Clinical features and comorbidity of mood fluctuations in Parkinson's disease

Anxiety in synucleinopathies: neuronal circuitry, underlying pathomechanisms and current therapeutic strategies

Synucleinopathies are neurodegenerative disorders characterized by alpha-synuclein (αSyn) accumulation in neurons or glial cells, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). αSyn-related pathology plays a critical role in the pathogenesis of synucleinopathies leading to the progressive loss of neuronal populations in specific brain regions and the development of motor and non-motor symptoms. Anxiety is among the most frequent non-motor symptoms in patients with PD, but it remains underrecognized and undertreated, which significantly reduces the quality of life for patients. Anxiety is defined as a neuropsychiatric complication with characteristics such as nervousness, loss of concentration, and sweating due to the anticipation of impending danger. In patients with PD, neuropathology in the amygdala, a central region in the anxiety and fear circuitry, may contribute to the high prevalence of anxiety. Studies in animal models reported αSyn pathology in the amygdala together with alteration of anxiety or fear learning response. Therefore, understanding the progression, extent, and specifics of pathology in the anxiety and fear circuitry in synucleinopathies will suggest novel approaches to the diagnosis and treatment of neuropsychiatric symptoms. Here, we provide an overview of studies that address neuropsychiatric symptoms in synucleinopathies. We offer insights into anxiety and fear circuitry in animal models and the current implications for therapeutic intervention. In summary, it is apparent that anxiety is not a bystander symptom in these disorders but reflects early pathogenic mechanisms in the cortico-limbic system which may even contribute as a driver to disease progression.

'Anxious fluctuators' a subgroup of Parkinson's disease with high anxiety and problematic on-off fluctuations

Anxiety that occurs in association with on-off dopamine medication fluctuations is a major cause of distress, dysfunction, and lower quality of life in people with Parkinson's disease (PD). However, the association between anxiety and on-off fluctuations is poorly understood and it is difficult to predict which patients will suffer from this atypical form of anxiety. To understand whether fluctuating anxiety in PD exists as part of an endophenotype that is associated with other signs or symptoms, we prospectively assessed the change in anxiety and a battery of clinical variables when transitioning from the off-dopamine medication state to the on state in 200 people with PD. We performed latent profile analysis with observed variables as latent profile indicators measuring the on-off-state difference in anxiety, depression, motor function, daily functioning, and the wearing off questionnaire 19 item scale (WOQ-19) in order to model unobserved (i.e., latent) profiles. A two-class model produced the best fit. The majority of participants, 69%, were categorized as having a 'typical on-off response' compared to a second profile constituting 31% of the sample who experienced a worsening in anxiety in the off state that was three times that of other participants. This profile referred to as "anxious fluctuators" had a Hamilton Anxiety Rating Scale change between the off and on medication state of 10.22(32.85) compared to 3.27 (7.62), higher depression scores, greater disability and was less likely to improve on select WOQ-19 items when in the on-state. Anxious fluctuators were more likely to be male and have a family history of anxiety disorder. Given the adverse impact of this profile we believe it may be important to distinguish patients with a typical on-off response from those with this more problematic course of fluctuations.

Phenomenology of Atypical Anxiety Disorders in Parkinson's Disease: A Systematic Review

OBJECTIVE

Anxiety is a prominent concern in Parkinson's disease (PD) that negatively impacts quality of life, increases functional disability, and complicates clinical management. Atypical presentations of anxiety are under-recognized and inadequately treated in patients with PD, compromising global PD care.

METHODS

This systematic review focuses on the prevalence, symptomology and clinical correlates of atypical presentations of PD-related anxiety following PRISMA guidelines.

