Brain MRI in neuropsychiatric lupus: associations with the 1999 ACR case definitions

VPS13C and STING expression in neuropsychiatric systemic lupus erythematosus: unveiling an unbreached territory

OBJECTIVES

To measure the expression level of the vacuolar protein sorting 13 (VPS13) gene and stimulator of interferon genes (STING) in patients with SLE with and without reported neuropsychiatric symptoms to establish their possible role in the pathogenesis of neuropsychiatric SLE (NPSLE).

METHODS

This study included 100 subjects: 50 patients diagnosed with SLE and 50 age-matched and sex-matched healthy participants as the control group. The patients with SLE were further subdivided into NPSLE and non-NPSLE groups. All the subjects underwent rheumatological, neurological and psychological evaluation, MRI, VPS13C gene and STING expression assessment via quantitative real-time PCR.

RESULTS

Seventy-eight per cent of the SLE group were classified as non-NPSLE, and 22% were classified as NPSLE. Positive MRI results were found in 55% of the patients with NPSLE and 7.7% of the patients without NPSLE.VPS13C expression levels were decreased in the patients with SLE compared with the control (p<0.001), while STING expression levels showed higher levels in the patients in comparison with the control (p<0.001). Both markers showed significant differences between the MRI-positive and MRI-negative groups.At a cut-off value of 0.225 for the VPS13C assessment and a cut-off value of 3.15 for STING expression, both markers were able to distinguish patients with NPSLE from those who were non-NPSLE; however, VPS13C performed better.

CONCLUSION

The VPS13C expression levels were decreased in patients with NPSLE compared with patients without NPSLE, while STING expression levels showed higher levels in NPSLE. Both were associated with the MRI findings. To distinguish patients with NPSLE from those without it, the VPS13C assessment performed better.

Chorea as an initial and solitary manifestation of systemic lupus erythematosus with antiphospholipid syndrome in an elderly man

Chorea can be an initial manifestation of systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS). It has been mostly described in younger female adults in association with other manifestations of SLE. When chorea appears as an initial and only manifestation in SLE/APS patients, the establishment of the correct diagnosis is difficult, and it may be initially attributed to a more common aetiology. Here we report an elderly man who presented with a new onset of right-sided chorea without other clinical manifestations of SLE/APS. He started on steroids a year later, however, there was no improvement. His chorea was symptomatically managed along with aspirin, and hydroxychloroquine as he refused to be on additional immunosuppression. Anticoagulation was relatively contraindicated, and also not favoured by this patient; therefore, aspirin was initiated. Even in elderly patients, once the common etiologies of chorea have been worked up, we suggest doing a rheumatological evaluation. Early diagnosis and prompt treatment can prevent persistent neurological abnormality.

Clinical Reasoning: A 40-Year-Old Woman Presenting With Encephalopathy and Paraparesis

Patients with acute to subacute multifocal neurologic abnormalities often have a unique presentation, and their diagnosis and management can be challenging. We present the case of a 40-year-old patient who presented with a 4-day history of confusion, bradyphrenia, right facial droop, bilateral lower limb weakness, urinary incontinence, and hypothermia. This case highlights the diagnostic approach to patients with subacute multifocal neurologic abnormalities, the importance of considering coexisting systemic illnesses in the diagnosis, and their management. Readers will explore the diagnostic steps our group has considered to reach our final diagnosis and the importance of management for our leading diagnosis.

The conundrum of neuropsychiatric systemic lupus erythematosus: Current and novel approaches to diagnosis

Recognising neuropsychiatric involvement by systemic lupus erythematosus (SLE) is of growing importance, however many barriers to this exist at multiple levels of our currently available diagnostic algorithms that may ultimately delay its diagnosis and subsequent treatment. The heterogeneous and non-specific clinical syndromes, serological and cerebrospinal fluid (CSF) markers and neuroimaging findings that often do not mirror disease activity, highlight important research gaps in the diagnosis of neuropsychiatric SLE (NPSLE). Formal neuropsychological assessments or the more accessible screening metrics may also help improve objective recognition of cognitive or mood disorders. Novel serum and CSF markers, including autoantibodies, cytokines and chemokines have also shown increasing utility as part of diagnosis and monitoring, as well as in distinguishing NPSLE from SLE patients without SLE-related neuropsychiatric manifestations. Novel neuroimaging studies also expand upon our existing strategy by quantifying parameters that indicate microarchitectural integrity or provide an assessment of neuronal function. Some of these novel markers have shown associations with specific neuropsychiatric syndromes, suggesting that future research move away from considering NPSLE as a single entity but rather into its individually recognized neuropsychiatric manifestations. Nevertheless, it is likely that a composite panel of these investigations will be needed to better address the gaps impeding recognition of neuropsychiatric involvement by SLE.

