Are selective serotonin reuptake inhibitors associated with greater apathy in Parkinson's disease?

Shared and distinct cortical morphometric alterations in five neuropsychiatric symptoms of Parkinson's disease

Neuropsychiatric symptoms (including anxiety, depression, apathy, impulse-compulsive behaviors and hallucinations) are among the most common non-motor features of Parkinson's disease. Whether these symptoms should be considered as a direct consequence of the pathophysiologic mechanisms of Parkinson's disease is controversial. Morphometric similarity network analysis and epicenter mapping approach were performed on T1-weighted images of 505 patients with Parkinson's disease and 167 age- and sex-matched healthy participants from Parkinson's Progression Markers Initiative database to reveal the commonalities and specificities of distinct neuropsychiatric symptoms. Abnormal cortical co-alteration pattern in patients with neuropsychiatric symptoms was in somatomotor, vision and frontoparietal regions, with epicenters in somatomotor regions. Apathy, impulse-compulsive behaviors and hallucinations shares structural abnormalities in somatomotor and vision regions, with epicenters in somatomotor regions. In contrast, the cortical abnormalities and epicenters of anxiety and depression were prominent in the default mode network regions. By embedding each symptom within their co-alteration space, we observed a cluster composed of apathy, impulse-compulsive behaviors and hallucinations, while anxiety and depression remained separate. Our findings indicate different structural mechanisms underlie the occurrence and progression of different neuropsychiatric symptoms. Based upon these results, we propose that apathy, impulse-compulsive behaviors and hallucinations are directly related to damage of motor circuit, while anxiety and depression may be the combination effects of primary pathophysiology of Parkinson's disease and psychosocial causes.

Selective Serotonin Reuptake Inhibitors for the Treatment of Depression in Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Although selective serotonin reuptake inhibitors (SSRIs) are usually considered safe to use in patients with Parkinson's disease (PD), there are mixed data about their effectiveness, and only a few investigations have led to a total improvement of depressive symptoms in patients with PD.

OBJECTIVES

We aimed to conduct a comprehensive systematic review and meta-analysis of all studies that investigated the effectiveness of SSRIs in treating depression in the context of PD.

METHODS

From its commencement to June 2024, the databases of MEDLINE via PubMed, Scopus, Embase, and Google Scholar were electronically searched for the relevant papers. All full-text journal articles assessing the effectiveness of SSRIs in treating depression in patients with PD were included. The tool developed by the Cochrane Collaboration was utilized to evaluate the bias risk. Data were analyzed utilizing a pair-wise comparison meta-analysis using the standardized mean difference.

RESULTS

A total of 19 articles and 22 separate interventions were included. We found that SSRI treatment attenuated depression in patients with PD (1.242 standardized mean difference, 95% confidence interval 0.956, 1.529, p < 0.001). The general heterogeneity of the studies was medium (ϰ2 = 72.818, T2 = 0.317, df = 21, I2 = 71.15%, p < 0.001). The funnel plot was reasonably symmetrical. However, three studies were trimmed to the left of the mean. Begg's test (p = 0.080), Egger's test (p = 0.121), and funnel plot showed no significant risk of publication bias. The meta-regression showed that the treatment effect increased as a function of paroxetine treatment duration (slope p = 0.001) but decreased as a function of sertraline treatment duration (slope p = 0.019).

CONCLUSIONS

There are few controlled antidepressant trials on the PD population, even though patients with PD frequently experience depression and use antidepressants. Clinical studies that are larger and better structured are needed in the future to determine if antidepressants are useful for treating patients with PD with depression.

Greater Apathy Associated With Selective Serotonin Reuptake Inhibitor Use in Parkinson's Disease

OBJECTIVE

Apathy, a motivational disorder, is common in Parkinson's disease (PD) and often misdiagnosed as depression. Use of selective serotonin reuptake inhibitors (SSRIs) has been associated with increased apathy in adolescents and adults with depression. Based on observations that serotonin may downregulate dopaminergic systems, we examined the relationship between apathy and SSRI use in individuals with PD.

METHODS

Medications, mood/motivation scales, and clinical data were collected from a convenience sample of 400 individuals with PD. Depression and apathy were measured using the Beck Depression Inventory-II (BDI-Il) and the Apathy Scale (AS). Antidepressant medications were grouped by mechanism type.

RESULTS

Of the 400 PD patients, 26% were on SSRIs. On standard mood/motivation scales, 38% of the sample exceeded clinical cut-offs for apathy and 28% for depression. Results of hierarchical regression analyses revealed that SSRIs were the only antidepressant that were significantly associated with higher apathy scores (β = .1, P = .02). Less education (β = -.1, P = .01) worse cognition (β = -.1, P = .01), and greater depressive symptoms (β = .5, P < .001) were also significant predictors of apathy.

CONCLUSION

These findings suggest that use of SSRIs, but not other antidepressants, is associated with greater apathy in PD. Given the interactive relationship between serotonin and dopamine, the current findings highlight the importance of considering apathy when determining which antidepressants to prescribe to individuals with PD. Similarly, switching a SSRI for an alternative antidepressant in individuals with PD who are apathetic may be a potential treatment for apathy that needs further study.

Serotonin as a biomarker of toxin-induced Parkinsonism

BACKGROUND

Loss of dopaminergic neurons underlies the motor symptoms of Parkinson's disease (PD). However stereotypical PD symptoms only manifest after approximately 80% of dopamine neurons have died making dopamine-related motor phenotypes unreliable markers of the earlier stages of the disease. There are other non-motor symptoms, such as depression, that may present decades before motor symptoms.