RESULTS

Of the 60 studies meeting inclusion criteria, 14 focused on 'Anxiety Not Otherwise Specified (NOS)' or equivalent, 31 reported on fluctuating anxiety symptoms, and 22 reported on 'Fear of Falling (FOF)'. Anxiety NOS accounted for a weighted mean prevalence of 14.9%, fluctuating anxiety for 34.19%, and FOF for 51.5%. These latter two exceeded the average reported overall prevalence rate of 31% for anxiety disorders in PD. We identified a diverse array of anxiety symptoms related to motor and non-motor symptoms of PD, to complications of PD medication (such as "on" and "off" fluctuations, or both), and, to a lesser extent, to cognitive symptoms.

CONCLUSION

Atypical anxiety is common, clinically relevant, and heterogeneous in nature. A better understanding of the phenomenology, clinical course, and pathophysiology of varied forms of atypical anxiety in PD is needed to improve recognition, advance therapeutic development and ultimately optimize quality of life in PD.

Mood and emotional disorders associated with parkinsonism, Huntington disease, and other movement disorders

This chapter provides a review of mood, emotional disorders, and emotion processing deficits associated with diseases that cause movement disorders, including Parkinson's disease, Lewy body dementia, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, frontotemporal dementia with parkinsonism, Huntington's disease, essential tremor, dystonia, and tardive dyskinesia. For each disorder, a clinical description of the common signs and symptoms, disease progression, and epidemiology is provided. Then the mood and emotional disorders associated with each of these diseases are described and discussed in terms of clinical presentation, incidence, prevalence, and alterations in quality of life. Alterations of emotion communication, such as affective speech prosody and facial emotional expression, associated with these disorders are also discussed. In addition, if applicable, deficits in gestural and lexical/verbal emotion are reviewed. Throughout the chapter, the relationships among mood and emotional disorders, alterations of emotional experiences, social communication, and quality of life, as well as treatment, are emphasized.

Management of psychiatric disorders in Parkinson's disease : Neurotherapeutics - Movement Disorders Therapeutics

Affective disorders (depression and anxiety), psychosis, impulse control disorders, and apathy are common and sometimes disabling psychiatric conditions in Parkinson disease (PD). Psychiatric aspects of PD are associated with numerous adverse outcomes, yet in spite of this and their high frequency, there remains incomplete understanding of epidemiology, presentation, risk factors, neural substrate, and management strategies. Psychiatric features are typically co- or multimorbid, and there is great intra- and interindividual variability in presentation [1]. The neuropathophysiological changes that occur in PD, as well as the association between PD treatment and particular psychiatric disorders, suggest a neurobiological contribution to many psychiatric symptoms. There is evidence that psychiatric disorders in PD are still under-recognized and undertreated, and although psychotropic medication use is common, randomized controlled trials demonstrating efficacy and tolerability are largely lacking. Future research on neuropsychiatric complications in PD should be oriented toward determining modifiable correlates or risk factors, and most importantly, establishing efficacious and well-tolerated treatment strategies.

Subclinical affective and cognitive fluctuations in Parkinson's disease: a randomized double-blind double-dummy study of Oral vs. Intrajejunal Levodopa

BACKGROUND

Chronic levodopa treatment in Parkinson's disease (PD) may promote undesirable motor and non-motor fluctuations. Compared to chronic oral levodopa treatment, continuous infusion of levodopa/carbidopa intestinal gel (LCIG) in advanced PD reduces motor fluctuations. However, differences in their effect on acute non-motor changes were not formally demonstrated.

OBJECTIVE

We performed a randomized, double-blind, double-dummy, crossover study to compare acute non-motor changes between intermittent oral immediate-release carbidopa/levodopa (LC-IR) and LCIG.

METHODS

After > 12-h OFF, thirteen PD patients chronically treated with LCIG and without history of non-motor swings, were allocated to receive first, LCIG infusion plus three oral doses of placebo, or placebo infusion plus three oral doses of LC-IR. Over-encapsulated oral medication (LC-IR or placebo) was administered every 2 h. We monitored plasmatic levels of levodopa, motor status (UPDRS-III), mood, anxiety, and frontal functions at baseline (0-h) and hourly after each oral challenge.

