NMDAR autoantibodies in psychiatric disease - An immunopsychiatric continuum and potential predisposition for disease pathogenesis

Time moving 100-fold slower: time distortion as a diagnostic clue in anti-NMDA receptor encephalitis

BACKGROUND

The primary symptoms in the early stages of anti-NMDA receptor encephalitis are psychiatric manifestations, making it difficult to distinguish from psychiatric disorders. While anti-NMDA receptor encephalitis requires a completely different treatment approach, the specific psychiatric features of the condition remain poorly identified. Although previous studies have suggested that altered perceptions may be characteristic, few case reports focus on altered perceptions of time or time distortion, a phenomenon closely linked to NMDA receptor dysfunction as seen in individuals using NMDA receptor inhibitors like ketamine and phencyclidine. In this report, we describe two cases of anti-NMDA receptor encephalitis manifesting pronounced time distortion in its early stages, which may serve as diagnostic clues for the early diagnosis and treatment of this potentially lethal condition.

CASE PRESENTATIONS

Two cases of Anti-NMDA receptor encephalitis, both marked by significant time distortion in the early stages and showing near-complete recovery with immunotherapy, are presented in detail. In both cases, time distortion was the predominant symptom among the psychiatric manifestations. Case 1: A middle-aged man experienced a pronounced perception of time moving 100 times slower in the early stages, accompanied by feelings of detachment and auditory abnormalities. This time distortion persisted for over a year, even after other symptoms had fully resolved. Case 2: A young woman reported that time seemed to move two to three times slower in the early stages. Although she did not initially mention time distortion, she confirmed it when specifically questioned.

CONCLUSIONS

Our report suggests that time distortion, particularly the perception of time moving slowly, can be a distinguishing feature in the early stages of anti-NMDA receptor encephalitis. This unique characteristic, especially when occurring independently of other symptoms, is rare as a primary and isolated symptom in other conditions, making it useful for differentiation from time distortion in other psychiatric disorders. Additionally, since some patients may not spontaneously report time distortion, actively assessing this symptom during early evaluation could help improve diagnostic accuracy.

Neuropsychiatric drug development: Perspectives on the current landscape, opportunities and potential future directions

Mental health represents a major challenge to our societies. One key difficulty associated with neuropsychiatric drug development is the lack of connection between the underlying biology and the disease. Nevertheless, there is growing optimism in this field with recent drug approvals (the first in decades) and renewed interest from pharmaceutical companies and investors. Here we review some of the most promising drug discovery and development endeavors currently deployed by industry. We also present elements illustrating the renewed interest from key stakeholders in neuropsychiatric drug development and provide potential future directions in this field.

Clinical symptoms and psychosocial functioning in patients with schizophrenia spectrum disorders testing seropositive for anti-NMDAR antibodies: a case-control comparison with patients testing negative

BACKGROUND

Antibodies against the N-methyl-D-aspartate receptor (NMDAR) have been described in the serum of people with schizophrenia spectrum disorders (schizophrenia). However, the prevalence and clinical relevance of these antibodies in schizophrenia is unclear. This knowledge gap includes the possibility of such antibodies being associated with a distinct clinical profile, which in turn might warrant a distinct treatment approach. We aimed to assess the seroprevalence of anti-NMDAR antibodies in schizophrenia, and compare symptoms and psychosocial functioning between patients with schizophrenia who were seropositive and seronegative for these antibodies.

METHODS

In this case-control comparison, by combining new and existing studies, we included patients diagnosed with schizophrenia from four independent cohorts for whom anti-NMDAR serostatus had been assessed (or could be assessed by us) with live cell-based assays. Included cohorts were from the EULAST study (a trial conducted across 15 European countries and Israel), the OPTiMiSE study (an interventional study in Europe), and the PPiP1 and PPiP2 studies (conducted in the UK). Patients from these cohorts were analysed if they had complete Positive and Negative Syndrome Scale (PANSS) data. No participant had been diagnosed with autoimmune encephalitis or received treatment for this condition. After calculating the prevalence of serum anti-NMDAR antibodies, we examined possible differences in PANSS scores (negative, positive, and general symptom subscales, and total score) between anti-NMDAR-seropositive and anti-NMDAR-seronegative patients. Psychosocial functioning as measured by Personal Social Performance (PSP) score was also compared. All analyses were exploratory and no adjustment was done for multiple testing. People with lived experience were not involved in the conduct of this study.

FINDINGS

We collected individual patient data from 1114 patients with schizophrenia across the four cohorts. The study population had a mean age of 28·6 years (SD 7·6) and comprised 382 (34·3%) women and 732 (65·7%) men, including patients of White (929 [83·4%]), Asian (54 [4·8%]), Black (68 [6·1%]), and other (62 [5·6%]) ethnicities. Overall, 41 (3·7%) participants (range 3·1-4·0% across cohorts) tested positive for serum anti-NMDAR antibodies. Lower symptom severity on the negative symptoms PANSS subscale was observed for anti-NMDAR-seropositive patients (mean score 15·8 [SD 6·4]) than for anti-NMDAR-seronegative patients (18·2 [6·8]; Cohen's d=0·36; p=0·026), as well as on the general symptoms PANSS subscale (32·9 [8·9] vs 36·1 [10·1]; d=0·33; p=0·029) and total PANSS score (65·5 [18·5] vs 72·6 [19·3]; d=0·37; p=0·013). Mean PSP score was better in anti-NMDAR-positive patients (62·0 [17·0]) than in anti-NMDAR-negative patients (53·5 [16·3]; d=0·52; p=0·014).

