Cerebrospinal fluid findings in patients with psychotic symptoms-a retrospective analysis

An exploratory study of the damage markers NfL, GFAP, and t-Tau, in cerebrospinal fluid and other findings from a patient cohort enriched for suspected autoimmune psychiatric disease

There is growing evidence suggesting that immunological mechanisms play a significant role in the development of psychiatric symptoms in certain patient subgroups. However, the relationship between clinical red flags for suspected autoimmune psychiatric disease and signs of central nervous system (CNS) pathology (e.g., routine cerebrospinal fluid (CSF) alterations, CNS damage markers, neurophysiological or neuroimaging findings) has received limited attention. Here, we aimed to describe the prevalence and distribution of potential CNS pathologies in psychiatric patients in relation to clinical red flags for autoimmune psychiatric disease and psychiatric symptoms. CSF routine findings and CNS damage markers; neurofilament light chain protein (NfL), glial fibrillary acidic protein (GFAP) and total Tau (t-Tau), in CSF from 127 patients with psychiatric disease preselected for suspected immunological involvement were related to recently proposed clinical red flags, psychiatric features, and MRI and EEG findings. Twenty-one percent had abnormal routine CSF findings and 27% had elevated levels of CNS damage markers. Six percent had anti-neuronal antibodies in serum and 2% had these antibodies in the CSF. Sixty-six percent of patients examined with MRI (n = 88) had alterations, mostly atrophy or nonspecific white matter lesions. Twenty-seven percent of patients with EEG recordings (n = 70) had abnormal findings. Elevated NfL levels were associated with comorbid autoimmunity and affective dysregulation symptoms. Elevated t-Tau was associated with catatonia and higher ratings of agitation/hyperactivity. Elevated GFAP was associated with acute onset, atypical presentation, infectious prodrome, tics, depressive/anxiety symptom ratings and overall greater psychiatric symptom burden. In conclusion, preselection based on suspected autoimmune psychiatric disease identifies a population with a high prevalence of CSF alterations suggesting CNS pathology. Future studies should examine the value of these markers in predicting treatment responses.

The significance of cerebrospinal fluid analysis in the differential diagnosis of 564 psychiatric patients: Multiple sclerosis is more common than autoimmune-encephalitis

The analysis of cerebrospinal fluid (CSF) is an essential tool for the differential diagnosis of psychiatric disorders caused by autoimmune inflammation or infections. Clear guidelines for CSF analysis are limited and mainly available for schizophrenia and dementia. Thus, insights into CSF changes in psychiatric patients largely derive from research. We analyzed the clinical and CSF data of 564 psychiatric patients without pre-existing neurological diagnoses from March 1998 to April 2020. Primary aim was to detect previously undiagnosed neurological conditions as underlying cause for the psychiatric disorder. Following CSF analysis, 8 % of patients (47/564) were diagnosed with a neurological disorder. This was the case in 12.0 % (23/193) of patients with affective disorders, 7.2 % (19/262) of patients with schizophrenia, and 4.0 % (23/193) of patients with anxiety disorders. The predominant new diagnoses were multiple sclerosis (19/47) and autoimmune encephalitis (10/47). Abnormal CSF findings without any implications for further treatment were detected in 17.0 % (94/564) of patients. Our data indicates that CSF analysis in patients suffering from psychiatric disorders may uncover underlying organic causes, most commonly multiple sclerosis and autoimmune encephalitis. Our findings imply that the incorporation of CSF analysis in routine psychiatric assessments is potentially beneficial.

Nicotine Exposure in a Phencyclidine-Induced Mice Model of Schizophrenia: Sex-Selective Medial Prefrontal Cortex Protein Markers of the Combined Insults in Adolescent Mice

Tobacco misuse as a comorbidity of schizophrenia is frequently established during adolescence. However, comorbidity markers are still missing. Here, the method of label-free proteomics was used to identify deregulated proteins in the medial prefrontal cortex (prelimbic and infralimbic) of male and female mice modelled to schizophrenia with a history of nicotine exposure during adolescence. Phencyclidine (PCP), used to model schizophrenia (SCHZ), was combined with an established model of nicotine minipump infusions (NIC). The combined insults led to worse outcomes than each insult separately when considering the absolute number of deregulated proteins and that of exclusively deregulated ones. Partially shared Reactome pathways between sexes and between PCP, NIC and PCPNIC groups indicate functional overlaps. Distinctively, proteins differentially expressed exclusively in PCPNIC mice reveal unique effects associated with the comorbidity model. Interactome maps of these proteins identified sex-selective subnetworks, within which some proteins stood out: for females, peptidyl-prolyl cis-trans isomerase (Fkbp1a) and heat shock 70 kDa protein 1B (Hspa1b), both components of the oxidative stress subnetwork, and gamma-enolase (Eno2), a component of the energy metabolism subnetwork; and for males, amphiphysin (Amph), a component of the synaptic transmission subnetwork. These are proposed to be further investigated and validated as markers of the combined insult during adolescence.