RESULTS

Repeated-measures ANOVAs showed significant group by treatment interaction indicating more fluctuations of levodopa plasma levels with LC-IR. No significant interactions were seen in the temporal profile of motor status, anxiety, mood and cognition. However, point-to-point parametric and nonparametric tests showed a significant more marked and more sustained improvement in anxiety scores under LCIG. A significant improvement of mood and verbal fluency was seen a + 3-h only under LCIG.

DISCUSSION

Our sample of advanced PD patients exhibited moderate but significant non-motor fluctuations. LCIG was associated with a more favorable profile of acute affective and cognitive fluctuations that was particularly expressed at the first part of the infusion curve.

Perceived Treatment Status of Fluctuations in Parkinson Disease Impacts Suicidality

OBJECTIVE

On/off motor fluctuations in Parkinson disease (PD) can be associated with extreme mood fluctuations and severe dysphoria. The impact of these affective symptoms may be overlooked in the treatment of motor fluctuations. Our goal was to examine the relationship between motor fluctuations, their treatment status, and suicidality in PD participants.

METHODS

We analyzed data from the Methods of Optimal Depression Detection in Parkinson's Disease (MOOD-PD) study of 223 individuals with PD. Suicidality was measured using items from four depression scales: Hamilton Depression Rating Scale (HAM-D-17); Montgomery-Åsberg Depression Rating Scale (MADRS); Inventory for Depressive Symptomatology (IDS-C); and the self-rated Beck Depression Inventory (BDI). Multivariable Poisson regression analyses tested whether self-reported motor fluctuations and their treatment status were associated with suicidality while controlling for recognized risk factors.

RESULTS

Thirty-seven participants (16.6%) self-reported suicidality and 89 (39.5%) self-reported motor fluctuations, of whom 21 (23.6%) perceived their fluctuations as untreated. Participants reporting untreated motor fluctuations more frequently had a current depressive disorder (p < 0.001) and endorsed suicidality (p = 0.006) than participants with treated or no fluctuations. They also had significantly higher total scores on the HAM-D-17, MADRS, IDS-C, and BDI depression scales (p < 0.001 for each). Regression analyses showed significant associations between untreated motor fluctuations and higher scores on suicide questions extracted from the HAM-D-17, MADRS, and IDS-C (p < 0.01 for each).

CONCLUSIONS

PD patients with untreated motor fluctuations are at increased risk for suicidal thoughts and should be monitored for mood changes as treatment is adapted.

Emergence of non-motor fluctuations with reference to motor fluctuations in Parkinson's disease

INTRODUCTION

Non-motor fluctuations (NMF) and motor fluctuations (MF) are frequent in patients with Parkinson's disease (PD) with long-term medical treatment. We aimed to examine the timing of the emergence of NMF with reference to MF in a prospective cohort of patients with PD without symptom fluctuations.

METHODS

A total of 334 patients with PD who had neither MF nor NMF were recruited. The exclusion criteria included a Mini-Mental State Examination score of less than 26 points at baseline and an alternative diagnosis or significant comorbidity during follow-up. The "SNUH-Fluctuation Questionnaire" consisting of 29 items (9 on MF and 20 on NMF) was administered on a semi-annually basis for 3 years.

RESULTS

Three hundred seven out of 334 patients were analyzed for symptom fluctuations with the Kaplan-Meier survival analysis. MF were observed in more patients and developed earlier than NMF (cumulative survival of 0.572 for MF and 0.619 for NMF at 36 months of follow-up). In 212 patients who finished the follow-up for 36 months, MF and NMF developed simultaneously in 58 (27.4%), MF developed first in 45 (21.2%), and NMF developed first in only 3 (1.4%). The remaining 106 patients (50.0%) did not develop either MF or NMF.

CONCLUSION

NMF developed simultaneously with or later than MF. From these data, we hypothesize that NMF develop in the disease state where the pathology in the brain has been severe enough to develop MF. Hence, pharmacologic management should consider targeting both dopaminergic and non-dopaminergic systems to treat NMF.