Case Report: Rapid Progression of Cognitive Dysfunction as an Initial Feature of Systemic Lupus Erythematosus With Leukoencephalopathy: A Case Report and Literature Review

Neuropsychiatric systemic lupus erythematosus (NPSLE) has been considered to have high morbidity and mortality. Thus, earlier recognition and treatment are of great importance. However, the rapid progression of cognitive dysfunction with leukoencephalopathy as an initial presentation in SLE is rarely described. We report a case in which an elderly man experienced rapidly progressive cognitive impairment with bilateral, symmetric, and diffuse leukoencephalopathy with lasting diffusion-weighted image hyperintensity. An immunological workup showed low complement levels and positivity for antinuclear antibody -speckle and Coombs tests in the patient's serum samples. He had an appropriate improvement in cognitive function after receiving a combination of various immunotherapies. Long-term follow-up showed clinical improvement, including rheumatological labs and neuroimaging. A review of the literature on NPSLE with leukoencephalopathy and a summary of all reported cases to date are also presented. Our case indicated that isolated leukoencephalopathy in NPSLE, as an indicator of severe NPSLE, can be recognized early. Immunotherapy is warranted given the possibility of clinical improvement.

Cerebral Microstructure Analysis by Diffusion-Based MRI in Systemic Lupus Erythematosus: Lessons Learned and Research Directions

Diffusion-based magnetic resonance imaging (MRI) studies, namely diffusion-weighted imaging (DWI) and diffusion-tensor imaging (DTI), have been performed in the context of systemic lupus erythematosus (SLE), either with or without neuropsychiatric (NP) involvement, to deepen cerebral microstructure alterations. These techniques permit the measurement of the variations in random movement of water molecules in tissues, enabling their microarchitecture analysis. While DWI is recommended as part of the initial MRI assessment of SLE patients suspected for NP involvement, DTI is not routinely part of the instrumental evaluation for clinical purposes, and it has been mainly used for research. DWI and DTI studies revealed less restricted movement of water molecules inside cerebral white matter (WM), expression of a global loss of WM density, occurring in the context of SLE, prevalently, but not exclusively, in case of NP involvement. More advanced studies have combined DTI with other quantitative MRI techniques, to further characterize disease pathogenesis, while brain connectomes analysis revealed structural WM network disruption. In this narrative review, the authors provide a summary of the evidence regarding cerebral microstructure analysis by DWI and DTI studies in SLE, focusing on lessons learned and future research perspectives.

Headache in patients with systemic lupus erythematosus: characteristics, brain MRI patterns, and impact

Background

The prevalence of primary headache in patients with systemic lupus erythematosus (SLE) varies widely and whether it should be attributed to neurological involvement is controversial. We aimed to investigate the prevalence and characteristics of headache in SLE patients, describe its association with disease-related variables and brain imaging, and explore its impact on life.

Results

The overall prevalence of headache was 54.4%, and migraine was the most common type among headache sufferers (48.4%). Headache severity (VAS) and impact (HIT-6) correlated with SLEDAI-2K (P = 0.019 and P < 0.001, respectively) as well as with each other (P = 0.006). Brain imaging abnormalities were found in 25.8%, with white-matter hyperintensities (WMH) being the most frequent pathology. Musculoskeletal manifestations, positive anti-phospholipid (aPL) antibodies, and SLEDAI score ≥ 13.5 were identified as predictors of headache.

Conclusion

Primary headache, especially migraine, is a common feature of patients with SLE, and its presence is associated with negative impact on quality of life. Musculoskeletal features, aPL positivity, and overall disease activity appear to predict primary headache in SLE.