INTERPRETATION

Serum NMDAR antibodies are present in 3-4% of patients with schizophrenia and are associated with relatively low severity of negative symptoms and relatively good psychosocial functioning. Thus, although the findings await replication in cohorts from other geographical regions, serum anti-NMDAR antibodies might be associated with a different form of psychotic illness. These findings could inform future prognostic and interventional studies examining whether anti-NMDAR antibodies are associated with a specific course of illness or with treatment response.

FUNDING

None.

Psychiatric features in NMDAR and LGI1 antibody-associated autoimmune encephalitis

Patients with autoimmune encephalitis (AE) often developed psychiatric features during the disease course. Many studies focused on the psychiatric characteristic in anti-NMDAR encephalitis (NMDAR-E), but anti-LGI1 encephalitis (LGI1-E) had received less attention regarding the analysis of psychiatric features, and no study compared psychiatric characteristic between these two groups. The clinical data of AE patients (62 NMDAR-E and 20 LGI1-E) who developed psychiatric symptoms were analyzed in this study. In NMDAR-E, the most common higher-level feature was "behavior changes" (60/62, 96.8%) and the lower-level feature "incoherent speech" was observed in 33 patients (33/62, 53.2%), followed by "agitation" (29/62, 46.8%) and "incongruent laughter/crying" (20/62, 32.3%). Similar to NMDAR-E, "behavior changes" was most common in LGI1-E (17/20, 85.0%), but the features of suicidality, eating, and obsessive-compulsive were not reported. The top three lower-level features were visual hallucinations (9/20, 45.0%), incoherent speech (8/20, 40.0%), and mood instability (7/20, 35.0%). The comparative study found that "incongruent laughter/crying", in lower-level features, was more frequently observed in NMDAR-E (32.3% vs. 0%, p = 0.002). Moreover, the Bush Francis Catatonia Rating Scale (BFCRS) assessing the catatonic symptoms in NMDAR-E were higher than LGI1-E, but the 18 item-Brief Psychiatric Rating Scale (BPRS-18) showed no difference in the two groups. In summary, both NMDAR-E and LGI1-E often developed psychiatric symptoms. In contrast with LGI1-E, the psychiatric feature "incongruent laughter/crying" was more frequently associated with NMDAR-E, and catatonic symptoms were more severe in NMDAR-E.

B cells and the stressed brain: emerging evidence of neuroimmune interactions in the context of psychosocial stress and major depression

The immune system has emerged as a key regulator of central nervous system (CNS) function in health and in disease. Importantly, improved understanding of immune contributions to mood disorders has provided novel opportunities for the treatment of debilitating stress-related mental health conditions such as major depressive disorder (MDD). Yet, the impact to, and involvement of, B lymphocytes in the response to stress is not well-understood, leaving a fundamental gap in our knowledge underlying the immune theory of depression. Several emerging clinical and preclinical findings highlight pronounced consequences for B cells in stress and MDD and may indicate key roles for B cells in modulating mood. This review will describe the clinical and foundational observations implicating B cell-psychological stress interactions, discuss potential mechanisms by which B cells may impact brain function in the context of stress and mood disorders, describe research tools that support the investigation of their neurobiological impacts, and highlight remaining research questions. The goal here is for this discussion to illuminate both the scope and limitations of our current understanding regarding the role of B cells, stress, mood, and depression.

Biomarkers of neurodegeneration in neural autoantibody-associated psychiatric syndromes: A retrospective cohort study

Background

Autoantibody-associated psychiatric syndromes are a novel disease entity that is not fully understood. Several lines of evidence suggest that neurodegenerative processes are involved here. We are investigating whether autoantibody-positive psychiatric syndromes differ from those that are autoantibody-negative in cerebrospinal fluid (CSF) neurodegeneration markers.

Methods

We retrospectively analyzed data from 167 psychiatric patients at the University Medical Center Göttingen from 2017 to 2020. We divided this patient cohort into two, namely antibody-positive and antibody-negative. We compared various clinical features, neurodegeneration markers, and their autoantibody status in CSF and serum. We then compared both cohorts' neurodegeneration markers to a representative Alzheimer cohort. We subdivided the patients into their diverse psychiatric syndromes according to the manual to assess and document psychopathology in psychiatry (the AMDP), and compared the neurodegeneration markers.

Results

Antibody-associated psychiatric syndromes do not appear to reveal significantly greater neurodegeneration than their antibody-negative psychiatric syndromes. 71% of antibody-positive patients fulfilled the criteria for a possible and 22% for a definitive autoimmune encephalitis. Our autoantibody-positive patient cohort's relative risk to develop an possible autoimmune encephalitis was 9%. We also noted that phosphorylated tau protein 181 (ptau 181) did not significantly differ between antibody-associated psychiatric syndromes and our Alzheimer cohort. The psycho-organic syndrome usually exhibits the most prominent neurodegeneration markers, both in antibody-positive and antibody-negative psychiatric patients.

Discussion

We did not find hints for neurodegenerative processes in our antibody-positive versus AD cohort considering total tau or amyloid markers. However, our findings indicate that the neurodegeneration marker ptau181 does not differ significantly between antibody-positive and Alzheimer cohorts, further suggesting axonal neurodegeneration in antibody-positive patients as AD patients have an elevated ptau181. The evidence we uncovered thus suggests that axonal neurodegeneration might affect patients suffering from autoantibody-associated psychiatric syndromes.