METHODS

Because serotonin is implicated in depression, here we use niche, fast electrochemistry paired with mathematical modelling and machine learning to, for the first time, robustly evaluate serotonin neurochemistry in vivo in real time in a toxicological model of Parkinsonism, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

RESULTS

Mice treated with acute MPTP had lower concentrations of in vivo, evoked and ambient serotonin in the hippocampus, consistent with the clinical comorbidity of depression with PD. These mice did not chemically respond to SSRI, as strongly as control animals did, following the clinical literature showing that antidepressant success during PD is highly variable. Following L-DOPA administration, using a novel machine learning analysis tool, we observed a dynamic shift from evoked serotonin release in the hippocampus to dopamine release. We hypothesize that this finding shows, in real time, that serotonergic neurons uptake L-DOPA and produce dopamine at the expense of serotonin, supporting the significant clinical correlation between L-DOPA and depression. Finally, we found that this post L-DOPA dopamine release was less regulated, staying in the synapse for longer. This finding is perhaps due to lack of autoreceptor control and may provide a ground from which to study L-DOPA induced dyskinesia.

CONCLUSIONS

These results validate key prior hypotheses about the roles of serotonin during PD and open an avenue to study to potentially improve therapeutics for levodopa-induced dyskinesia and depression.

Apathy and Motivation: Biological Basis and Drug Treatment

Apathy is a disabling syndrome associated with poor functional outcomes that is common across a broad range of neurological and psychiatric conditions. Currently, there are no established therapies specifically for the condition, and safe and effective treatments are urgently needed. Advances in the understanding of motivation and goal-directed behavior in humans and animals have shed light on the cognitive and neurobiological mechanisms contributing to apathy, providing an important foundation for the development of new treatments. Here, we review the cognitive components, neural circuitry, and pharmacology of apathy and motivation, highlighting converging evidence of shared transdiagnostic mechanisms. Though no pharmacological treatments have yet been licensed, we summarize trials of existing and novel compounds to date, identifying several promising candidates for clinical use and avenues of future drug development.

Investigating affective neuropsychiatric symptoms in rodent models of Parkinson's disease

Affective neuropsychiatric disorders such as depression, anxiety and apathy are among the most frequent non-motor symptoms observed in people with Parkinson's disease (PD). These conditions often emerge during the prodromal phase of the disease and are generally considered to result from neurodegenerative processes in meso-corticolimbic structures, occurring in parallel to the loss of nigrostriatal dopaminergic neurons. Depression, anxiety, and apathy are often treated with conventional medications, including selective serotonin reuptake inhibitors, tricyclic antidepressants, and dopaminergic agonists. The ability of these pharmacological interventions to consistently counteract such neuropsychiatric symptoms in PD is still relatively limited and the development of reliable experimental models represents an important tool to identify more effective treatments. This chapter provides information on rodent models of PD utilized to study these affective neuropsychiatric symptoms. Neurotoxin-based and genetic models are discussed, together with the main behavioral tests utilized to identify depression- and anxiety-like behaviors, anhedonia, and apathy. The ability of various therapeutic approaches to counteract the symptoms observed in the various models is also reviewed.

Apathy in Parkinson's Disease: Clinical Patterns and Neurobiological Basis

Apathy is commonly defined as a loss of motivation leading to a reduction in goal-directed behaviors. This multidimensional syndrome, which includes cognitive, emotional and behavioral components, is one of the most prevalent neuropsychiatric features of Parkinson's disease (PD). It has been established that the prevalence of apathy increases as PD progresses. However, the pathophysiology and anatomic substrate of this syndrome remain unclear. Apathy seems to be underpinned by impaired anatomical structures that link the prefrontal cortex with the limbic system. It can be encountered in the prodromal stage of the disease and in fluctuating PD patients receiving bilateral chronic subthalamic nucleus stimulation. In these stages, apathy may be considered as a disorder of motivation that embodies amotivational behavioral syndrome, is underpinned by combined dopaminergic and serotonergic denervation and is dopa-responsive. In contrast, in advanced PD patients, apathy may be considered as cognitive apathy that announces cognitive decline and PD dementia, is underpinned by diffuse neurotransmitter system dysfunction and Lewy pathology spreading and is no longer dopa-responsive. In this review, we discuss the clinical patterns of apathy and their treatment, the neurobiological basis of apathy, the potential role of the anatomical structures involved and the pathways in motivational and cognitive apathy.

Depression in Major Neurodegenerative Diseases and Strokes: A Critical Review of Similarities and Differences among Neurological Disorders

Depression and anxiety are highly prevalent in most neurological disorders and can have a major impact on the patient's disability and quality of life. However, mostly due to the heterogeneity of symptoms and the complexity of the underlying comorbidities, depression can be difficult to diagnose, resulting in limited recognition and in undertreatment. The early detection and treatment of depression simultaneously with the neurological disorder is key to avoiding deterioration and further disability. Although the neurologist should be able to identify and treat depression initially, a neuropsychiatry team should be available for severe cases and those who are unresponsive to treatment. Neurologists should be also aware that in neurodegenerative diseases, such as Alzheimer's or Parkinson's, different depression symptoms could develop at different stages of the disease. The treatment options for depression in neurological diseases include drugs, cognitive-behavioral therapy, and somatic interventions, among others, but often, the evidence-based efficacy is limited and the results are highly variable. Here, we review recent research on the diagnosis and treatment of depression in the context of Alzheimer's disease, Parkinson's disease, and strokes, with the aim of identifying common approaches and solutions for its initial management by the neurologist.

Changes in Apathy, Depression, and Anxiety in Parkinson's Disease from before to during the COVID-19 Era

Apathy, depression, and anxiety are common non-motor symptoms of Parkinson's disease (PD). Tracking the changes in such symptoms over time would be valuable not only to determine their natural course during the disease, but also to establish the effects of unusual historical events interacting with the natural course. Having collected data on apathy (Apathy Scale), depression (Beck Depression Inventory-II), and anxiety (Parkinson's Anxiety Scale) in a large sample of persons with PD (PwPD) before the beginning of the COVID-19 era, we followed up with these individuals to investigate the changes in their prevalence of apathy, depression, and anxiety across two timepoints (T1 and T2). Of the original 347 participants, 111 responded and provided complete data at T2. The data collection at T1, before COVID-19, occurred between 2017-2018. The data collection at T2 occurred in 2021 and included the same measures, with the addition of the Coronavirus Impact Scale to assess the effects of the pandemic on the individual participants. Over this period, there was a significant increase in apathy, but not in depression or anxiety. Anxiety and depression, but not apathy, were correlated with the impact of COVID-19.