Quantitative MRI adds to neuropsychiatric lupus diagnostics

OBJECTIVE

Attributing neuropsychiatric manifestations to SLE is often challenging. Brain white matter lesions are frequent in SLE at MRI, but their diagnostic role is unclear. Here, we assessed whether white matter lesions count, volume and distribution measurement can help in the diagnosis of neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Brain dual-echo and 3D T1-weighted sequences were acquired from 32 patients with SLE and 32 healthy controls with a 3 T-scanner and employed to derive T2-hyperintense lesion volume (T2LV), number (T2LN) and probability maps (LPM) using a semi-automatic local thresholding segmentation technique. NPSLE was classified as per the ACR nomenclature, the Italian Society for Rheumatology algorithm and by clinical impression. Clinical descriptors including the SLE International Collaborating Clinics/ACR damage index (SDI) were also recorded.

RESULTS

Higher T2LV were observed in SLE vs healthy controls (P < 0.001) and in NPSLE vs other SLE (P =0.006). Patients with NPSLE also had higher T2LN (P =0.003) compared with other SLE. In SLE, T2LPM revealed a high prevalence of lesions in the splenium of the corpus callosum, right superior longitudinal fasciculus and right corona radiata. T2LV and T2LN correlated with SLE duration (rho = 0.606; P <0.001 and rho = 0.483; P =0.005, respectively) and age (rho = 0.478; P =0.006 and rho = 0.362; P = 0.042, respectively). T2LV also correlated with SDI (rho = 0.352; P =0.048). SLE patients with fatigue had lower T2LN (P =0.038) compared with patients without fatigue. Thresholds of T2LV ≥ 0.423 cm3 or of T2LN ≥ 12 were associated with definite NPSLE and improved the classification of patients with possible NPSLE per clinical impression.

CONCLUSION

Brain white matter lesions (WML) quantitation adds to NPSLE diagnostics.

Neuroimaging findings in rheumatologic disorders

Patients with rheumatological diseases may present with neurological manifestations of peripheral and/or central nervous system (CNS). Symptoms may be related to underlying rheumatological disease or CNS effects of immune-modulating drugs. Early diagnosis and therapy may help prevent serious complications. Magnetic resonance imaging (MRI), given its excellent soft tissue details, is the preferred imaging modality when evaluating patients with rheumatological disease and suspected CNS involvement. We present a review of the neuroimaging manifestations of various rheumatic diseases with emphasis on the imaging findings on MRI.

Central Nervous System Systemic Lupus Erythematosus (CNS-SLE) Vasculitis Mimicking Lewy Body Dementia: A Case Report Emphasizing the Role of Imaging With an Analysis of 33 Comparable Cases From the Scientific Literature

INTRODUCTION

Neuropsychiatric symptoms occur in 30% to 40% of patients living with systemic lupus erythematosus (SLE). Brain imaging may play a pivotal role in determining the etiology as it did for the case presented here.

METHODS

A new case of central nervous system (CNS) SLE is presented along with an analysis of 33 comparable cases from the scientific literature.

RESULTS

A 70-year-old female with subacute cutaneous lupus presented to a university-based geropsychiatry program after 1 year of benign visual hallucinations and several months of shuffling gait, recurrent falls, and forgetfulness. These symptoms were highly suggestive of Lewy body dementia; however, the patient's history of basal ganglia infarct, cognitive testing demonstrating inattention and executive dysfunction, and follow-up brain imaging, which did not reveal acute findings, aligned with cerebral pathology previously attributed to vasculitis and supported the diagnosis of subcortical dementia due to SLE-CNS vasculitis. Oral prednisone 20 mg daily resolved her symptoms. Over the next 19 months, her prednisone was tapered completely and her symptoms did not return. A systematic literature search identified 33 comparable cases.

CONCLUSION

An analysis of previously published cases suggests that extending the duration of the prednisone taper beyond 1 year may decrease the risk of later occurring neuropsychiatric symptoms in this patient population.

Is serum TWEAK a useful biomarker of neuropsychiatric systemic lupus erythematosus?