Clinical Presentation of Anxiety in Parkinson's Disease: A Scoping Review

Up to 40% of all individuals with Parkinson's disease (PD) are estimated to experience anxiety that interferes with daily functioning. This article describes research regarding the presentation of anxiety in PD and the influence anxiety has on participation in this population. A scoping review identified 1,635 articles, of which 49 met the inclusion criteria. This review identified that anxiety in PD is often associated with a range of clinical correlates related to demographic and clinical characteristics (age, gender, disease stage, duration, progression), motor symptoms (tremor, bradykinesia, dystonia, freezing of gait, symptom severity), treatment-related complications (on/off fluctuations, on with dyskinesia, unpredictable off), and non-motor symptoms (sleep abnormalities, fatigue, cognitive impairment, depression). These findings can be used to increase clinicians' awareness toward the specific clinical correlates linked to anxiety in PD so that mental health concerns can be detected and addressed more readily in practice.

Virtually-induced threat in Parkinson's: Dopaminergic interactions between anxiety and sensory-perceptual processing while walking

Research evidence has suggested that anxiety influences gait in PD, with an identified dopa-sensitive gait response in highly anxious PD. It has been well-established that accurate perception of the environment and sensory feedback is essential for gait. Arguably since sensory and perceptual deficits have been noted in PD, anxiety has the potential to exacerbate movement impairments, since one might expect that reducing resources needed to overcome or compensate for sensory-perceptual deficits may lead to even more severe gait impairments. It is possible that anxiety in threatening situations might consume more processing resources, limiting the ability to process information about the environment or one's own movement (sensory feedback) especially in highly anxious PD. Therefore, the current study aimed to (i) evaluate whether processing of threat-related aspects of the environment was influenced by anxiety, (ii) evaluate whether anxiety influences the ability to utilize sensory feedback in PD while walking in threatening situations, and (iii) further understand the role of dopaminergic medication on these processes in threatening situations in PD. Forty-eight participants (24 HC; 12 Low Anxious [LA-PD], 12 Highly Anxious [HA-PD]) completed 20 walking trials in virtual reality across a plank that was (i) located on the ground (GROUND) (ii) located above a deep pit (ELEVATED); while provided with or without visual feedback about their lower limbs (+VF; -VF). After walking across the plank, participants were asked to judge the width of the plank they had just walked across. The plank varied in size from 60-100 cm. Both ON and OFF dopaminergic medication states were evaluated in PD. Gait parameters, judgment error and self-reported anxiety levels were measured. Results showed that HA-PD reported greater levels of anxiety overall (p<0.001) compared to HC and LA-PD, and all participants reported greater anxiety during the ELEVATED condition compared to GROUND (p=0.01). PD had similar judgment error as HC. Additionally, medication state did not significantly influence judgment error in PD. More importantly, HA-PD were the only group that did not adjust their step width when feedback was provided during the GROUND condition. However, medication facilitated a reduction in ST-CV when visual feedback was available only in the HA-PD group. Therefore, the current study provides evidence that anxiety may interfere with information processing, especially utilizing sensory feedback while walking. Dopaminergic medication appears to improve utilization of sensory feedback in stressful situations by reducing anxiety and/or improving resource allocation especially in those with PD who are highly anxious.

Behavioral effects of levodopa

In recent years, levodopa-induced behavioral changes have received increased attention in the medical literature and in clinical practice. The spectrum of these symptoms includes non-motor fluctuations with neuropsychiatric symptoms, compulsive behaviors such as punding, dopamine dysregulation syndrome, and impulse control disorders, psychosis and hallucinations, as well as hypomania and mania. Despite knowledge of the clinical features associated with these behaviors, many of them are probably underdiagnosed. Although the mechanisms underlying behavioral symptoms are still incompletely understood, recent data from imaging and pathological studies have increased our understanding and guided new treatment strategies. Appropriate management remains challenging, because reduction of levodopa (l-dopa) and dopaminergic treatment is often recommended; however, doses required for control of motor symptoms may still induce behavioral changes. Newer modes of delivery of dopaminergic treatment, deep brain stimulation, and nondopaminergic agents may either provide alternatives for treatment of these behavioral problems or permit treatment of parkinsonism with less risk of these behavioral disorders.

