological gambling, hypersexuality, punding, and pathological use of the Internet secondary to piribedil. This previously undescribed association suggests that the development of these disorders might be also related to piribedil administration. It is also the first report of a patient with multisystem atrophy developing such adverse effects.

Decreased binding of the D3 dopamine receptor-preferring ligand [11C]-(+)-PHNO in drug-naive Parkinson's disease

The D(3) dopamine (DA) receptor is a member of the D(2)-like DA receptor family. While the D(2) receptor is abundant especially in motor-regions of the striatum, the D(3) receptor shows a relative abundance in limbic regions and globus pallidus. This receptor is of current interest in neurology because of its potential involvement in psychiatric and motor complications in Parkinson's disease and the possibility that dopamine D(3)-preferring agonist therapy might delay progression of the disorder. Preclinical data indicate that striatal levels of the D(3) (but not the D(2)) DA receptor are decreased following lesion of nigrostriatal DA neurons; at present, there are no in vivo data on this receptor subtype in Parkinson's disease. The objective of this positron emission tomography study was to compare [(11)C]-(+)-PHNO (D(3) versus D(2) preferring) and [(11)C]raclopride (D(3) = D(2)) binding in brain of non-depressed, non-demented, dopaminergic drug-naïve patients with early-stage Parkinson's disease (n = 10), relative to matched-controls (n = 9). Parkinson's disease was associated with a trend for bilaterally decreased [(11)C]-(+)-PHNO (but not [(11)C]raclopride) binding in the D(3)-rich ventral striatum (-11%, P = 0.07) and significantly decreased binding in globus pallidus (-42%, P = 0.02). In contrast, in the primarily D(2)-populated putamen, both [(11)C]-(+)-PHNO (25%, P = 0.02) and [(11)C]raclopride (25%, P < 0.01) binding were similarly increased, especially on the side contra-lateral to the symptoms. In the midbrain, presumably containing D(3) receptors localized to the substantia nigra, [(11)C]-(+)-PHNO binding was normal. Decreased [(11)C]-(+)-PHNO to [(11)C]raclopride ratio correlated with motor deficits and lowered-mood (P < 0.02). Our imaging data suggest that brain DA neuron loss in the human causes region-specific differential changes in DA D(2) and D(3) receptors with D(3) receptor 'downregulation' possibly related to some motor and mood problems in Parkinson disease. D(3) receptor levels might be a determinant vulnerability factor underlying side-effects associated with treatment; hence, these initial findings provide valuable baseline information to understand the role of D(3) receptors in response to Parkinson's disease medication.