Apathy in Parkinson's Disease: Defining the Park Apathy Subtype

Apathy is a neurobehavioural symptom affecting Parkinson's disease patients of all disease stages. Apathy seems to be associated with a specific underlying non-motor disease subtype and reflects dysfunction of separate neural networks with distinct neurotransmitter systems. Due to the complicated neuropsychiatric aetiology of apathy, clinical assessment of this invalidating non-motor symptom remains challenging. We aim to summarize the current findings on apathy in Parkinson's disease and highlight knowledge gaps. We will discuss the prevalence rates across the different disease stages and suggest screening tools for clinically relevant apathetic symptoms. We will approach the fundamental knowledge on the neural networks implicated in apathy in a practical manner and formulate recommendations on patient-tailored treatment. We will discuss the Park apathy phenotype in detail, shedding light on different clinical manifestations and implications for prognosis. With this review, we strive to distil the vast available theoretical knowledge into a clinical and patient-oriented perspective.

Depression: why drugs and electricity are not the answer

The dominant view within mental health services and research suggests that feeling depressed is a kind of medical illness, partially caused by various biological deficits which are somehow corrected by physical interventions. This article critically appraises evidence for the effectiveness and value of antidepressant drugs and electroconvulsive therapy (ECT), the two principle physical treatments recommended for depression. It also describes the negative effects of these interventions and raises concerns about how they impact the brain. We propose an alternative understanding that recognises depression as an emotional and meaningful response to unwanted life events and circumstances. This perspective demands that we address the social conditions that make depression likely and suggests that a combination of politics and common sense needs to guide us in providing help for one another when we are suffering in this way. This alternative view is increasingly endorsed around the world, including by the United Nations, the World Health Organization and service users who have suffered negative consequences of physical treatments that modify brain functions in ways that are not well-understood.

Comparative efficacy and acceptability of drug treatments for Parkinson's disease with depression: A systematic review with network meta-analysis

Depressive symptom is the prevailing non-motor symptom of Parkinson's disease (PD). Drug treatments for depressed PD (dPD) can mitigate the symptoms of patients. However, the results are discordant and need further analysis. This systematic review with network meta-analysis aims to evaluate the drug treatments for dPD. We included double-blind, randomized controlled trials to compare antidepressants with placebo or other antidepressants in dPD. We performed traditional pairwise analysis and network meta-analysis concerning the efficacy, acceptability, depression score, and adverse effect. The surface under the cumulative ranking curve was to assess the ranking probabilities of the enrolled agents. We enrolled 62 studies, including 12,353 subjects, to analyze these estimates. For the traditional pairwise meta-analysis, dopamine agonist (DOP; OR = 2.20 [95% CI, 1.46 to 3.33]) and selective serotonin reuptake inhibitor (SSRI; OR = 2.30 [95% CI, 1.15 to 4.60]) were observed to improve the efficacy compared with placebo. For network meta-analysis, DOP was observed to improve the efficacy compared with placebo (OR = -0.84 [95% CI, -1.20 to -0.48]). Both direct and indirect evidence showed that several treatments, e.g., DOP, monoamine-oxidase inhibitor, serotonin-norepinephrine reuptake inhibitors, SSRI, and tricyclic antidepressants, significantly improved depressive symptoms. DOP and SSRI had good efficacy and improved symptoms considerably in dPD, but the adverse effect of these agents was needed to follow closely.

A Systematic Review of Apathy and Depression in Progressive Supranuclear Palsy

Depression and apathy can be significant problems in progressive supranuclear palsy (PSP). Using PRISMA guidelines, this systematic review examined prevalence estimates for depression and apathy in PSP, and, how different methods of definition may influence results. 29 studies meeting inclusion/exclusion criteria were identified: 12 on depression, 9 on apathy, and 8 on both. Studies were stratified according to whether a diagnostic criteria, rating scale or screening question methodology was employed. The weighted mean prevalence was 59.7% for depression (sample size = 473) and 58.3% for apathy (sample size = 858). Results for depression using diagnostic criteria or rating scales were similar whereas screening questions were associated with considerable inconsistency. Depression prevalence appeared to be influenced by apathy but not somatic symptoms. Most apathy studies relied only on a screening question method. Depression and apathy are common in PSP but there is a need for consensus on how they are defined (both tools and cut-off scores). In particular, more studies probing apathy in greater detail than a simple screening question are required.

Ninjin'yoeito, a traditional Japanese medicine, increases dopamine content in PC12 cells

Dementia is exacerbated by loss of appetite and amotivation, and recent studies have indicated that ninjin'yoeito improves anorexia and amotivation. Previous studies suggest that ninjin'yoeito inhibits dopamine-metabolizing enzymes and enhances dopamine signaling. However, whether ninjin'yoeito increases dopamine content in living cells remains unclear. Here, PC12 cells were used to examine whether ninjin'yoeito affects the dopamine metabolic pathway. Dopamine content significantly increased 3 h after treatment ninjin'yoeito extract. Concomitantly, the levels of 3-methoxytyramine and 3,4-dihydroxyphenylacetic acid were significantly reduced. The effects of components of ninjin'yoeito on the dopamine metabolic pathway were also assessed. Treatment with onjisaponin B, nobiletin, and schisandrin, and the ingredients of Polygalae Radix, Citri Unshiu Pericarpium, and Schisandrae Fructus increased dopamine content and decreased its metabolite content in the culture media. Our findings suggest that ninjin'yoeito improves anorexia and amotivation by inhibiting metabolic enzyme and increasing the dopamine content in cells.

Revisiting Apathy in Alzheimer's Disease: From Conceptualization to Therapeutic Approaches

Apathy is a neurobehavioral syndrome characterized by impaired motivation for goal-directed behaviors and cognitive activity, alongside blunted affect. Apathy is a common neuropsychiatric syndrome in Alzheimer's disease (AD), with a 5-year prevalence over 70%. Apathy also serves as a prognostic indicator, correlating with the progression of AD. Despite advances in its conceptualization and understanding of its neural basis, there is very limited empirical evidence to support the available strategies for the treatment of apathy in AD. Given its complex pathophysiology, including distinct substrates for different apathy dimensions (affective, cognitive, and behavioral), it is unlikely that a single pharmacological or nonpharmacological strategy will be effective for all cases of apathy in AD. High-quality evidence research is needed to better understand the role of specific strategies aiming at a personalized approach.

