Pathophysiology and treatment of psychosis in Parkinson's disease: a review

Inhibition of Apoptosis and Efficacy of Pan Caspase Inhibitor, Q-VD-OPh, in Models of Human Disease

Apoptosis is physiological cell death required for the cellular maintenance of homeostasis, and caspases play a major role in the execution of this process. Numerous disorders occur when levels of apoptosis within an organism are excessive, and several studies have explored the possibility of using caspase inhibitors to prevent these disorders. Q-VD-OPh (quinolyl-valyl-O-methylaspartyl-[2,6-difluorophenoxy]-methyl ketone), a novel pan caspase inhibitor, has been used because of its efficacy to inhibit apoptosis at low concentrations, its ability to cross the blood-brain barrier, as well as being nontoxic in vivo. This review examines Q-VD-OPh's ability to inhibit apoptosis in several animal models of human disease.

Cognitive correlates of psychosis in patients with Parkinson's disease

INTRODUCTION

Psychosis and hallucinations occur in 20-30% of patients with Parkinson's disease (PD). In the current study, we investigate cognitive functions in relation to the occurrence of psychosis in PD patients.

METHODS

We tested three groups of subjects - PD with psychosis, PD without psychosis and healthy controls - on working memory, learning and transitive inference tasks, which are known to assess prefrontal, basal ganglia and hippocampal functions.

RESULTS

In the working memory task, results show that patients with and without psychosis were more impaired than the healthy control group. In the transitive inference task, we did not find any difference among the groups in the learning phase performance. Importantly, PD patients with psychosis were more impaired than both PD patients without psychosis and controls at transitive inference. We also found that the severity of psychotic symptoms in PD patients [as measured by the Unified Parkinson Disease Rating Scale Thought Disorder (UPDRS TD) item] is directly associated with the severity of cognitive impairment [as measured by the mini-mental status exam (MMSE)], sleep disturbance [as measured by the Scales for Outcome in Parkinson Disease (SCOPA) sleep scale] and transitive inference (although the latter did not reach significance).

CONCLUSIONS

Although hypothetical, our data may suggest that the hippocampus is a neural substrate underlying the occurrence of psychosis, sleep disturbance and cognitive impairment in PD patients.

Musical hallucinations treated with acetylcholinesterase inhibitors

Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss.

A Long Term Effects of a New Onset Psychosis after DBS Treated with Quetiapine in a Patient with Parkinson's Disease

Deep Brain Stimulation represents a therapeutic option for PD patients. In this paper, we present and discuss a case of acute delirium and psychosis manifesting after DBS in a 58-years-old man affected by Parkinson's Disease. We highlight the importance of an exhaustive psychiatric evaluation in candidates for DBS and we underline the severity and non-reversibility of some adverse events associated with the implantation, suggesting the use of Quetiapine in the management of these effects. Acute psychosis may be listed as a potential severe adverse event associated with DBS, even in patients without a clear cut previous history of psychiatric disorders.

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.

Visual hallucinations in Parkinson's disease: theoretical models

One of the most challenging tasks in neuroscience is to be able to meaningfully connect information across the different levels of investigation, from molecular or structural biology to the resulting behavior and cognition. Visual hallucinations are a frequent occurrence in Parkinson's disease and significantly contribute to the burden of the disease. Because of the widespread pathological processes implicated in visual hallucinations in Parkinson's disease, a final common mechanism that explains their manifestation will require an integrative approach, in which consideration is taken across all complementary levels of analysis. This review considers the leading hypothetical frameworks for visual hallucinations in Parkinson's disease, summarizing the key aspects of each in an attempt to highlight the aspects of the condition that such a unifying hypothesis must explain. These competing hypotheses include implications of dream imagery intrusion, deficits in reality monitoring, and impairments in visual perception and attention.

Neuromelanin magnetic resonance imaging reveals increased dopaminergic neuron activity in the substantia nigra of patients with schizophrenia

PURPOSE

The dopamine hypothesis suggests that excessive dopamine release results in the symptoms of schizophrenia. The purpose of this study was to elucidate the dopaminergic and noradrenergic neurons using 3-T neuromelanin magnetic resonance imaging (MRI) in patients with schizophrenia and healthy control subjects.

METHODS

We prospectively examined 52 patients with schizophrenia (M: F = 27∶25, mean age, 35 years) and age- and sex-matched healthy controls. Using a 3T MRI unit, we obtained oblique T1-weighted axial images perpendicular to the brainstem. We measured the signal intensity and area for the substantia nigra (SNc), midbrain tegmentum, locus ceruleus (LC), and pons. We then calculated the contrast ratios (CR) for the SNc (CRSN) and LC (CRLC), which were compared between patients and healthy controls using unpaired t-tests.

RESULTS

The SNc and LC were readily identified in both patients and healthy controls as areas with high signal intensities in the posterior part of the cerebral peduncle and in the upper pontine tegmentum. The CRSN values in patients were significantly higher than those in healthy controls (10.89±2.37 vs. 9.6±2.36, p<0.01). We observed no difference in the CRLC values between the patients and healthy controls (14.21±3.5 vs. 13.44±3.37, p = 0.25). Furthermore, there was no difference in area of the SNc and LC between schizophrenia patients and controls.

CONCLUSIONS

Neuromelanin MRI might reveal increased signal intensity in the SNc of patients with schizophrenia. Our results indicate the presence of excessive dopamine products in the SNc of these patients.