Neuroimmune, clinical and treatment challenges in multiple sclerosis-related psychoses

In recent years, epidemiological and genetic studies have shown an association between autoimmune diseases and psychosis. The question arises whether patients with schizophrenia are more likely to develop multiple sclerosis (MS) later in life. It is well known that the immune system plays an important role in the etiopathogenesis of both disorders. Immune disturbances may be similar or very different in terms of different types of immune responses, disturbed myelination, and/or immunogenetic predispositions. A psychotic symptom may be a consequence of the MS diagnosis itself or a separate entity. In this review article, we discussed the timing of onset of psychotic symptoms and MS and whether the use of corticosteroids as therapy for acute relapses in MS is unfairly neglected in patients with psychiatric comorbidities. In addition, we discussed that the anti-inflammatory potential of antipsychotics could be useful and should be considered, especially in the treatment of psychosis that coexists with MS. Autoimmune disorders could precipitate psychotic symptoms, and in this context, autoimmune psychosis must be considered as a persistent symptomatology that requires continuous and specific treatment.

Cerebrospinal Fluid and Blood Biomarkers of Neuroinflammation and Blood-Brain Barrier in Psychotic Disorders and Individually Matched Healthy Controls

BACKGROUND AND HYPOTHESIS

Neuroinflammation and blood-brain barrier (BBB) dysfunction have been observed in patients with psychotic disorders. However, previous studies have mainly focused on selected patients and broad screenings of cerebrospinal fluid (CSF) of patients with recent onset psychosis compared to healthy controls are lacking.

STUDY DESIGN

We included 104 patients with recent onset psychotic disorder and 104 individually matched healthy controls. CSF and blood were analyzed for readily available markers assessing neuroinflammation and BBB dysfunction. Primary outcomes were CSF white blood cell count (WBC), total protein, IgG Index, and CSF/serum albumin ratio. Secondary outcomes included additional markers of inflammation and BBB, and analyses of association with clinical variables.

STUDY RESULTS

CSF/serum albumin ratio (Relative Mean Difference (MD): 1.11; 95%CI: 1.00-1.23; P = .044) and CSF/serum IgG ratio (MD: 1.17; 95%CI: 1.01-1.36; P = .036) was increased in patients compared to controls. A higher number of patients than controls had CSF WBC >3 cells/µl (seven vs. one, OR: 7.73, 95%CI: 1.33-146.49, P = .020), while WBC>5 cells/µl was found in two patients (1.9%) and no controls. Inpatients had higher serum WBC and neutrophil/lymphocyte ratio (all p-values for effect heterogeneity < .011). Mean CSF WBC (MD: 1.10; 95%CI: 0.97-1.26), protein (MD: 1.06; 95%CI: 0.98-1.15) and IgG index (MD: 1.05; 95%CI: 0.96-1.15) were not significantly elevated.

CONCLUSIONS

When comparing a broad group of patients with psychotic disorders with healthy controls, patients had increased BBB permeability, more patients had high CSF WBC levels, and inpatients had increased peripheral inflammation, consistent with the hypothesis of a subgroup of patients with increased activation of the immune system.

City Environment and Occurrence of Neural Autoantibodies in Psychiatric Patients

BACKGROUND

City living might lead to a higher risk of psychiatric disease, but to date there is no evidence of any correlation between an urban environment and the occurrence of neural autoantibodies in psychiatric disease. Our aim is to identify whether the number of patients with and without neural autoantibodies living in diverse rural and urban environments differ.

METHODS

We enrolled retrospectively a cohort of 167 psychiatric patients via a cross-sectional design from the Department of Psychiatry and Psychotherapy University Medical Center Göttingen and determined serum and/or CSF neural autoantibodies in them. The patients live in the German states of Lower Saxony, Thuringia, and Hessen. Their data were investigated in conjunction with the location of their primary residence. We categorized them into five different categories depending upon their primary residence: one rural and four different urban environments depending on their population numbers.

RESULTS

We identified 36 psychiatric patients with neural autoantibodies, and 131 psychiatric patients with none. In total, 24 psychiatric patients with neural autoantibodies were classified as sharing a possible, probable, or definitive autoimmune origin according to our recently set criteria. We observed as a non-significant trend that more psychiatric patients with neural autoantibodies and a probable or definitive autoimmune origin (45.8%) live in a major city with over 100,000 inhabitants than do psychiatric patients presenting no evidence of autoantibodies (26.4%). However, we identified no relevant differences between (1) psychiatric patients with and without neural autoantibodies or between (2) psychiatric patients with a possible, probable, or definitive autoimmune origin and those without such autoantibodies in relation to the diverse rural and urban environmental settings.