Vortioxetine Improved Depressive State In Parkinson's Disease

We report the case of a 67-year-old Japanese Parkinson's disease (PD) patient with depression who was successfully treated with vortioxetine. The patient's PD was being treated with levodopa (100 mg/day). As improvement was noted in PD symptoms, levodopa was continued. Subsequently, she was referred to our department due to worsening of her depressive symptoms, including depressed mood, anhedonia, decreased energy, decreased concentration, decreased motivation, insomnia, hopelessness, and worthlessness. The patient did not respond to paroxetine and escitalopram. Finally, vortioxetine improved her depressive state without worsening PD.

Apathy: Neurobiology, Assessment and Treatment

Apathy is a highly prevalent, disabling and treatment resistant syndrome. It is defined as a quantitative reduction of goal- directed activity in comparison to the patient’s previous level of in multiple dimensions including behavior/cognition, emotion and social interaction. It has been described in major depressive disorder, Alzheimer’s disease, frontotemporal dementia, Parkinson’s Disease, cerebrovascular disease, and vascular dementia, among others. This review will address the neuropsychology and associated neurobiological underpinnings of apathy in the above conditions, identify specific methods to assess apathy clinically, and review the literature on managing apathy across these various disorders.

The use of vortioxetine for depression in patients with Parkinson's disease in the early and advanced stages of the disease

Depression is one of the most common non-motor manifestations of Parkinson's disease (PD), which largely determines both the severity of the course of the disease and the life expectancy of patients, as well as the compliance of patients to and the efficiency of antiparkinsonian therapy. In this connection, the search for a safe and effective antidepressant for patients with PD is of particular relevance.

Objective: to evaluate the efficacy and safety of vortioxetine in patients with PD complicated by mild to moderate depression.

Patients and methods. Examinations were made in 150 patients with PD in its early and advanced stages (Hoehn-Yahr stages: 1.0 to 3.0). All the patients were treated with vortioxetine at a dose of 15 or 20 mg/day for 8 months. The investigators used clinical and psychopathological rating scales, such as the Hospital Depression Scale (HADS-D), the Hospital Anxiety Scale (HADS-A), the Beck Depression Inventory (BDI), and the Montgomery-Asberg Depression Rating Scale (MADRS). The severity of PD motor manifestations was assessed according to the Unified PD Rating Scale (UPDRS) Part III.

Results and discussion. During the follow-up period corresponding to 12 weeks of vortioxetine use, all the patients showed a significant decrease in MARDS, HADS-A and HADS-D, and BDI scores for depression and anxiety (p < 0.001). Vortioxetine demonstrated an optimal balance between tolerability and clinical efficacy in correcting affective disorders in this patient group. In addition, analysis of the dynamics of motor disorders yielded data on the improvement of movement functions while correcting depression as lower UPDRS Part III total scores (p < 0.001).

Conclusion. The findings suggest that vortioxetine has a significant effect on depression and anxiety in patients with PD in its early and advanced stages, good tolerability, and a rapid-onset effect.

Diagnosis, treatment and management of apathy in Parkinson's disease: a scoping review

OBJECTIVE

To conduct a scoping review of the literature on apathy in Parkinson's disease (PD), to better understand how apathy in Parkinson's disease is diagnosed, treated and managed.

METHODS

MEDLINE, Embase, PsycINFO, CINAHL, Cochrane Central Register of Control Trials and Cochrane Database of Systematic Reviews were searched to 17 May 2017. An updated review was run from 17 May 2017 to 28 January 2019. The grey literature was searched using the CADTH Grey Matters tool. Original peer-reviewed research was included if it included individuals with PD and apathy. Non-original data was only included if it was in the form of meta-analysis. All information regarding diagnosis, treatment and management of PD was extracted. Citation screening and extraction were performed in duplicate.

RESULTS

From 11 375 citations, 362 articles were included in the final review. The majority of included studies focussed on prevalence, with few studies examining treatment. Twenty screening tools for apathy were identified. Fifty per cent of treatment studies were randomised control trials (RCTs). RCTs applied treatment methods including: exercise, mindfulness, rotigotine (Neupro) transdermal patch and rivastigmine (Exelon).

CONCLUSIONS

This review identified a large body of literature describing current knowledge on diagnosing, treating and managing apathy in PD. Future research should aim to detect an ideal screening tool for apathy in PD, to identify the best treatment options for apathy and the variety of comorbidities it may present with and finally aim to better understand postoperative apathy in those with deep brain stimulation.

Selective serotonin reuptake inhibitors-associated apathy syndrome: A cross sectional study

Selective serotonin reuptake inhibitors (SSRIs), commonly used to treat depression, are associated with loss of motivation, anergy, and lack of curiosity often referred collectively as apathy. However, this association has not been systematically assessed using a specific rating scale for measuring apathy syndrome. Our objective was to study the association between SSRI use and apathy syndrome.We conducted a retrospective chart review of 125 patients enrolled in an outpatient psychiatry clinic. The prevalence of apathy syndrome and its clinical significance (based on standardized assessment) were compared between patients treated and not treated with SSRIs. Apathy was assessed using the Apathy Evaluation Scale-clinician version with a score ranging 18-72 with higher score for worse apathy. A score of greater than 30 is considered clinically significant apathy.Among 119 patients, the mean apathy scores were significantly higher in those treated with SSRIs compared to those not treated with SSRIs (42.5 ± 9.2 vs 31.3 ± 6, P < .0001). The SSRI group also had a significantly higher percentage of patients with clinically significant apathy (92% vs 61%, P < .0001). Use of all SSRIs was associated with the presence of apathy. Apathy was seen in all mental health diagnostic categories with highest Apathy evaluation scale-clinician version scores in those with dementia.SSRI use may be associated with higher rates of apathy syndrome. Clinicians should specifically inquire about iatrogenic apathy syndrome when evaluating patients on an SSRI if there is suspicion of loss of motivation. Limitations of this study included retrospective nature of this study, and that majority of the sample was males. Prospective studies are needed to elucidate information regarding the prevalence, etiology, and treatment response for SSRI-associated apathy syndrome.