Correlation of sleep disturbance and cognitive impairment in patients with Parkinson's disease

OBJECTIVE

Cognitive impairment is a common nonmotor symptom of Parkinson's disease (PD) and is associated with high mortality, caregiver distress, and nursing home placement. The risk factors for cognitive decline in PD patients include advanced age, longer disease duration, rapid eye movement sleep behavior disorder, hallucinations, excessive daytime sleepiness, and nontremor symptoms including bradykinesia, rigidity, postural instability, and gait disturbance. We conducted a cross-sectional study to determine which types of sleep disturbances are related to cognitive function in PD patients.

METHODS

A total of 71 PD patients (29 males, mean age 66.46 ± 8.87 years) were recruited. All patients underwent the Mini- Mental State Examination (MMSE) and the Korean Version of the Montreal Cognitive Assessments (MoCA-K) to assess global cognitive function. Sleep disorders were evaluated with the Stanford Sleepiness Scale, Epworth Sleepiness Scale, Insomnia Severity Index (ISI), Pittsburg Sleep Quality Index, and Parkinson's Disease Sleep Scale in Korea (PDSS).

RESULTS

The ISI was correlated with the MMSE, and total PDSS scores were correlated with the MMSE and the MoCA-K. In each item of the PDSS, nocturnal restlessness, vivid dreams, hallucinations, and nocturnal motor symptoms were positively correlated with the MMSE, and nocturnal restlessness and vivid dreams were significantly related to the MoCA-K. Vivid dreams and nocturnal restlessness are considered the most powerful correlation factors with global cognitive function, because they commonly had significant correlation to cognition assessed with both the MMSE and the MoCA-K.

CONCLUSIONS

We found a correlation between global cognitive function and sleep disturbances, including vivid dreams and nocturnal restlessness, in PD patients.

Neural and behavioral substrates of subtypes of Parkinson's disease

Parkinson’s disease (PD) is a neurological disorder, associated with rigidity, bradykinesia, and resting tremor, among other motor symptoms. In addition, patients with PD also show cognitive and psychiatric dysfunction, including dementia, mild cognitive impairment (MCI), depression, hallucinations, among others. Interestingly, the occurrence of these symptoms—motor, cognitive, and psychiatric—vary among individuals, such that a subgroup of PD patients might show some of the symptoms, but another subgroup does not. This has prompted neurologists and scientists to subtype PD patients depending on the severity of symptoms they show. Neural studies have also mapped different motor, cognitive, and psychiatric symptoms in PD to different brain networks. In this review, we discuss the neural and behavioral substrates of most common subtypes of PD patients, that are related to the occurrence of: (a) resting tremor (vs. nontremor-dominant); (b) MCI; (c) dementia; (d) impulse control disorders (ICD); (e) depression; and/or (f) hallucinations. We end by discussing the relationship among subtypes of PD subgroups, and the relationship among motor, cognitive, psychiatric factors in PD.

A case in which mirtazapine reduced auditory hallucinations in a patient with Parkinson disease

A 48-year-old woman with Parkinson disease (PD) suffered from auditory hallucinations (AH). We had treated her with a reduction in antiparkinsonian agents and the use of atypical antipsychotic agents. However, her symptoms did not improve, and her extrapyramidal symptoms (EPS) worsened. To lessen her depressive symptoms, treatment with a new-generation antidepressant, mirtazapine (MRZ), was commenced. The patient's AH gradually decreased with no worsening of EPS, and the AH disappeared 4 weeks after the commencement of treatment with MRZ. The present case suggests the effectiveness of MRZ for the treatment of refractory AHs in patients with PD.

Advances in the treatment of visual hallucinations in neurodegenerative diseases

Treatment of visual hallucinations in neurodegenerative disorders is not well advanced. The complexity of underlying mechanisms presents a number of potential avenues for developing treatments, but also suggests that any single one may be of limited efficacy. Reducing medication, with the careful introduction of antidementia medication if needed, is the mainstay of current management. Antipsychotic medication leads to excessive morbidity and mortality and should only be used in cases of high distress that do not otherwise respond. Education, reduction of risk factors and psychological treatments have limited evidence of efficacy, but are unlikely to cause harm.

Neuropsychiatric symptoms in Nigerian patients with Parkinson's disease

BACKGROUND

Neuropsychiatric symptoms are common in Parkinson's disease and may precede onset of motor symptoms. They are also known to increase caregiver's burden.

OBJECTIVE

The aim of this study was to assess neuropsychiatric symptoms in a cohort of Nigerian patients with idiopathic Parkinson's disease and compare with systemic hypertension.

METHOD

Fifty patients with idiopathic Parkinson's disease were compared with fifty demographically matched controls with systemic hypertension. Diagnosis of Parkinson's disease was based on the United Kingdom Parkinson Disease Society (UKPDS) Brain Bank Clinical diagnostic Criteria. Diagnosis of hypertension was based on recorded blood pressure of ≥140/90 mmHg on two different occasions. The Neuropsychiatric Inventory (NPI) was applied to caregivers of both patients and controls.

RESULTS

There were significant differences in frequency of neuropsychiatric symptoms in patients and controls (P < 0.05). Significant differences were found in mean distress scores for some neuropsychiatric symptoms and the total mean distress score. In all cases, patients with Parkinson's disease had higher scores when compared with controls. Severity of motor symptoms, as measured by the UKPDS, correlated with total NPI severity scores (P = 0.000).

CONCLUSION

Neuropsychiatric symptoms occur more frequently in Parkinson's disease than matched controls, and the presence of these symptoms is associated with caregivers' distress. There is a need for early and adequate treatment for motor and behavioural symptoms of Parkinson's disease.