The aim of this study was to determine the role of the tumor necrosis factor like weak inducer of apoptosis (TWEAK) as a serum biomarker of neuropsychiatric involvement in systemic lupus erythematosus (NPSLE). Levels of TWEAK levels were measured in sera of 92 patients with systemic lupus erythematosus (SLE), including 28 patients with neuropsychiatric lupus, and in 59 healthy controls using ELISA. All SLE patients underwent rheumatological, neurological and psychiatric assessment. We found no significant differences in TWEAK levels, between SLE patients and the healthy controls (p=0.2411). Similarly, no difference was observed between subgroup of NPSLE and healthy controls (p=0.7658). The mean SLE disease activity (SLEDAI) was 13.25. No correlations between TWEAK levels with disease activity (SLEDAI, r=0.2113, p=0.2805) or the most common NPSLE manifestations such as headache (r=0.2079), seizures (r=0.1101), cerebrovascular disease (r= 0.2347), cognitive dysfunction (r=0.1597) and anxiety (r=0.1397) were observed. Our data do not support the use of serum TWEAK as a discriminating biomarker for NPSLE. The role of the TWEAK in NPSLE remains to be investigated.

From Systemic Inflammation to Neuroinflammation: The Case of Neurolupus

It took decades to arrive at the general consensus dismissing the notion that the immune system is independent of the central nervous system. In the case of uncontrolled systemic inflammation, the relationship between the two systems is thrown off balance and results in cognitive and emotional impairment. It is specifically true for autoimmune pathologies where the central nervous system is affected as a result of systemic inflammation. Along with boosting circulating cytokine levels, systemic inflammation can lead to aberrant brain-resident immune cell activation, leakage of the blood⁻brain barrier, and the production of circulating antibodies that cross-react with brain antigens. One of the most disabling autoimmune pathologies known to have an effect on the central nervous system secondary to the systemic disease is systemic lupus erythematosus. Its neuropsychiatric expression has been extensively studied in lupus-like disease murine models that develop an autoimmunity-associated behavioral syndrome. These models are very useful for studying how the peripheral immune system and systemic inflammation can influence brain functions. In this review, we summarize the experimental data reported on murine models developing autoimmune diseases and systemic inflammation, and we explore the underlying mechanisms explaining how systemic inflammation can result in behavioral deficits, with a special focus on in vivo neuroimaging techniques.

Correlation of neurocognitive function and brain lesion load on magnetic resonance imaging in systemic lupus erythematosus

Neurocognitive dysfunction and brain injury on magnetic resonance imaging (MRI) are common in patients with systemic lupus erythematosus (SLE) and are associated with increased morbidity and mortality. However, brain MRI is expensive, is restricted by payers, and requires high expertise. Neurocognitive assessment is an easily available, safe, and inexpensive clinical tool that may select patients needing brain MRI. In this cross-sectional and controlled study, 76 SLE patients (69 women, age 37 ± 12 years) and 26 age and gender-matched healthy subjects (22 women, age 34 ± 11 years) underwent assessment of attention, memory, processing speed, executive function, motor function, and global neurocognitive function. All subjects underwent brain MRI with T1-weighted, fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging. Hemispheric and whole brain lesion load in cm³ were determined using semi-automated methods. Neurocognitive z-scores in all clinical domains were significantly lower and whole brain and right and left hemispheres brain lesion load were significantly greater in patients than in controls (all p ≤ 0.02). There was significant correlation between neurocognitive z-scores in all domains and whole brain lesion load: processing speed (r = - 0.46; p < 0.0001), attention (r = - 0.42; p < 0.001), memory (r = - 0.40; p = 0.0004), executive function (r = - 0.25; p = 0.03), motor function (r = - 0.25; p = 0.05), and global neurocognitive function (r = - 0.38; p = 0.006). Similar correlations were found for brain hemisphere lesion loads (all p ≤ 0.05). These correlations were strengthened when adjusted for glucocorticoid therapy and SLE disease activity index. Finally, global neurocognitive z-score and erythrosedimentation rate were the only independent predictors of whole brain lesion load (both p ≤ 0.007). Neurocognitive measures and brain lesion load are worse in SLE patients than in controls. In SLE patients, neurocognitive z-scores correlate negatively with and independently predict brain lesion load. Therefore, neurocognitive testing may be an effective clinical tool to select patients needing brain MRI.