Neuropsychiatric aspects of Parkinson disease psychopharmacology: Insights from circuit dynamics

Parkinson disease (PD) is a neurodegenerative disorder with a complex pathophysiology characterized by the progressive loss of dopaminergic neurons within the substantia nigra. Persons with PD experience several motoric and neuropsychiatric symptoms. Neuropsychiatric features of PD include depression, anxiety, psychosis, impulse control disorders, and apathy. In this chapter, we will utilize the National Institutes of Mental Health Research Domain Criteria (RDoC) to frame and integrate observations from two prevailing disease constructions: neurotransmitter anomalies and circuit physiology. When there is available evidence, we posit how unified translational observations may have clinical relevance and postulate importance outside of PD. Finally, we review the limited evidence available for pharmacologic management of these symptoms.

Pathogenesis, clinical features, and treatments of depression in Parkinson's disease

Depression is the most common non-motor manifestation of Parkinson's disease (PD), which significantly affects the rate of disease progression and increases the risk of motor complications and dementia. The paper considers the etiology and pathogenesis, cause-and-effect factors of depression in PD, and features of its diagnosis and treatment. Attention is paid to the algorithm for a physician's actions in the detection of depressive disorder in a patient with PD, to the choice of an antidepressant, and to the promising areas of therapy.

[The efficacy of pharmacological approaches to therapy of the apathy syndrome in dementia disorders (the review)]

The article presents a literature review of psychopharmacological methods of treatment of the apathy syndrome, which is common in neurocognitive disorders. The review provides recommendations for the management of such patients, taking into account evidence-based medicine.

Current treatment of behavioral and cognitive symptoms of Parkinson's disease

Cognitive and behavioral symptoms are common in Parkinson's disease, may occur even in the prodromal stages of the disease, worsen with disease progression, and surpass motor symptoms as the major factors affecting patient quality of life and caregiver burden. The symptoms may be caused by the disease pathology or they may represent adverse effects of treatment, or both etiological factors may contribute. Although many of these symptoms are related to dopaminergic dysfunction or dopaminergic medication, other neurotransmitters are involved as well. Behavioral symptoms including impulse control disorders, apathy, psychosis, as well as mild cognitive impairment and dementia are reviewed with a special focus on current treatment approaches.

Antidepressants for Depression, Apathy, and Gait Instability in Parkinson's Disease: A Multicenter Randomized Study

Objective Depression, apathy, and gait instability are cardinal symptoms in patients with Parkinson's disease (PD). Selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are used for treating the psychiatric symptoms of PD. This is the first prospective randomized study to compare the efficacy of an SNRI (duloxetine) with SSRIs (paroxetine, escitalopram) in improving depressive symptoms and apathy (primary) and freezing of gait (FOG; secondary) in patients with PD. Methods In this prospective, multicenter, open-label, randomized study, Japanese PD patients with a Quick Inventory of Depressive Symptomatology-Japanese (QIDS-J) score ≥6 were randomly assigned to receive an SSRI (27 enrolled, 25 analyzed) or duloxetine (28 enrolled, 27 analyzed) and were assessed at 6 and 10 weeks. Results The mean change (SD) in the QIDS J [SSRI -2.4 (3.6), p=0.015; SNRI -2.3 (3.9), p=0.029] and FOG-Questionnaire [SSRI -2.9 (4.2), p=0.012; SNRI -3.4 (4.7), p=0.010] scores (from baseline) at 10 weeks was statistically significant, while the mean change in the Apathy Scale scores was not [SSRI -2.7 (5.4), p=0.054; SNRI -1.5 (3.7), p=0.109]. No significant differences were observed between the SSRI and SNRI groups. The treatments were well-tolerated; however, gastrointestinal events were more common with SSRIs. Two SNRI-treated patients reported an exacerbation of tremor. Conclusion SSRIs and SNRIs improve the depressive symptoms and FOG in PD patients with mild to severe depressive symptoms. However, their effectiveness in treating apathy remains to be elucidated.

Palliative medicine and end-of-life care

Palliative care is an approach to the care of patients, affected by serious illness, and their families that aims to reduce suffering through the management of medical symptoms, psychosocial issues, spiritual well-being, and setting goals of care. Patients and families affected by a neurodegenerative illness have significant palliative care needs beginning at the time of diagnosis and extending through end-of-life care and bereavement. We advocate an approach to addressing these needs where the patient's primary care provider or neurologist plays a central role. Key skills in providing effective palliative care to this population include providing the diagnosis with compassion, setting goals of care, anticipating safety concerns, caregiver assessment, advance care planning, addressing psychosocial concerns, and timely referral to a hospice. Managing distressing medical and psychiatric symptoms is critical to improving quality of life throughout the disease course as well as at end-of-life. Many symptoms are common across illnesses; however, there are issues that are specific to the most common classes of neurodegenerative illness, namely dementia, parkinsonism, and motor neuron disease. Incorporating a palliative approach to care, although challenging in many ways, empowers physicians to provide greater support and guidance to patients and families in making the difficult journey through a neurodegenerative illness.