Mirtazapine improves visual hallucinations in Parkinson's disease: a case report

Psychotic symptoms often occur as a complication in Parkinson's disease patients, and a set of criteria for Parkinson's disease with psychosis (PDPsy) has been established. Among these criteria, hallucinations are one of the specific symptoms, with visual hallucinations being the most common. While atypical antipsychotic agents are often used for the treatment of PDPsy, adverse effects, including extrapyramidal symptoms, often hinder its continuation or tolerance. There have been some reports and reviews indicating that antidepressants may be effective for PDPsy and other forms of dementia with psychosis. In this report, we present a patient with PDPsy who was treated with one of the new-generation antidepressants, mirtazapine. Mirtazapine improved the patient's refractory psychotic symptoms, especially her visual hallucinations, without worsening her motor symptoms.

Neuropsychopharmacology of auditory hallucinations: insights from pharmacological functional MRI and perspectives for future research

Experiencing auditory verbal hallucinations is a prominent symptom in schizophrenia that also occurs in subjects at enhanced risk for psychosis and in the general population. Drug treatment of auditory hallucinations is challenging, because the current understanding is limited with respect to the neural mechanisms involved, as well as how CNS drugs, such as antipsychotics, influence the subjective experience and neurophysiology of hallucinations. In this article, the authors review studies of the effect of antipsychotic medication on brain activation as measured with functional MRI in patients with auditory verbal hallucinations. First, the authors examine the neural correlates of ongoing auditory hallucinations. Then, the authors critically discuss studies addressing the antipsychotic effect on the neural correlates of complex cognitive tasks. Current evidence suggests that blood oxygen level-dependant effects of antipsychotic drugs reflect specific, regional effects but studies on the neuropharmacology of auditory hallucinations are scarce. Future directions for pharmacological neuroimaging of auditory hallucinations are discussed.

Residual dopamine receptor desensitization following either high- or low-dose sub-chronic prior exposure to the atypical anti-psychotic drug olanzapine

RATIONALE

Anti-psychotic drugs are antagonists of dopamine D2 receptors and repeated administration may lead to the development of dopamine receptor supersensitivity.

OBJECTIVES

The objective of this study is to investigate the effects of sub-chronic olanzapine treatments upon the induction of dopamine receptor supersensitivity.

METHODS

Rats were administered ten daily low or high doses of the atypical anti-psychotic drug olanzapine (0.01 or 1.0 mg/kg). After 5 days of withdrawal, all groups received 2.0 mg/kg apomorphine on five successive days. Five days after the apomorphine sensitization protocol, in separate experiments, either a conditioning test or an apomorphine sensitization test was conducted.

RESULTS

During the anti-psychotic treatment the high dose of olanzapine induced profound locomotion suppression, whereas the low dose had no effect upon locomotion. The apomorphine treatments given to the vehicle control group generated locomotor sensitization. This sensitization effect was attenuated by the same degree for both the low or high dose prior olanzapine treatments. Also, the low and high-dose olanzapine pre-treatments diminished subsequent apomorphine-conditioned and apomorphine-sensitized locomotor responses.

CONCLUSIONS

The equivalent attenuation of the apomorphine sensitization produced by both olanzapine doses indicates that this effect was unrelated to the direct effects of olanzapine upon locomotion. Furthermore, the persistence of the desensitization effects well after the termination of the olanzapine treatments is indicative of a residual desensitization of the dopamine system. These findings are of importance when considering the use of atypical anti-psychotic drugs in the treatment of psychoses and other disorders in which overactivity of the dopamine system is considered a contributory factor.

Ziprasidone versus clozapine in the treatment of psychotic symptoms in Parkinson disease: a randomized open clinical trial

OBJECTIVE

To compare the efficacy and safety of ziprasidone versus clozapine in patients with psychotic symptoms in Parkinson disease.

METHODS

A 4-week, randomized, single-blind, open-label, parallel comparison of ziprasidone and clozapine was completed. Sixteen patients with Parkinson disease were included. Psychosis was assessed using the Brief Psychiatric Rating Scale (BPRS), and the Scale for the Assessment of Positive Symptoms (SAPS). The Unified Parkinson's Disease Rating Scale and the Abnormal Involuntary Movement Scale were used to assess motor conditions during the study period. Measures of drugs' adverse effects, white blood cell count, and the Clinical Global Impression Scale-Severity Subscale were performed. Cognitive changes were assessed with the Mini-Mental State Examination.

RESULTS

Fourteen patients completed the study, 8 patients on clozapine and 6 patients on ziprasidone. The final mean dosage for clozapine was 32.14 mg/d and that for ziprasidone was 35 mg/d. Throughout the study, neither the Unified Parkinson's Disease Rating Scale, the Abnormal Involuntary Movement Scale, or the Mini-Mental State Examination showed statistical differences in both groups. Psychotic symptoms, assessed with SAPS and BPRS, were reduced in both groups but with more intensity in the ziprasidone group (effect size in SAPS, 1.3, and effect size in BPRS, 1.7) than in the clozapine group (effect size in SAPS, 0.36, and effect size in BPRS, 0.53).

CONCLUSIONS

Ziprasidone seems to be at least as effective as clozapine in the treatment to ameliorate psychotic symptoms in PD.

Anxiety disorders, physical illnesses, and health care utilization in older male veterans with Parkinson disease and comorbid depression

This study examined the rates of anxiety and depressive disorders, physical illnesses, and health service use in male patients 55 years or older with a diagnosis of Parkinson disease who were seen at least twice at the 10 medical centers in the Veterans Affairs Healthcare Network of the South Central region of the United States. Of the 273 male patients diagnosed between October 1, 1997, and September 30, 2009, 62 (22.7%) had a depressive disorder. The overall prevalence of anxiety disorders was 12.8%; patients with comorbid depression had a 5-fold greater prevalence of anxiety disorders than those without depression (35.5% vs 6.2%, P<.0001). Patients with comorbid depression also had increased prevalence of all physical illnesses examined and more outpatient clinic and mental health visits. Patients with Parkinson disease and comorbid depression are more likely to have anxiety disorders and several physical illnesses, to be using antipsychotic and dementia medicines, and to have increased health service utilization than those without depression.