Anxiety in Parkinson's disease: identification and management

Anxiety disturbances are recognized as common psychiatric comorbidities in Parkinson's disease (PD) and contribute to significant impairments in areas of cognitive, functional, motor and social performance. Anxiety in PD results in reduced quality of life, higher levels of care dependency and increased caregiver burden. Surprisingly, there is a paucity of treatment data. In one randomized, controlled study, bromazepam was found to be effective for anxiety in PD. However, usage of benzodiazepines in the PD population is limited by potential risk of confusion and falls. There are no controlled studies of selective serotonin reuptake inhibitors (SSRIs) for anxiety in PD. However, results from uncontrolled studies suggest that SSRIs are effective for anxiety in PD, although in these studies anxiety outcomes were secondary. This review underscores that, given the high prevalence of anxiety disturbances in PD, there is a significant paucity of treatment data for this population. Additional studies are warranted. In the meantime, clinicians should rely on empiric assessments of known risks and putative benefits to guide treatment decisions. Cognitive and behavioral therapies (with or without pharmacotherapy) have demonstrated efficacy and warrant consideration. When feasible, a targeted and individualized multimodal approach utilizing psychotherapeutic interventions along with pharmacologic therapies should be considered.

Depression and Parkinson's disease: current knowledge

Depressive disturbances are common in patients with Parkinson's disease (PD) and influence many other clinical aspects of the disease. In addition to causing inherent emotional distress, depressive disorders negatively impact quality of life, motor and cognitive deficits, functional disability, and other psychiatric comorbidities in patients with PD. Knowledge of the pathophysiology of PD depression remains limited. However, clinical studies demonstrate the efficacy of medications and psychotherapies for PD depression, underscoring the importance of their timely detection and concerted management.

Anxiety and motor fluctuations in Parkinson's disease: a cross-sectional observational study

BACKGROUND

Some studies have suggested a relationship between anxiety and motor fluctuations in patients with Parkinson's disease (PD).

AIM

To describe the nature of the relationship between anxiety symptoms and motor fluctuations and to describe the anxiety symptoms encountered during 'off', 'on' and 'on with dyskinesia' phases.

DESIGN AND METHODS

In this cross-sectional study, 250 patients with idiopathic PD, of whom 118 had motor fluctuations, underwent a standardized clinical assessment including the Unified Parkinson's Disease Rating Scale (UPDRS), the DSM IV criteria for major depression and anxiety disorders, the Hamilton Depression Rating Scale (HAMD), and the Hamilton Anxiety Rating Scale (HARS). In addition, patients with motor fluctuations were administered a questionnaire to assess the presence of anxiety symptoms and their relation to motor states.

RESULTS

Patients with motor fluctuations suffer from generalized anxiety disorder more often than patients without motor fluctuations. When patients with motor fluctuations have anxiety symptoms, the majority report that these have no temporal relationship with specific motor states. When there was a relationship, symptoms were almost always related to 'off' periods. However, a minority of patients experience anxiety symptoms during 'on' or "on with dyskinesia" periods exclusively.

CONCLUSION

Our findings suggest that the relationship between anxiety and motor fluctuations is more complex than can be explained solely by 'wearing off' phenomena of levodopa. Further studies investigating the temporal dynamics of anxiety and motor fluctuations are needed.