Interactions of the tricyclic antidepressant drug amitriptyline with L-DOPA in the striatum and substantia nigra of unilaterally 6-OHDA-lesioned rats. Relevance to motor dysfunction in Parkinson's disease

Antidepressant drugs are recommended for the treatment of Parkinson's disease (PD)-associated depression but their role in the modulation of L-DOPA-induced behavioral and neurochemical markers is poorly explored. The aim of the present study was to examine the impact of the tricyclic antidepressant amitriptyline and L-DOPA, administered chronically alone or in combination, on rotational behavior, monoamine levels and binding of radioligands to their transporters in the dopaminergic brain structures of unilaterally 6-OHDA-lesioned rats. Binding of [³H]nisoxetine to noradrenaline transporter (NET), [³H]GBR 12,935 to dopamine transporter (DAT) and [³H]citalopram to serotonin transporter (SERT) were analyzed by autoradiography. Amitriptyline administered alone did not induce rotational behavior but in combination with L-DOPA increased the number of contralateral rotations much more strongly than L-DOPA alone. The combined treatment also significantly increased the tissue dopamine (DA) content in the ipsilateral striatum and substantia nigra (SN) vs. L-DOPA alone. 6-OHDA-mediated lesion of nigrostriatal DA neurons drastically reduced DAT and NET bindings in the ipsilateral striatum. In the ipsilateral SN, DAT binding decreased while NET binding rose. SERT binding increased significantly mainly in the SN. Amitriptyline administered alone or jointly with L-DOPA had no effect on DAT binding on the lesioned side, significantly decreased SERT binding in the striatum and SN while NET binding only in the SN. Since in the DA-denervated striatum, SERT is mainly responsible for reuptake of L-DOPA-derived DA while in the SN, SERT and NET are involved, the inhibition of these transporters by antidepressant drugs may improve dopaminergic transmission and consequently motor behavior.

Assessment and Management of Neuropsychiatric Symptoms in Parkinson's Disease

Neuropsychiatric symptoms are highly prevalent in Parkinson's disease and associated with decreased quality of life and adverse health outcomes. In this review, the assessment and management of common neuropsychiatric symptoms are discussed: depression, anxiety, psychosis, cognitive impairment, dementia and apathy. Validated assessment scales are now available for the majority of symptoms. Balancing dopaminergic therapy plays an important role in their management as increasing doses of dopaminergic agents might address depression and anxiety related to 'off' phases, non-motor fluctuations and apathy, while dose reduction might alleviate psychotic symptoms. More targeted treatment is possible through medications utilising different pathways. Although efficacy profiles of individual agents require further exploration, antidepressants as a drug class have shown utility in depression and anxiety in Parkinson's disease. Psychological therapies, especially cognitive behavioural approaches, are effective. Pimavanserin allows the treatment of psychosis in Parkinson's disease without directly affecting the dopaminergic and cholinergic system. The cholinergic system is currently the only target in Parkinson's disease dementia, and antagonists of this system, as are many psychotropic drugs, need to be used with caution. Management of apathy largely relies on non-pharmacological strategies adapted from dementia care, with antidepressants being ineffective and the role of stimulant therapy needing further evaluation.

Efficacy of antidepressive medication for depression in Parkinson disease: a network meta-analysis

BACKGROUND

Parkinson disease (PD) was considered as the 2nd most prevalent neurodegenerative disorder after Alzheimer disease, while depression is a prevailing nonmotor symptom of PD. Typically used antidepression medication includes tricyclic antidepressants (TCA), selective serotonin reuptake inhibitors (SSRI), serotonin and norepinephrine reuptake inhibitors (SNRI), monoamine-oxidase inhibitors (MAOI), and dopamine agonists (DA). Our study aimed at evaluating the efficacy of antidepressive medications for depression of PD.

METHODS

Web of Science, PubMed, Embase, and the Cochrane library were searched for related articles. Traditional meta-analysis and network meta-analysis (NMA) were performed with outcomes including depression score, UPDRS-II, UPDRS-III, and adverse effects. Surface under the cumulative ranking curve (SUCRA) was also performed to illustrate the rank probabilities of different medications on various outcomes. The consistency of direct and indirect evidence was also assessed by node-splitting method.

RESULTS

Results of traditional pairwise meta-analysis were performed. Concerning depression score, significant improvement was observed in AD, MAOI, SSRI, and SNRI compared with placebo. NMA was performed and more information could be obtained. DA was illustrated to be effective over placebo concerning UPDRS-III, MAOI, and SNRI. DA demonstrated a better prognosis in UPDRS-II scores compared with placebo and MAOI. However, DA and SSRI demonstrated a significant increase in adverse effects compared with placebo. The SUCRA value was calculated to evaluate the ranking probabilities of all medications on investigated outcomes, and the consistency between direct and indirect evidences was assessed by node-splitting method.

CONCLUSION

SSRI had a satisfying efficacy for the depression of PD patients and could improve activities of daily living and motor function of patient but the adverse effects are unneglectable. SNRI are the safest medication with high efficacy for depression as well while other outcomes are relatively poor.

A specific role for serotonin in overcoming effort cost

Serotonin is implicated in many aspects of behavioral regulation. Theoretical attempts to unify the multiple roles assigned to serotonin proposed that it regulates the impact of costs, such as delay or punishment, on action selection. Here, we show that serotonin also regulates other types of action costs such as effort. We compared behavioral performance in 58 healthy humans treated during 8 weeks with either placebo or the selective serotonin reuptake inhibitor escitalopram. The task involved trading handgrip force production against monetary benefits. Participants in the escitalopram group produced more effort and thereby achieved a higher payoff. Crucially, our computational analysis showed that this effect was underpinned by a specific reduction of effort cost, and not by any change in the weight of monetary incentives. This specific computational effect sheds new light on the physiological role of serotonin in behavioral regulation and on the clinical effect of drugs for depression.

CLINICAL TRIAL REGISTRATION

ISRCTN75872983.

Excessive Iron and α-Synuclein Oligomer in Brain are Relevant to Pure Apathy in Parkinson Disease

OBJECTIVES

To investigate the demographic features, clinical features, and potential mechanism in patients with Parkinson disease (PD) with pure apathy.

METHOD

A total of 145 patients with PD without depression and dementia and 30 age-matched controls were consecutively recruited. Patients with PD were evaluated by Apathy Scale (AS), scales for motor symptoms and quality of life. The levels of iron, oxidative and neuroinflammatory factors, α-synuclein oligomer, and dopamine in cerebrospinal fluid (CSF) from patients with PD and controls were detected by enzyme-linked immunosorbent assay, chemical colorimetric method, and high-performance liquid chromatography. Comparisons between PD with pure apathy and with no pure apathy groups and correlation between AS score and the levels of above factors were analyzed.