Neuroinflammation and non-motor symptoms: the dark passenger of Parkinson's disease?

Generally speaking, inflammation as a key piece to the Parkinson's disease (PD) puzzle is a relatively new concept. Acceptance of this concept has gained ground as studies by various researchers have demonstrated the potential of mitigating nigral cell death by curtailing inflammation in animal models of PD. We propose that the significance of inflammation in PD pathology may extend beyond the nigrostriatal region. In the current review, we present an argument for this based on the Braak staging and discuss how inflammation might contribute to the development of non-motor PD symptoms.

Agitation and psychosis associated with dementia with lewy bodies exacerbated by modafinil use

Dementia with Lewy bodies (DLB) is commonly associated with excessive daytime somnolence (EDS). Modafinil is a wakefulness-promoting agent that is considered to have limited interaction with the dopaminergic system. As individuals with DLB are predisposed to psychotic symptoms that might be exacerbated by dopaminergic stimulation, modafinil is considered to be an attractive option for the treatment of EDS in DLB. We describe 2 cases in which administration of modafinil exacerbated agitation and hallucinations in DLB, and we also review data that may explain the mechanisms underlying this effect. In both cases, psychotic symptoms emerged concomitantly with modafinil administration and remitted following its discontinuation. Although definitive data regarding the benefits and adverse effects of modafinil for the treatment of EDS in DLB await controlled prospective randomized studies, our observations warrant caution regarding its use in this context.

Profile and variables related to antipsychotic consumption according to dementia subtypes

BACKGROUND

Antipsychotics (APs) are usually prescribed to deal with behavioral and psychological symptoms of dementia (BPSD), but poor outcomes, important side effects, and high mortality risk should be addressed. The aim of this study was to estimate the prevalence of AP consumption in patients with dementia, and to describe and compare the sociodemographic and clinical characteristics of patients consuming APs.

METHODS

This was a cross-sectional study using 1,894 cases of dementia registered from 2007 to 2009 by the Registry of Dementias of Girona (ReDeGi), which is a population-based passive surveillance system of dementia diagnoses. APs were categorized according to the anatomical therapeutic chemical (ATC) classification, and grouped as typical antipsychotics (TAPs) or atypical antipsychotics (AAPs). Binary logistic regression analyses were used to detect the predictors of AP use as well as the variables associated with TAP or AAP prescription.

RESULTS

APs were used in 29.6% of the cases, with Parkinsonian syndromes (PSd) being the subtype of dementia with the highest AP prescription (50.6% of the patients with PSd). AAPs were mainly prescribed in all subtypes of dementia, except in vascular dementia (VaD) and PSd, where no preference in TAP or AAP use was found. Psychotic antecedents, dementia with Lewy bodies (DLB) diagnoses, cognitive impairment, and BPSD were AP use predictors. AAP use was related to higher severity of dementia.

CONCLUSIONS

Despite their disputed benefit-risk ratios, APs are extensively used, off-label, to treat BPSD, and AAPs are more commonly prescribed than TAPs. AP consumption was frequent in DLB, and was related to dementia severity indicators.

Paradoxical and bidirectional drug effects

A paradoxical drug reaction constitutes an outcome that is opposite from the outcome that would be expected from the drug's known actions. There are three types: 1. A paradoxical response in a condition for which the drug is being explicitly prescribed. 2. Paradoxical precipitation of a condition for which the drug is indicated, when the drug is being used for an alternative indication. 3. Effects that are paradoxical in relation to an aspect of the pharmacology of the drug but unrelated to the usual indication. In bidirectional drug reactions, a drug may produce opposite effects, either in the same or different individuals, the effects usually being different from the expected beneficial effect. Paradoxical and bidirectional drug effects can sometimes be harnessed for benefit; some may be adverse. Such reactions arise in a wide variety of drug classes. Some are common; others are reported in single case reports. Paradoxical effects are often adverse, since they are opposite the direction of the expected effect. They may complicate the assessment of adverse drug reactions, pharmacovigilance, and clinical management. Bidirectional effects may be clinically useful or adverse. From a clinical toxicological perspective, altered pharmacokinetics or pharmacodynamics in overdose may exacerbate paradoxical and bidirectional effects. Certain antidotes have paradoxical attributes, complicating management. Apparent clinical paradoxical or bidirectional effects and reactions ensue when conflicts arise at different levels in self-regulating biological systems, as complexity increases from subcellular components, such as receptors, to cells, tissues, organs, and the whole individual. These may be incompletely understood. Mechanisms of such effects include different actions at the same receptor, owing to changes with time and downstream effects; stereochemical effects; multiple receptor targets with or without associated temporal effects; antibody-mediated reactions; three-dimensional architectural constraints; pharmacokinetic competing compartment effects; disruption and non-linear effects in oscillating systems, systemic overcompensation, and other higher-level feedback mechanisms and feedback response loops at multiple levels. Here we review and provide a compendium of multiple class effects and individual reactions, relevant mechanisms, and specific clinical toxicological considerations of antibiotics, immune modulators, antineoplastic drugs, and cardiovascular, CNS, dermal, endocrine, musculoskeletal, gastrointestinal, haematological, respiratory, and psychotropic agents.