Magnetic resonance imaging in neuropsychiatric systemic lupus erythematosus: current state of the art and novel approaches

Systemic lupus erythematosus is a chronic, inflammatory, immune-mediated disease affecting 0.1% of the general population. Neuropsychiatric manifestations in systemic lupus erythematosus have been more frequently recognized and reported in recent years, occurring in up to 75% of patients during the disease course. Magnetic resonance imaging is known to be a useful tool for the detection of structural brain abnormalities in neuropsychiatric systemic lupus erythematosus patients because of the excellent soft-tissue contrast observed with MRI and the ability to acquire multiplanar images. In addition to conventional magnetic resonance imaging techniques to evaluate the presence of atrophy and white matter lesions, several different magnetic resonance imaging techniques have been used to identify microstructural or functional abnormalities. This review will highlight different magnetic resonance imaging techniques, including the advanced magnetic resonance imaging methods used to determine central nervous system involvement in systemic lupus erythematosus.

Elevated serum MFG-E8 level is possibly associated with the presence of high-intensity cerebral lesions on magnetic resonance imaging in patients with systemic lupus erythematosus

Human milk fat globule-EGF factor 8 (MFG-E8), also known as lactadherin, is a secreted glycoprotein that plays essential roles in the clearance of apoptotic cells and angiogenesis. It has been reported that serum MFG-E8 levels are higher in systemic lupus erythematosus (SLE) patients compared with in healthy controls; however, a previous study reported no correlation between serum MFG-E8 levels and SLE disease activity. The objective of this study was to assess serum MFG-E8 levels and their clinical associations in patients with SLE. Serum MFG-E8 levels in 49 Japanese patients with SLE, eight with cutaneous LE, and 28 healthy controls were examined. Serum MFG-E8 levels in SLE patients were significantly higher than those in cutaneous LE patients and healthy individuals. In addition, serum MFG-E8 levels were positively correlated with the SLE Disease Activity Index score, which reflects the disease activity of SLE. Notably, the frequency of the presence of high-intensity cerebral lesions on MRI in the SLE patients with elevated serum MFG-E8 levels was significantly higher than that in SLE patients with normal serum MFG-E8 levels. These findings suggest that elevated serum MFG-E8 levels may be associated with cerebrovascular diseases or neuropsychiatric SLE in patients with SLE, and that the measurement of serum MFG-E8 levels in SLE patients is useful for risk stratification of cerebrovascular disease or cerebrovascular disease-related neuropsychiatric SLE.

Neurological Complications of Rheumatic Disease

Rheumatic disease represents a broad spectrum of systemic conditions manifested by multisystem involvement and mediated by autoimmunity and inflammation. Their neurological complications may occur at any point in the disease process and are diagnostically challenging. For years central nervous system (CNS) was considered as a system uniquely protected from effects of the immune system because of the blood-brain barrier. Indeed, under physiological conditions immune access to CNS is tightly regulated. Over the past decade, new scientific discoveries highlighted pathways by which immune and neurological systems interact, including a variety of mechanisms controlling permeability of blood-brain barrier, and specific roles that CD4⁺ and CD8⁺ T-lymphocytes play in initiation of specific adaptive immune response to neural specific antigens. This leads to release of proinflammatory cytokines (interleukin 1, interleukin 6, and tumor necrosis factor alpha). In addition, B-cells involved in CNS inflammation produce antibodies against membrane bound and soluble antigens. This article describes specific neurological manifestations of the most common autoimmune rheumatic disorders.

Neuropsychiatric Lupus in clinical practice

ABSTRACT Systemic lupus erythematosus (SLE) is a chronic autoimmune disease involving multiple organs, characterized by the production of autoantibodies and the development of tissue injury. The etiology of SLE is partially known, involving multiple genetic and environmental factors. As many as 50% of patients with SLE have neurological involvement during the course of their disease. Neurological manifestations are associated with impaired quality of life, and high morbidity and mortality rates. Nineteen neuropsychiatric syndromes have been identified associated with SLE, and can be divided into central and peripheral manifestations. This article reviews major neuropsychiatric manifestations in patients with SLE and discusses their clinical features, radiological findings and treatment options.

Brain morphology and cortical thickness variations in systemic lupus erythematosus patients: Differences among neurological, psychiatric, and nonneuropsychiatric manifestations

PURPOSE

To determine whether systemic lupus erythematosus (SLE) affecting subcortical white matter volumes, deep gray matter volumes, and cortical thickness differ between groups of SLE patients with psychiatric (P-SLE), neurological (N-SLE), or nonneuropsychiatric (non-NPSLE) presentations.