A perfusion MRI study of emotional valence and arousal in Parkinson's disease

Background. Brain regions subserving emotion have mostly been studied using functional magnetic resonance imaging (fMRI) during emotion provocation procedures in healthy participants. Objective. To identify neuroanatomical regions associated with spontaneous changes in emotional state over time. Methods. Self-rated emotional valence and arousal scores, and regional cerebral blood flow (rCBF) measured by perfusion MRI, were measured 4 or 8 times spanning at least 2 weeks in each of 21 subjects with Parkinson's disease (PD). A random-effects SPM analysis, corrected for multiple comparisons, identified significant clusters of contiguous voxels in which rCBF varied with valence or arousal. Results. Emotional valence correlated positively with rCBF in several brain regions, including medial globus pallidus, orbital prefrontal cortex (PFC), and white matter near putamen, thalamus, insula, and medial PFC. Valence correlated negatively with rCBF in striatum, subgenual cingulate cortex, ventrolateral PFC, and precuneus—posterior cingulate cortex (PCC). Arousal correlated positively with rCBF in clusters including claustrum-thalamus-ventral striatum and inferior parietal lobule and correlated negatively in clusters including posterior insula—mediodorsal thalamus and midbrain. Conclusion. This study demonstrates that the temporal stability of perfusion MRI allows within-subject investigations of spontaneous fluctuations in mental state, such as mood, over relatively long-time intervals.

Psychometric validation of the revised SCOPA-Diary Card: expanding the measurement of non-motor symptoms in Parkinson's disease

Background

To identify key non-motor symptoms of Parkinson's disease (PD) to include in a daily diary assessment for off-time, revise the Scales for Outcomes of Parkinson's disease Diary Card (SCOPA-DC) to include these non-motor symptoms, and investigate the validity, reliability and predictive utility of the Revised SCOPA-DC in a U.S. population.

Methods

A convenience sample was used to recruit four focus groups of PD patients. Based on findings from focus groups, the SCOPA-DC was revised and administered to a sample of 101 PD patients. Confirmatory factor analysis was conducted to test the domain structure of the Revised SCOPA-DC. The reliability, convergent and discriminant validity, and ability to predict off-time of the Revised SCOPA-DC were then assessed.

Results

Based on input from PD patients, the Revised SCOPA-DC included several format changes and the addition of non-motor symptoms. The Revised SCOPA-DC was best represented by a three-factor structure: Mobility, Physical Functioning and Psychological Functioning. Correlations between the Revised SCOPA-DC and other Health-Related Quality of Life scores were supportive of convergent validity. Known-groups validity analyses indicated that scores on the Revised SCOPA-DC were lower among patients who reported experiencing off-time when compared to those without off-time. The three subscales had satisfactory predictive utility, correctly predicting off-time slightly over two-thirds of the time.

Conclusions

These findings provide evidence of content validity of the Revised SCOPA-DC and suggest that a three-factor structure is an appropriate model that provides reliable and valid scores to assess symptom severity among PD patients with symptom fluctuations in the U.S.

Anxiety and self-perceived health status in Parkinson's disease

Both anxiety and depression are associated with lower self-perceived health status (HS) in persons with Parkinson's disease (PD). Given the high co-morbidity with depression and other non-motor symptoms, it is unclear whether anxiety disorders, in general, versus specific anxiety subtypes have an independent effect on HS in PD. To examine this question, comprehensive assessments of motor and non-motor symptoms from 249 subjects with idiopathic PD followed in three community-based movement disorders neurology practices were analyzed. HS was measured using the 8-item PD Questionnaire (PDQ-8). Psychiatric diagnoses were established by consensus using a panel of six psychiatrists with expertise in geriatric psychiatry and movement disorders. Stepwise multiple regression analyses were used, with the PDQ-8 score as the dependent variable, to identify independent predictors of HS among motor, psychiatric, and other non-motor variables. Among the anxiety disorders, only anxiety associated with motor fluctuations was an independent predictor of HS after accounting for co-morbid depression and other clinical features. In addition, depressive disorders were also an independent predictor of lower HS. Prevention or treatment of state-dependent anxiety may improve HS in persons with PD.