Nonmotor manifestations in Parkinson disease

BACKGROUND

Although the diagnosis of Parkinson disease (PD) still relies mainly on the appearance of its classical motor features of resting tremor, rigidity, bradykinesia, and postural instability, nonmotor manifestations in PD are now recognized as an integral component of this multisystem disorder.

REVIEW SUMMARY

Nonmotor complications in PD occur commonly. The current understanding of cognitive dysfunction; neuropsychiatric manifestations including psychosis, impulsive control, and compulsive disorders, depression, anxiety and apathy; autonomic complications such as hypotension, erectile dysfunction, and urinary complications; sleep disorders and other nonmotor manifestations are summarized in this review.

CONCLUSION

Nonmotor complications often carry a greater impact than motor features in PD. Therefore, heightened awareness and proper recognition of these features are critical in improving a Parkinson patient's quality of life.

Activation of nociceptin/orphanin FQ peptide receptors disrupts visual but not auditory sensorimotor gating in BALB/cByJ mice: comparison to dopamine receptor agonists

Nociceptin/orphanin FQ (N/OFQ) peptide and its receptor (NOP receptor) have been implicated in a host of brain functions and diseases, but the contribution of this neuropeptide system to behavioral processes of relevance to psychosis has not been investigated. We examined the effect of the NOP receptor antagonists, Compound 24 and J-113397, and the synthetic agonist, Ro64-6198, on time function (2-2000 ms prepulse-pulse intervals) of acoustic (80 dB/10 ms prepulse) and visual (1000 Lux/20 ms prepulse) prepulse inhibition of startle reflex (PPI), a preattentive sensory filtering mechanism that is central to perceptual and mental integration. The effects of the dopamine D1-like receptor agonist, SKF-81297, the D2-like receptor agonist, quinelorane, and the mixed D1/D2 agonist, apomorphine, were studied for comparison. When acoustic stimulus was used as prepulse, BALB/cByJ mice displayed a monotonic time function of PPI, and consistent with previous studies, apomorphine and SKF-81279 induced PPI impairment, whereas quinelorane had no effect. None of the NOP receptor ligands was effective on acoustic PPI. When flash light was used as prepulse, BALB/cByJ mice displayed a bell-shaped time function of PPI and all dopamine agonists were active. Ro64-6198 was also effective in reducing visual PPI. NOP receptor antagonists showed no activity but blocked disruptive effect of Ro64-6198. Finally, coadministration of the typical antipsychotic, haloperidol, attenuated PPI impairment induced by Ro64-6198, revealing involvement of a dopaminergic component. These findings show that pharmacological stimulation of NOP or dopamine D2-like receptors is more potent in disrupting visual than acoustic PPI in mice, whereas D1-like receptor activation disrupts both. They further suggest that dysfunction of N/OFQ transmission may be implicated in the pathogenesis of psychotic manifestations.

Adenosine A(2A) Receptor Antagonists Do Not Disrupt Rodent Prepulse Inhibition: An Improved Side Effect Profile in the Treatment of Parkinson's Disease

Parkinson's disease (PD) is characterized by loss of dopaminergic neurons in the substantia nigra. Current treatments for PD focus on dopaminergic therapies, including L-dopa and dopamine receptor agonists. However, these treatments induce neuropsychiatric side effects. Psychosis, characterized by delusions and hallucinations, is one of the most serious such side effects. Adenosine A_2A receptor antagonism is a nondopaminergic treatment for PD with clinical and preclinical efficacy. The present studies assessed A_2A antagonists SCH 412348 and istradefylline in rodent prepulse inhibition (PPI), a model of psychosis. Dopamine receptor agonists pramipexole (0.3–3 mg/kg), pergolide (0.3–3 mg/kg), and apomorphine (0.3–3 mg/kg) significantly disrupted PPI; ropinirole (1–30 mg/kg) had no effect; L-dopa (100–300 mg/kg) disrupted rat but not mouse PPI. SCH 412348 (0.3–3 mg/kg) did not disrupt rodent PPI; istradefylline (0.1–1 mg/kg) marginally disrupted mouse but not rat PPI. These results suggest that A_2A antagonists, unlike dopamine agonists, have an improved neuropsychiatric side effect profile.

Clinicopathological correlates of behavioral and psychological symptoms of dementia

Behavioral and psychological symptoms are commonly observed in a majority of demented patients at some time during the course of their illness. Many of these psychiatric manifestations, especially those related to mood, may be early expressions of dementia and/or mild cognitive impairment. The literature suggests that behavioral and psychological symptoms of dementia (BPSD) are an integral part of the disease process. The dissociation, in many cases, between BPSD and the rather linear decline in cognitive functions suggests that independent pathophysiological mechanisms give rise to these symptoms. A review of the neuroimaging and neuropathology literature indicates that BPSD are the expression of regional rather than diffuse brain pathology. Psychotic symptoms in demented patients usually demonstrate preferential involvement of the frontal lobe and/or limbic regions. Visual hallucinations differentiate themselves from other psychotic symptoms by their tendency to involve the occipital lobes. There is a significant association between apathy and structural changes of the anterior cingulate gyrus. White matter hyperintensities occur in a significant number of depressed patients; otherwise, there is lack of association between depression and either specific brain changes or affected regions. Strictly neuropathological explanations are likely to be insufficient to explain BPSD. Environmental changes, neurochemical abnormalities, past psychiatric history (including premorbid personality), social history (e.g., intellectual achievement and life-long learning), family history, and genetic susceptibility are factors, among others, that influence BPSD.