RESULTS

There were 64 (44.14%) cases in PD-apathy group. The PD-apathy group had older age, (97.81 ± 10.82) years versus (61.86 ± 10.80) years, and severer quality of life (P < .05). The PD-apathy and PD without apathy groups presented no remarkable differences in motor symptoms (P > .05). The levels of iron, hydroxyl radical (·OH), hydrogen peroxide (H2O2), and α-synuclein oligomer in CSF in PD-apathy group were significantly higher than that in PD without the apathy group (P < .05). In patients with PD, the AS score was positively correlated with the levels of iron, ·OH, H2O2 and α-synuclein oligomer in CSF (r = 19.838, .063, 1.046, and 0.498, respectively, P < .05). In PD-apathy group, iron level was positively correlated with ·OH level (r = .011, P < .05), and H2O2 level was positively correlated with α-synuclein oligomer level in CSF (r = .045, P < .05).

CONCLUSION

Patients with PD had high prevalence of pure apathy. Patients with PD having pure apathy had older age. Pure apathy reduced quality of life for patients without worsening motor function. Excessive iron and α-synuclein oligomer in brain commonly contributed to pure apathy of PD through potential mechanism of oxidative stress.

Psychiatric Conditions in Parkinson Disease: A Comparison With Classical Psychiatric Disorders

Psychiatric conditions often complicate the outcome of patients affected by Parkinson disease (PD), but they differ from classical psychiatric disorders in terms of underlying biological mechanisms, clinical presentation, and treatment response. The purpose of the present review is to illustrate the biological and clinical aspects of psychiatric conditions associated with PD, with particular reference to the differences with respect to classical psychiatric disorders. A careful search of articles on main databases was performed in order to obtain a comprehensive review about the main psychiatric conditions associated with PD. A manual selection of the articles was then performed in order to consider only those articles that concerned with the topic of the review. Psychiatric conditions in patients with PD present substantial differences with respect to classical psychiatric disorders. Their clinical presentation does not align with the symptom profiles represented by Diagnostic and Statistical Manual for Mental Disorders and International Classification of Diseases. Furthermore, psychiatry treatment guidelines are of poor help in managing psychiatric symptoms of patients with PD. Specific diagnostic tools and treatment guidelines are needed to allow early diagnosis and adequate treatment of psychiatric conditions in comorbidity with PD.

Apathy in Parkinson's disease: clinical features, neural substrates, diagnosis, and treatment

Normal maintenance of human motivation depends on the integrity of subcortical structures that link the prefrontal cortex with the limbic system. Structural and functional disruption of different networks within these circuits alters the maintenance of spontaneous mental activity and the capacity of affected individuals to associate emotions with complex stimuli. The clinical manifestations of these changes include a continuum of abnormalities in goal-oriented behaviours known as apathy. Apathy is highly prevalent in Parkinson's disease (and across many neurodegenerative disorders) and can severely affect the quality of life of both patients and caregivers. Differentiation of apathy from depression, and discrimination of its cognitive, emotional, and auto-activation components could guide an individualised approach to the treatment of symptoms. The opportunity to manipulate dopaminergic treatment in Parkinson's disease allows researchers to study a continuous range of motivational states, from apathy to impulse control disorders. Parkinson's disease can thus be viewed as a model that provides insight into the neural substrates of apathy.

Is Dysregulation of the HPA-Axis a Core Pathophysiology Mediating Co-Morbid Depression in Neurodegenerative Diseases?

There is increasing evidence of prodromal manifestation of neuropsychiatric symptoms in a variety of neurodegenerative diseases such as Parkinson's disease (PD) and Huntington's disease (HD). These affective symptoms may be observed many years before the core diagnostic symptoms of the neurological condition. It is becoming more apparent that depression is a significant modifying factor of the trajectory of disease progression and even treatment outcomes. It is therefore crucial that we understand the potential pathophysiologies related to the primary condition, which could contribute to the development of depression. The hypothalamic-pituitary-adrenal (HPA)-axis is a key neuroendocrine signaling system involved in physiological homeostasis and stress response. Disturbances of this system lead to severe hormonal imbalances, and the majority of such patients also present with behavioral deficits and/or mood disorders. Dysregulation of the HPA-axis is also strongly implicated in the pathology of major depressive disorder. Consistent with this, antidepressant drugs, such as the selective serotonin reuptake inhibitors have been shown to alter HPA-axis activity. In this review, we will summarize the current state of knowledge regarding HPA-axis pathology in Alzheimer's, PD and HD, differentiating between prodromal and later stages of disease progression when evidence is available. Both clinical and preclinical evidence will be examined, but we highlight animal model studies as being particularly useful for uncovering novel mechanisms of pathology related to co-morbid mood disorders. Finally, we purpose utilizing the preclinical evidence to better inform prospective, intervention studies.

Anxiety and Depression Are Better Correlates of Parkinson's Disease Quality of Life Than Apathy

Due to controversy regarding the influence of apathy on quality of life (QoL), the authors examined the independent influence of apathy, depression, and trait anxiety in a nondemented sample of patients with Parkinson disease (PD). Participants (N=107) completed standard self-report measures of QoL and mood/motivation. Analyses investigated the contribution of these measures and empirically derived factor scores on QoL. QoL was predicted by trait anxiety, dysphoria, and decreased interest, with no independent contribution of apathy. Different patterns emerged with respect to domain-specific QoL, with trait anxiety being the strongest predictor across most domains. Anxiety was most widely related to QoL in PD, with minimal contribution of apathy. Future studies should examine different roles of PD mood/motivation symptoms on caregiver QoL.

Psychiatric issues in cognitive impairment

Neuropsychiatric symptoms (NPS) such as depression, hallucinations and apathy commonly occur in Parkinson's disease (PD) and have major clinical consequences including a negative impact on quality of life. This review discusses the epidemiology, clinical features, diagnostic procedures and treatment issues of NPS in PD and related disorders in the perspective of cognitive impairment, focusing on depression, anxiety, visual hallucinations, apathy, sleep disturbances, impulse control disorder and non-motor fluctuations. The majority of NPS are more common in PD patients with dementia, possibly related to shared underlying pathologies. Recent studies also suggest that NPS are associated with mild cognitive impairment in PD, in particular with the amnestic type. Accurate diagnosis of NPS is important but can be difficult, due to overlapping symptoms and similar appearance of symptoms of motor symptoms of parkinsonism, cognitive impairment, mood disorders and apathy. There are few systematic studies focusing on the management of NPS in PD with cognitive impairment.