Potential mechanisms underlying anxiety and depression in Parkinson's disease: consequences of l-DOPA treatment

Though the most recognizable symptoms of Parkinson's disease (PD) are motor-related, many patients also suffer from debilitating affective symptoms that deleteriously influence quality of life. Dopamine (DA) loss is likely involved in the onset of depression and anxiety in PD. However, these symptoms are not reliably improved by DA replacement therapy with l-3,4-dihydroxyphenylalanine (l-DOPA). In fact, preclinical and clinical evidence suggests that l-DOPA treatment may worsen affect. Though the neurobiological mechanisms remain unclear, recent research contends that l-DOPA further perturbs the function of the norepinephrine and serotonin systems, already affected by PD pathology, which have been intimately linked to the development and expression of anxiety and depression. As such, this review provides an overview of the clinical characteristics of affective disorders in PD, examines the utility of animal models for the study of anxiety and depression in PD, and finally, discusses potential mechanisms by which DA loss and subsequent l-DOPA therapy influence monoamine function and concomitant affective symptoms.

Pramipexole versus sertraline in the treatment of depression in Parkinson's disease: a national multicenter parallel-group randomized study

In addition to treating the motor symptoms of Parkinson's disease, the dopamine agonist pramipexole has shown an antidepressant effect. The trials, however, included patients with motor complications, raising the question of whether the antidepressant benefit represented only a treatment-related motor improvement. To address this issue, we have conducted a 14-week randomized trial comparing pramipexole with an established antidepressant in patients without motor complications. At seven Italian centers, 67 Parkinsonian outpatients with major depression but no history of motor fluctuations and/or dyskinesia received open-label pramipexole (at 1.5 to 4.5 mg/day) or sertraline (at 50 mg/day). In both groups, the Hamilton Depression Rating Scale (HAM-D) score decreased throughout 12 weeks of treatment, but in the pramipexole group the proportion of patients who recovered, as defined by a final HAM-D score </= 8,was significantly higher, at 60.6% versus 27.3% (p = 0.006). Patients' self-ratings improved in both groups. All adverse events were mild or moderate, but five patients (14.7%) withdrew from the sertraline group. Despite the absence of motor complications, the pramipexole recipients showed improvement on the Unified Parkinson's Disease Rating Scale (UPDRS) motor subscore. We conclude that dopamine agonists may be an alternative to antidepressants in Parkinson's disease.

Factors associated with depression in Parkinson's disease: a cross-sectional study in a Polish population

OBJECTIVE

The aim of this study was to assess the prevalence and factors influencing depression in PD patients in a cross-sectional outpatient clinic - based Polish patients sample.

MATERIALS AND METHODS

One hundred consecutive PD patients were included in this study; 35 of them fulfilled DSM-IV criteria for Major Depression and its severity was assessed with Montgomery-Asberg Depression Rating Scale (MADRS). A structured interview and a neurological examination, including Hoehn and Yahr scale (H-Y), Schwab-England disability scale, II, III, IV parts of Unified Parkinson's Disease Rating Scale (UPDRS), and Mini-Mental State Examination (MMSE) were performed. The parameters obtained were analysed between the depressed and non-depressed PD patients.

RESULTS

The prevalence of depression in PD in Polish population was established at the level of 35%. PD patients with depression scored significantly higher in all UPDRS scales (except for the subscale of clinical fluctuation) and in H-Y scale. PD with depression was also associated with longer PD duration, higher doses of L-dopa equivalents, patients' age, general impairment of daily living in Schwab and England disability scale, lower MMSE and higher clinical fluctuations. However, those six differences were insignificant.

CONCLUSIONS

Depression prevalence rate among PD patients in Polish population is slightly lower than in most of other published studies. This may result from strict selection criteria, use of specific outcome measures and restricted criteria for depression that were applied.