Palliative care in Parkinson's disease: role of cognitive behavior therapy

BACKGROUND

Parkinson's disease (PD) is a chronic, progressive, neurodegenerative disorder that leads to the classic features of akinesia (encompassing hypokinesia and bradykinesia), tremor, rigidity and postural instability. Other non-motor complications include depression, fatigue, pain, and sleep disturbances. For the management of these complications, non-pharmacological techniques, such as Cognitive-behavioral therapy (CBT) can be used. This can focus on overt behavior and underlying cognitions and train the patient in coping strategies to obtain better symptom control.

OBJECTIVES

To review studies on CBT as palliative care in PD patients.

MATERIALS AND METHODS

A survey was conducted for all available English-language studies by means of a MEDLINE search. Keywords in the searches included Parkinson's disease, palliative care, and cognitive behavior therapy. All articles that reported the cognitive behavior therapy and palliative care in a group of PD patients regardless of the method used by the researchers were identified and analyzed.

RESULT AND CONCLUSION

CBT has a strong evidence base for its use and has proven to be an effective treatment in management of people with chronic pain, fatigue syndrome, depression and sleep disturbances, with efficacy that lasts beyond the duration of treatment. Although PD patients suffer from these complications, there are only a few studies on administration of CBT on them. Considering its effectiveness, CBT can be used as an option for palliative care for PD patients, directed toward improving the patient's functional status, clinical disability and quality of life. Further studies are required in this area.

The pedunculopontine nucleus is related to visual hallucinations in Parkinson's disease: preliminary results of a voxel-based morphometry study

Visual hallucinations (VH) are common in Parkinson’s disease (PD) and lead to a poor quality of life. For a long time, dopaminergic therapy was considered to be the most important risk factor for the development of VH in PD. Recently, the cholinergic system, including the pedunculopontine nucleus (PPN), has been implicated in the pathophysiology of VH. The aim of the present study was to investigate grey matter density of the PPN region and one of its projection areas, the thalamus. Thirteen non-demented PD patients with VH were compared to 16 non-demented PD patients without VH, 13 demented PD patients (PDD) with VH and 11 patients with dementia with Lewy bodies (DLB). Isotropic 3-D T1-weighted MRI images (3T) were analysed using voxel-based morphometry (VBM) with the PPN region and thalamus as ROIs. PD and PDD patients with VH showed grey matter reductions of the PPN region and the thalamus compared to PD patients without VH. VH in PD(D) patients are associated with atrophy of the PPN region and its thalamic target area, suggesting that a cholinergic deficit may be involved in the development of VH in PD(D).

Incidence, prescription patterns, and determinants of antipsychotic use in patients with Parkinson's disease

Empirical data regarding the choice of antipsychotics for the management of psychosis in patients with Parkinson's disease are limited. This study aimed to evaluate the incidence and prescribing patterns of antipsychotics and to determine the predictors associated with the prescribing of typical antipsychotics in patients with Parkinson's disease. This was a retrospective cohort study analyzing data from the National Health Insurance Research Database in Taiwan between January 1, 2000, and December 31, 2006, in which patients with Parkinson's disease (ICD-9-CM codes 332) initially receiving any antiparkinsonian drug (n = 2095) were followed up to evaluate the subsequent use of antipsychotics. Kaplan-Meier statistics and multiple logistic regression were employed to evaluate the cumulative probability of antipsychotic use and determinants of prescribing of typical antipsychotics, respectively. The cumulative probability of initiation of an antipsychotic within 6 years was found to be 51%, and the proportion of patients who began taking an atypical antipsychotic increased from 11.1% in 2001 to 36.1% in 2005. Physician specialty was found to be the most influential predictor of the prescribing of typical antipsychotics: physicians with an internal medicine specialty were 10.62 times more likely (95% confidence interval, 4.64-24.32) to prescribe typical antipsychotics than were neurologists. The use of antipsychotics in Parkinson's disease is common, and the use of typical antipsychotics dominates antipsychotic treatment. Particular attention needs to be paid to improving practice, including efforts that encourage primary care providers to have the appropriate choice of antipsychotics in patients with Parkinson's disease.

[Psychopathological syndromes of neurological diseases in the elderly]

Vascular and degenerative diseases of the central nervous system are one of the most common health problems in the elderly. Cognitive dysfunction, mood disorders and behavioural changes as well as psychotic symptoms constitute an invariable part of the clinical manifestation of these diseases. Psychopathological syndromes influence management decisions, commonly being a reason for patients' institutionalization; they are also a cause of suffering of patients and their caregivers and relatives. Relevant diagnosis of psychological symptoms is crucial in establishing adequate therapy, which improves quality of life of patients and their caregivers. The paper provides an overview of the psychopathological presentation of the most common central nervous system diseases in the elderly.

Therapeutic potential of targeting group III metabotropic glutamate receptors in the treatment of Parkinson's disease

Current drugs used in the treatment of Parkinson's disease (PD), for example, L-DOPA and dopamine agonists, are very effective at reversing the motor symptoms of the disease. However, they do little to combat the underlying degeneration of dopaminergic neurones in the substantia nigra pars compacta (SNc) and their long-term use is associated with the appearance of adverse effects such as L-DOPA-induced dyskinesia. Much emphasis has therefore been placed on finding alternative non-dopaminergic drugs that may circumvent some or all of these problems. Group III metabotropic glutamate (mGlu) receptors were first identified in the basal ganglia a decade ago. One or more of these receptors (mGlu4, mGlu7 or mGlu8) is found on pre-synaptic terminals of basal ganglia pathways whose overactivity is implicated not only in the generation of motor symptoms in PD, but also in driving the progressive SNc degeneration. The finding that drugs which activate group III mGlu receptors can inhibit transmission across these overactive synapses has lead to the proposal that group III mGlu receptors are promising targets for drug discovery in PD. This paper provides a comprehensive review of the role and target potential of group III mGlu receptors in the basal ganglia. Overwhelming evidence obtained from in vitro studies and animal models of PD supports group III mGlu receptors as potentially important drug targets for providing both symptom relief and neuroprotection in PD.