MATERIALS AND METHODS

Sixty-seven participants were divided into three groups (P-SLE [n = 19], N-SLE [n = 12], and non-NPSLE [n = 36]) and examined with a 1.5T MRI scanner. The images were segmented in FreeSurfer software into volumetric and cortical thickness measures using T₁ 3D magnetization prepared rapid gradient echo-weighted imaging. For comparative analyses of volume, multivariate analyses of covariance (MANCOVA) were applied followed by Bonferroni post-hoc tests, with age as a covariate. For cortical thickness analyses, the groups were compared with the Query Design Estimate Contrast tool adjusted for age.

RESULTS

Globus pallidus volumes in both left (P ≤ 0.01) and right (P ≤ 0.05) hemispheres were larger in the N-SLE group than in the non-NPSLE group, and the left GP volume was greater in the N-SLE group than in the P-SLE group (P ≤ 0.05) (MANCOVA, post-hoc Bonferroni). The P-SLE group presented with thinning of cortical areas relative to the N-SLE (predominantly in the left parietal and right frontal and parietal regions) (P ≤ 0.05) and non-NPSLE (predominantly in parietal and occipital regions) (P ≤ 0.05) groups, whereas the N-SLE group presented with thickening of cortical areas (mostly right frontal and left parietal regions) relative to the non-NPSLE (P ≤ 0.05) and P-SLE groups.

CONCLUSION

N-SLE patients had greater local volumes and cortical thicknesses than the other two groups, whereas P-SLE patients presented with decreased volumes and cortical thinning. These findings provide evidence of distinct neuroanatomical abnormalities in neurological versus psychiatric manifestations of SLE.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;46:150-158.

The diagnosis and clinical management of the neuropsychiatric manifestations of lupus

Neuropsychiatric (NP) involvement in Systemic Lupus Erythematosus (SLE), can be a severe and troubling manifestation of the disease that heavily impacts patient's health, quality of life and disease outcome. It is one of the most complex expressions of SLE which can affect central, peripheral and autonomous nervous system. Complex interrelated pathogenetic mechanisms, including genetic factors, vasculopathy, vascular occlusion, neuroendocrine-immune imbalance, tissue and neuronal damage mediated by autoantibodies, inflammatory mediators, blood brain barrier dysfunction and direct neuronal cell death can be all involved. About NPSLE a number of issues are still matter of debate: from classification and burden of NPSLE to attribution and diagnosis. The role of neuroimaging and new methods of investigation still remain pivotal and rapidly evolving as well as is the increasing knowledge in the pathogenesis. Overall, two main pathogenetic pathways have been recognized yielding different clinical phenotypes: a predominant ischemic-vascular one involving large and small blood vessels, mediated by aPL, immune complexes and leuko-agglutination which it is manifested with more frequent focal NP clinical pictures and a predominantly inflammatory-neurotoxic one mediated by complement activation, increased permeability of the BBB, intrathecal migration of autoantibodies, local production of immune complexes and pro-inflammatory cytokines and other inflammatory mediators usually appearing as diffuse NP manifestations. In the attempt to depict a journey throughout NPSLE from diagnosis to a reasoned therapeutic approach, classification, epidemiology, attribution, risk factors, diagnostic challenges, neuroimaging techniques and pathogenesis will be considered in this narrative review based on the most relevant and recent published data.

Neuropsychiatric lupus: a mosaic of clinical presentations

Neuropsychiatric symptoms affect nearly half of the patients with systemic lupus erythematosus; however, the effect on disease severity, quality of life, and prognosis is tremendous. Symptoms of neuropsychiatric systemic lupus erythematosus may range from mild diffuse ones, to acute life threatening events. Although the underlying mechanisms are still largely unraveled, several pathogenic pathways are identified, such as antibody-mediated neurotoxicity, vasculopathy due to anti-phospholipid antibodies and other mechanisms, and cytokine-induced neurotoxicity. In the current review, we describe the old and the new regarding epidemiology, pathophysiology, diagnosis, and management of neuropsychiatric systemic lupus erythematosus. The possible link between neuropsychiatric symptoms and specific mechanisms may help to facilitate our understanding of the disease in the future, thus allowing for better treatment strategies.