Levodopa challenge neuroimaging of levodopa-related mood fluctuations in Parkinson's disease

Some patients with advanced Parkinson's disease (PD) develop dose-related fluctuations in mood. This may reflect alterations in dopamine-influenced brain circuits that mediate emotion. However, there is no available information to localize which dopamine-influenced neurons may be most affected. Eight patients with PD and clinically significant levodopa-related mood fluctuations (mania, depression, or anxiety) were compared to 13 patients with similarly severe PD and fluctuations of motor function but not of mood. Regional cerebral blood flow (rCBF) was measured with positron emission tomography before and after levodopa (in the presence of carbidopa). The rCBF response to levodopa in medial frontal gyrus and posterior cingulate cortex (PCC) significantly differed between mood fluctuators and control patients (corrected p<0.02). Other regions with uncorrected p<0.001 in this comparison were cortical Brodmann areas 22, 40, 13, 11, and 28, hippocampus, and claustrum. The levodopa activation paradigm detected group differences not evident in a comparison of resting rCBF. Abnormalities of dopamine innervation may produce mood fluctuations via effects on PCC, an area strongly linked to mood and anxiety and with known rCBF responsiveness to levodopa or D2-like dopamine receptor agonists. We speculate that mood fluctuations may arise in parkinsonian patients who have abnormal dopaminergic modulation of caudate nucleus, anterior cingulate cortex, or orbital frontal cortex, all of which innervate PCC. The findings require confirmation in larger and better-matched groups.

Prevalence, etiology, and treatment of depression in Parkinson's disease

Parkinson's disease (PD) is primarily a disease of elderly individuals with a peak age at onset of 55 to 66 years. It is characterized by bradykinesia, rigidity, tremor, and postural instability; and affects approximately 1 million individuals in the US and is the second most common neurodegenerative disease next to Alzheimer's disease. The motor symptoms of PD are the focus of pharmacotherapy, yet the nonmotor symptoms (e.g., dementia, psychosis, anxiety, insomnia, autonomic dysfunction, and mood disturbances) can be the most disturbing, disabling, and misunderstood aspects of the disease. Depressive symptoms occur in approximately half of PD patients and are a significant cause of functional impairment for PD patients. There is accumulating evidence suggesting that depression in PD is secondary to the underlying neuroanatomical degeneration, rather than simply a reaction to the psychosocial stress and disability. The incidence of depression is correlated with changes in central serotonergic function and neurodegeneration of specific cortical and subcortical pathways. Understanding comorbid depression in PD may therefore add to the understanding of the neuroanatomical basis of melancholia.

A possible substrate for dopamine-related changes in mood and behavior: prefrontal and limbic effects of a D3-preferring dopamine agonist

Dopamine can induce fascinating, complex human behavioral states, including disinhibition, euphoria, or elaborate stereotypies, whereas dopamine deficiency can cause anxiety or sadness. Limited data suggest that these phenomena may involve dysfunction of orbital frontal cortex, cingulate cortex, or ventral striatum. The dopamine D3 receptor (D3R) has an anatomic distribution that suggests it could mediate these effects, but almost no data directly demonstrate the regional functional effects of D3R activation. We used quantitative positron emission tomography (PET), [15O]water, and the D3-preferring dopamine agonist pramipexole to identify D3-mediated regional cerebral blood flow (rCBF) responses in living primates. We studied seven normal baboons ventilated with 70% nitrous oxide, and analyzed results voxelwise in a common atlas space. At clinically relevant doses, pramipexole produced statistically robust decreases in rCBF in bilateral orbitofrontal cortex, thalamus, operculum, posterior and anterior (subgenual) cingulate cortex, and insula (in decreasing order of significance). Cortical areas related to movement were relatively unaffected, and rCBF did not change in cerebellum or visual cortex. The dose-response curve and duration of pramipexole's effects suggest that these rCBF responses indicate functional effects of a D3-preferring agonist. A D2-preferring agonist studied under the same conditions produced a quantitatively different pattern of responses. We conclude that a dopamine D3 receptor agonist preferentially affects brain activity in prefrontal and limbic cortex, and speculate that dopamine's effects on these regions via D3Rs may mediate some of the known psychiatric complications of dopamine deficiency or excess.