CONCLUSION

The inherently different aspects of rural and urban environments do not appear to be relevant in determining the frequency of neural autoantibodies in psychiatric patients in Lower Saxony, Thuringia, and Hessen in Germany. Furthermore, large-scale studies involving other states across Germany should be conducted to exclude any regional differences and to examine the tendency of a higher frequency in large cities of autoimmune-mediated psychiatric syndromes.

Cerebrospinal fluid abnormalities in first- and multi-episode schizophrenia-spectrum disorders: impact of clinical and demographical variables

Multiple lines of evidence indicate that immunological and inflammatory alterations contribute at least in a subgroup to the pathophysiology of schizophrenia. In this retrospective chart review, we investigated whether clinical factors contribute to altered cerebrospinal fluid (CSF) findings in schizophrenia-spectrum disorders. Clinical data from electronic medical records of patients with psychotic disorders (ICD-10: F20-F29) who received routine CSF diagnostics at the Department of Psychiatry and Psychotherapy, LMU Munich, Germany, were included. Chi² tests for dichotomous outcomes and independent t tests for continuous outcomes were used to compare differences between groups. A total of 331 patients were included in the analyses (43.2% female and 56.8% male). The mean age was 37.67 years (±15.58). The mean duration of illness was 71.96 months (±102.59). In all, 40% (128/320) were first-episode psychosis (FEP) patients and 60% (192/320) were multi-episode psychosis (MEP) patients. Elevated CSF protein levels were found in 19.8% and elevated CSF/serum albumin ratios (QAlb) in 29.4% of the cases. Pleocytosis was found in 6.1% of patients. MEP patients showed significantly higher mean QAlb compared with FEP patients (t(304.57) = -2.75, p = 0.006), which did not remain significant after correcting for age. QAlb elevation occurred more frequently in men (X2(1) = 14.76, p = <0.001). For treatment resistance, family history, and cMRI alterations, no significant differences in CSF-related outcomes were detected. Our work extends other retrospective cohorts confirming a relevant degree of CSF alterations in schizophrenia-spectrum disorders and shows the difficulty to relate these alterations to clinical and disease course trajectories. More research is needed to develop treatment response predictors from CSF analyses.

Cerebrospinal fluid test results and associations with subsequent mental disorders, neurological diseases, and CNS infections: A population-based cohort study

BACKGROUND

Cerebrospinal fluid (CSF) immune alterations have been associated with mental disorders, neurological disease, and CNS infections; however, comprehensive large-scale longitudinal CSF studies are lacking.

METHODS

By using the Clinical Laboratory Information System (LABKA) Research Database in the Central Denmark Region (1994-2012), we included 15,030 individuals tested for CSF WBC, CSF/serum albumin ratio, IgG index, total protein, albumin, or IgG with follow-up for the risk of mental disorders, psychotropic prescriptions, neurological diseases, or CNS infections, estimated by Cox regression.

RESULTS

Among individuals receiving a mental disorder diagnosis (N = 1,147) after a CSF test, 30·0% had an abnormal CSF test result, while for those with a neurological disease (N = 3,201), 39·9% had abnormal test results, and among individuals with CNS infections (N = 1,276), 73·0% had abnormal test results. Individuals with abnormal CSF test results had an increased risk of mental disorders (HR = 3·20; 95%CI = 2·86-3·59), neurological diseases (HR = 12·40; 95%CI = 11·65-13·20), and CNS infections (HR = 338·59; 95%CI = 299·06-383·35) compared to individuals not registered with a CSF test. However, the risk of mental disorders was higher (P < 0·001) after CSF test results within the normal range (HR = 4·45; 95%CI = 4·08-4·86), whereas for neurological diseases (HR = 9·72; 95%CI = 9·19-10·29) and CNS infections (HR = 55·17; 95%CI = 47·12-64·60), the risk was highest after abnormal CSF test results (all P < 0·001). The risk of organic mental disorders tended to be highest in individuals with abnormal CSF test results (HR = 19·30; 95%CI = 13·44-27·71) even though not significantly different from the risk in the group of individuals with CSF test results in the normal range (HR = 13·55; 95%CI = 9·36-19·60) (P ≥ 0·05). Abnormal CSF test results were associated with an elevated risk of psychotropic prescriptions (HR = 3·91; 95%CI = 3·66-4·18), as were CSF test results within the normal range (HR = 4·26; 95%CI = 4·03-4·51) (P < 0·05).