Latent growth-curve analysis reveals that worsening Parkinson's disease quality of life is driven by depression

OBJECTIVE

Parkinson's disease (PD) is a neurodegenerative disorder resulting in a wide variety of symptoms. The current study examined the influence of apathy, depression and motor symptoms on quality of life (QoL) in PD patients. Information was drawn from an 18-month period.

METHOD

Participants (N = 397) were assessed for apathy (Apathy Scale; Starkstein et al., 1992), depression (Beck Depression Inventory-II; Beck, Steer, Ball & Ranieri, 1996), motor severity (Unified Parkinson's Disease Rating Scale, Part III; UPDRS; Fahn, Elton & Committee, 1987), and QoL (Parkinson's Disease Questionnaire-39; Jenkinson, Fitzpatrick, Peto, Greenhall, & Hyman,1997) at 3 time points: an initial clinical evaluation (baseline), a 6-month follow-up, and an 18-month follow-up. Latent growth-curve models were used to determine the influence of apathy, depression, and motor symptoms on QoL trajectories.

RESULTS

Greater difficulties with QoL at baseline showed the strongest relationship to more severe depression symptoms, followed by more severe motor symptoms, younger age, and less education (all p values < .001). Worsening of QoL over the 18-month period was only predicted by a worsening of depression (p = .003). The relationship between QoL and depression symptoms remained significant in a subsample of nondepressed PD patients.

CONCLUSION

Overall, findings from the current study suggest that self-reported QoL among PD patients is primarily related to depression. Future efforts to improving clinical care of PD patients may benefit by focusing on improving psychosocial adjustment or treatments targeting depression.

What light have resting state fMRI studies shed on cognition and mood in Parkinson's disease?

Much remains unknown about non-motor symptoms of Parkinson’s disease (PD), which have variable occurrence, progression, and severity among patients. The existing suite of neuroimaging tools has yielded insight that cannot be garnered by traditional methods such as behavioral and post-mortem assessment. They provide information on brain activity and structure that is invaluable to understanding abnormalities associated with neurodegeneration in PD. Among these tools, functional magnetic resonance imaging (fMRI) is often favored for its safety and spatial resolution. Resting state fMRI research capitalizes on the wealth of information that the brain offers when a person is not performing a motor or cognitive task. It is also a good means to study impaired and heterogeneous populations, such as people with PD. The present article reviews research that applies resting state fMRI to the ongoing hunt for biomarkers of PD non-motor symptoms. Thus far, research in this subfield has focused on two of the most common and significant non-motor symptoms: cognitive impairment and depression. These studies support resting state fMRI as a valid and practical tool for the study of these symptoms, but discrepancies among findings highlight the importance of further research with standardized procedures.

The infralimbic cortex bidirectionally modulates mesolimbic dopamine neuron activity via distinct neural pathways

The ventral tegmental area (VTA) has been implicated in a number of psychiatric disorders, including schizophrenia, depression, and bipolar disorder. One major regulator of the mesolimbic dopaminergic system is the medial prefrontal cortex (mPFC), which makes direct and indirect connections to the hippocampus and amygdala, as well as directly to the VTA. The mPFC is comprised of two subregions: the infralimbic and prelimbic cortices (ilPFC and plPFC). However, the specific roles of these subregions in regulating VTA dopamine activity have remained unclear. In this study, we aim to clarify this role and to examine the divergent neuranatomical circuits by which the mPFC regulates VTA activity. Using in vivo extracellular recordings in rats, we tested the effects of pharmacological activation (with NMDA) and inactivation (with TTX) of the ilPFC and plPFC on dopamine neuron activity, and tested the roles of the ventral subiculum (vSub) and basolateral amygdala in this process. We found that the ilPFC exerts a bidirectional control of VTA dopamine neurons, which are differentially modulated through the vSub and the basolateral amygdala. Specifically, activation or inactivation of the ilPFC attenuated or activated dopamine neuron population activity, respectively. Furthermore, dopamine activation depended on the ventral hippocampus and inactivation on the amygdala. In contrast, only inactivation of the plPFC altered dopamine neuron activity. These data indicate that the mPFC has the ability to uniquely fine-tune dopaminergic activity in the VTA. Furthermore, the data presented here suggest that the ilPFC may have a role in the pathophysiology of psychiatric disorders.

A latent class analysis of psychological disturbance in Parkinson's disease

OBJECTIVE

Psychological symptoms are common in Parkinson's disease (PD). Psychological symptoms do not respond to psychotropic medications as well in patients with PD as in patients with psychiatric illnesses who do not have PD. Evidence that PD patients can be classified into distinct psychological symptom subgroups is conflicting. This study sought to examine potential psychological heterogeneity in PD with a broader range of instruments than has been used in previous studies.

METHODS

A comprehensive battery of psychological measures assessing dysphoria, apathy, anhedonia, anxiety, and negative affect was administered to 95 PD patients without global cognitive impairment. Latent class analysis was used to identify subgroups of patients based on continuous variables derived from the psychological battery. Multinomial regression was used to examine predictors of classification.

RESULTS

The latent class analysis identified three subgroups with incremental levels of psychopathology across most symptom domains. One exception was a greater level of affective flattening in the "psychologically healthy" group compared with the "moderate symptoms" group. Greater motor dysfunction and less education were associated with greater severity of psychological symptoms.

CONCLUSIONS

These results support high psychological co-morbidity in PD, which complicates the treatment of individual symptoms. In addition, emotional blunting and anhedonia may be less indicative of widespread psychological distress than anxiety, dysphoria, and cognitive aspects of apathy. Clinicians should be aware that PD patients with greater motor dysfunction and less education are at greater risk not only for depression but also for a variety of other psychological symptoms that may not be routinely assessed.