Clinical review of treatment options for select nonmotor symptoms of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is associated with a host of nonmotor symptoms, including psychosis, cognitive impairment, depression, sleep disturbance, swallowing disorders, gastrointestinal symptoms, and autonomic dysfunction. The nonmotor symptoms of PD have the potential to be more debilitating than the motor features of the disorder.

OBJECTIVE

The aim of this article was to review treatment options for the nonmotor manifestations of PD, including pharmacologic and nonpharmacologic interventions.

METHODS

The PubMed and MEDLINE databases were searched for articles published in English between January 1966 and April 2010, using the terms Parkinson's disease, nonmotor, psychosis, hallucination, antipsychotic, cognitive impairment, dementia, depression, sleep disturbance, sleepiness, REM (rapid eye movement) sleep behavior disorder, dysphagia, swallowing disorder, sialorrhea, gastrointestinal, constipation, autonomic dysfunction, orthostatic hypotension, gastroparesis, erectile dysfunction, sexual dysfunction, and urinary dysfunction. Articles were selected for review if they were randomized controlled trials (RCTs), meta-analyses, or evidence-based reviews of treatment of patients with PD, and/or expert opinion regarding the treatment of nonmotor symptoms of PD.

RESULTS

A total of 148 articles, including RCTs, meta-analyses, and evidence-based reviews, were included in this review. The treatment of hallucinations or psychosis in PD should include a stepwise reduction in medications for motor symptoms, followed by the use of quetiapine or clozapine. Dementia may be treated with acetylcholinesterase inhibitors. Evidence is lacking concerning the optimal pharmacologic treatment for depression in PD, with expert opinions indicating selective serotonin reuptake inhibitors as the antidepressants of choice. However, the largest study to date found nortriptyline therapy to be efficacious compared with placebo, whereas paroxetine controlled release was not. A variety of sleep disturbances may plague a person with PD, and treatment must be individualized to the patient's specific sleep disturbance pattern and contributing factors. Swallowing disorders may lead to aspiration and pneumonia, and patients with dysphagia should be referred to a speech therapist for further evaluation and treatment. Orthostasis may be treated with nonpharmacologic interventions as well as pharmacologic treatments (eg, fludrocortisone, midodrine, indomethacin). Other autonomic symptoms are managed in a manner similar to that in patients without PD, although careful attention must be aimed at avoiding dopamine-blocking therapies in the treatment of gastrointestinal dysfunction and gastroparesis.

CONCLUSIONS

Various pharmacologic and nonpharmacologic strategies are available for the management of the nonmotor symptoms of PD. The challenges associated with nonmotor symptoms must not be forgotten in light of the motor symptoms of PD, and treatment of nonmotor symptoms should be encouraged.

Parkinson's psychosis

OPINION STATEMENT

Psychosis is a leading reason for nursing home placement of patients with Parkinson's disease (PD). It may also be the single greatest stressor for caregivers of PD patients, it is generally persistent, and its presence markedly increases the risk of mortality. For these reasons, it is essential to recognize and appropriately treat psychosis in PD. Treatment of psychotic symptoms should be initiated after potential medical and environmental causes of delirium (eg, infection) have been eliminated or addressed. Initial pharmacologic changes should include limiting the patient's anti-PD medications to those that are necessary to preserve motor function (ie, eliminating adjunctive agents). Should that fail, an atypical antipsychotic agent is the treatment of choice. Clozapine is presently the gold standard, and quetiapine represents another option because of its ease of use and good tolerability profile. Emerging treatment options include the use of acetylcholinesterase inhibitors, antidepressants, and cognitive behavioral therapy. This article reviews what is currently known about treatment strategies in PD psychosis.

Current strategies in the treatment of Parkinson's disease and a personalized approach to management

Parkinson's disease is a progressive, neurodegenerative disorder affecting millions of people worldwide. Given the aging population, the prevalence of the disease is expected to increase substantially. The mainstay of treatment has been dopamine replacement therapy with carbidopa, levodopa, dopamine agonists, monoamine oxidase type B inhibitors, catechol-O-methyltransferase inhibitors and amantadine. Nonmotor features, such as cognitive impairment, mood disorders, autonomic dysfunction, gastrointestinal and genitourinary dysfunction, have a substantial impact on Parkinson's disease patients and their quality of life. This review will provide an overview on medications currently available for management of both motor and nonmotor symptoms of Parkinson's disease. Focus will be placed on recent and evolving studies evaluating symptomatic and neuroprotective effects of medications, and how such studies may impact the future management of Parkinson's disease.

Uneventful electroconvulsive therapy in a patient with dopa-responsive dystonia (Segawa syndrome)

BACKGROUND

The Segawa syndrome is an autosomal dominant form of guanosine triphosphate cyclohydrolase deficiency, resulting in decreased dopamine and serotonin levels, typically presenting as a dopa-responsive dystonia.

METHOD

Case presentation of a 56-year-old man with dopa-responsive dystonia, treated with electroconvulsive therapy for a psychotic depression.

RESULTS

Scores on the Inventory of Depressive Symptomatology dropped from 35 before treatment to 3 after the eighth treatment session. Etomidate and succinylcholine were used as anesthetics. Apart from 2 sessions with postictal agitation, the course of electroconvulsive therapy was finished uneventfully. Electroconvulsive therapy and anesthesia had no untoward effects on motor function.

CONCLUSIONS

Electroconvulsive therapy can be administered safely and effectively in a patient with dopa-responsive dystonia (Segawa syndrome).