CONCLUSIONS

Immunological CSF abnormalities are associated with an increased risk of mental disorders, neurological disease, and particularly CNS infections; however, the included CSF parameters were not specific for mental disorders and the relevant CSF biomarkers in psychiatry are yet to be discovered.

Cerebrospinal Fluid Pathologies in Schizophrenia-Spectrum Disorder-A Retrospective Chart Review

BACKGROUND

The role of inflammatory processes in the etiology of schizophrenia is increasingly being investigated. A link between psychosis and inflammation measured with different biomarkers has been reported in the literature and needs to be further explored. To investigate the presence of inflammatory biomarkers in first-episode psychosis (FEP) we analyzed the largest available FEP cohort to date regarding routine CSF and blood diagnostics.

METHODS

We report a retrospective analysis of clinical data from all inpatients that were admitted to our tertiary care hospital with a ICD-10 diagnosis of F2x (schizophrenia-spectrum) between January 1, 2008 and August 1, 2018 and underwent a lumbar puncture.

RESULTS

A total of n = 314 FEP patients were included in our sample. 42.7% patients (134/314) showed cerebrospinal fluid (CSF) alterations. Oligoclonal bands in the CSF were present in 21.8% of patients (67/307) with 12.4% (27/217) of patients presenting OCBs type 2 or 3. 15.8% (49/310) of our cohort revealed signs of blood-brain-barrier (BBB) dysfunction with increased albumin ratios. Mean serum CRP levels were 2.4 mg/l (SD = 9.5). CRP elevation was present in 116/280 cases (41.4%).

CONCLUSIONS

This large retrospective analysis on FEP cohort greatly enriches the clinical data available on this population and contributes to the discussion around inflammation in psychosis. Of note, even though several inflammatory alterations were found both in CSF and in blood tests, we found no evidence for a significant relationship between peripheral inflammation and inflammatory CSF. Furthermore, no significant relationship between CSF alterations and peripheral inflammation measured with CRP could be established.

Alteration of NMDA receptor trafficking as a cellular hallmark of psychosis

A dysfunction of the glutamatergic transmission, especially of the NMDA receptor (NMDAR), constitutes one of the main biological substrate of psychotic disorders, such as schizophrenia. The NMDAR signaling hypofunction, through genetic and/or environmental insults, would cause a neurodevelopmental myriad of molecular, cellular, and network alterations that persist throughout life. Yet, the mechanisms underpinning NMDAR dysfunctions remain elusive. Here, we compared the membrane trafficking of NMDAR in three gold-standard models of schizophrenia, i.e., patient's cerebrospinal fluids, genetic manipulations of susceptibility genes, and prenatal developmental alterations. Using a combination of single nanoparticle tracking, electrophysiological, biochemical, and behavioral approaches in rodents, we identified that the NMDAR trafficking in hippocampal neurons was consistently altered in all these different models. Artificial manipulations of the NMDAR surface dynamics with competing ligands or antibody-induced receptor cross-link in the developing rat brain were sufficient to regulate the adult acoustic startle reflex and compensate for an early pathological challenge. Collectively, we show that the NMDAR trafficking is markedly altered in all clinically relevant models of psychosis, opening new avenues of therapeutical strategies.

Cerebrospinal fluid flow cytometry distinguishes psychosis spectrum disorders from differential diagnoses

Psychotic disorders are common and disabling mental conditions. The relative importance of immune-related mechanisms in psychotic disorders remains subject of debate. Here, we present a large-scale retrospective study of blood and cerebrospinal fluid (CSF) immune cell profiles of psychosis spectrum patients. We performed basic CSF analysis and multi-dimensional flow cytometry of CSF and blood cells from 59 patients with primary psychotic disorders (F20, F22, F23, and F25) in comparison to inflammatory (49 RRMS and 16 NMDARE patients) and non-inflammatory controls (52 IIH patients). We replicated the known expansion of monocytes in the blood of psychosis spectrum patients, that we identified to preferentially affect classical monocytes. In the CSF, we found a relative shift from lymphocytes to monocytes, increased protein levels, and evidence of blood-brain barrier disruption in psychosis. In fact, these CSF features confidently distinguished autoimmune encephalitis from psychosis despite similar (initial) clinical features. We then constructed machine learning models incorporating blood and CSF parameters and demonstrated their superior ability to differentiate psychosis from non-inflammatory controls compared to individual parameters. Multi-dimensional and multi-compartment immune cell signatures can thus support the diagnosis of psychosis spectrum disorders with the potential to accelerate diagnosis and initiation of therapy.