An Exploratory Retrospective Evaluation of Ropinirole-Associated Psychotic Symptoms in an Outpatient Population Treated for Restless Legs Syndrome or Parkinson's Disease

Background:

Traditional treatment approaches for the management of restless legs syndrome (RLS) and Parkinson's disease (PD) include the use of medications that either directly or indirectly increase dopamine levels. In turn, a potential adverse event that could be expected is the development or exacerbation of psychiatric-related symptoms.

Objective:

To evaluate and describe the incidence of psychosis and associated behavioral features in patients taking ropinirole for RLS or PD.

Methods:

Patients were identified from a computerized database search of outpatients being treated with ropinirole for 1 of 2 medical conditions: PD or RLS. Data were collected in a retrospective manner from 95 patients who were tracked over the course of their therapy to determine whether psychosis or associated behavioral symptoms developed as a result and whether an intervention was needed to adjust ropinirole dosing or if additional medications had to be added to control features associated with psychosis.

Results:

A total of 284 patients being treated for RLS or PD were identified; of this group, 95 patients were identified as being treated for PD or RLS with ropinirole. Of the 95 patients being treated with ropinirole, 13 developed psychotic features that required therapeutic intervention with either the use of an antipsychotic or dose adjustment of ropinirole. PD patients included in this study were numerically more likely to develop psychotic features compared with RLS patients; however, the difference was not statistically significant (p = 0.122). The results do suggest that this risk is increased when ropinirole is used as part of a dual therapy approach with dopamine agonists in the treatment of either PD or RLS (p = 0.003).

Discussion:

Dopamine agonists have long been used as preferred treatment in the management of PD and RLS. When treating either PD or RLS in the psychiatric population, the concern arises that increased activity at dopamine receptors may induce or exacerbate psychiatric features. A potential clinical concern with the use of ropinirole is the potential for patients to develop psychiatric features, although there are few data available to demonstrate whether stimulation of targeted individual dopamine receptors is linked to the development or exacerbation of psychotic features. It is also undetermined whether concurrent antipsychotic treatment provides any protective benefit against psychosis, especially in patients already being treated for psychotic symptoms.

Conclusions:

Our findings suggest that ropinirole may play a role in inducing or exacerbating psychosis and its associated features, although a number of confounding variables prevent the determination of a clear association and suggest that further investigation is warranted in controlled clinical trials.

The dopamine hypothesis of schizophrenia: version III--the final common pathway

The dopamine hypothesis of schizophrenia has been one of the most enduring ideas in psychiatry. Initially, the emphasis was on a role of hyperdopaminergia in the etiology of schizophrenia (version I), but it was subsequently reconceptualized to specify subcortical hyperdopaminergia with prefrontal hypodopaminergia (version II). However, these hypotheses focused too narrowly on dopamine itself, conflated psychosis and schizophrenia, and predated advances in the genetics, molecular biology, and imaging research in schizophrenia. Since version II, there have been over 6700 articles about dopamine and schizophrenia. We selectively review these data to provide an overview of the 5 critical streams of new evidence: neurochemical imaging studies, genetic evidence, findings on environmental risk factors, research into the extended phenotype, and animal studies. We synthesize this evidence into a new dopamine hypothesis of schizophrenia-version III: the final common pathway. This hypothesis seeks to be comprehensive in providing a framework that links risk factors, including pregnancy and obstetric complications, stress and trauma, drug use, and genes, to increased presynaptic striatal dopaminergic function. It explains how a complex array of pathological, positron emission tomography, magnetic resonance imaging, and other findings, such as frontotemporal structural and functional abnormalities and cognitive impairments, may converge neurochemically to cause psychosis through aberrant salience and lead to a diagnosis of schizophrenia. The hypothesis has one major implication for treatment approaches. Current treatments are acting downstream of the critical neurotransmitter abnormality. Future drug development and research into etiopathogenesis should focus on identifying and manipulating the upstream factors that converge on the dopaminergic funnel point.

Quetiapine improves visual hallucinations in Parkinson disease but not through normalization of sleep architecture: results from a double-blind clinical-polysomnography study

Polysomnographic studies of Parkinson's disease (PD) patients with visual hallucinations (VH) usually reveal short, fragmented rapid eye movement (REM) sleep, with lower sleep efficiency and reduced total REM sleep. Quetiapine has been demonstrated in open-label trials to be effective for the treatment of insomnia and VH in PD. To confirm quetiapine's efficacy in improving VH, and to determine whether the mechanism was due to its effect on REM sleep architecture, we performed a pilot, double-blind, placebo-controlled study. Sixteen PD patients experiencing VH were recruited. Eight patients were randomized to quetiapine and eight patients to placebo. Patients underwent pre- and post-treatment polysomnography. The Clinical Global Impression Scale (CGIS), Brief Psychiatric Rating Scale (BPRS), and Unified Parkinson Disease Rating Scale (UPDRS) motor subscale were obtained. There were no differences in baseline characteristics between the treatment arms except that the placebo group had more sleep in stage REM (74.7 min vs. 40.1 min; p < .001). Data were imputed for all patients who prematurely discontinued (four quetiapine and one placebo) in an intention-to-treat analysis. The average quetiapine dose was 58.3 mg/day. While there was no significant difference in the change in REM duration pre- vs. post-treatment in either arm, patients randomized to quetiapine improved on the CGIS (p = .03) and the hallucination item of the BPRS (p = .02). No difference was noted in the UPDRS motor scores. Despite the small sample, this is the first double-blind trial to show quetiapine's efficacy over placebo in controlling VH in the PD population. However, normalization of sleep architecture was not supported as the mechanism.