Autoimmune Encephalitis in Postpartum Psychosis

Postpartum Psychosis: A Proposed Treatment Algorithm

Background

Postpartum psychosis (PPP) is a psychiatric emergency that generally warrants acute inpatient care. PPP is marked by the sudden onset of affective and psychotic symptoms with a rapid deterioration in mental state. Evidence suggests that PPP is a discrete disorder on the bipolar disorder spectrum with a distinct treatment profile and prognosis.

Methods

We conducted a PubMed database search for various terms involving PPP and its treatment and included peer-reviewed articles published in English.

Objective

To provide a treatment algorithm for the management of PPP based on available evidence.

Results

Pharmacological therapy is the mainstay of PPP management in the acute phase. Evidence points to a combination of antipsychotics and lithium in the acute treatment of PPP. Electroconvulsive therapy can offer a rapid treatment response where required. Lithium appears to have the best evidence for relapse prevention and prophylaxis in PPP. Psychoeducation is essential and psychosocial interventions used in bipolar disorder may be effective in PPP.

Conclusion

Early detection and prompt treatment with antipsychotics and lithium, followed by maintenance treatment with lithium, is associated with a favourable prognosis in PPP.Reprinted from J Psychopharmacol 2023; 37:960-970, with permission from Sage Journals. Copyright © 2023.

Postpartum Psychosis: A Review of Risk Factors, Clinical Picture, Management, Prevention, and Psychosocial Determinants

Postpartum psychosis is rare, but is a serious clinical and social problem. On its own, it is not included in DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) or ICD-10 (International Statistical Classification of Diseases and Related Health Problems) as a disease entity, and current diagnostic criteria equate it with other psychoses. This poses a serious legal problem and makes it difficult to classify. The disorder is caused by a complex combination of biological, environmental, and cultural factors. The exact pathophysiological mechanisms of postpartum psychosis remain very poorly understood. There is a need for further research and increased knowledge of the medical sector in the prevention and early detection of psychosis to prevent stigmatization of female patients during a psychiatric episode. It is necessary to regulate its position in the DSM5 and ICD-10. Attention should be paid to the social education of expectant mothers and their families. This article aims to review the current status of risk factors, prevention, and management of postpartum psychosis.

Postpartum psychosis: A proposed treatment algorithm

BACKGROUND

Postpartum psychosis (PPP) is a psychiatric emergency that generally warrants acute inpatient care. PPP is marked by the sudden onset of affective and psychotic symptoms with a rapid deterioration in mental state. Evidence suggests that PPP is a discrete disorder on the bipolar disorder spectrum with a distinct treatment profile and prognosis.

METHODS

We conducted a PubMed database search for various terms involving PPP and its treatment and included peer-reviewed articles published in English.

OBJECTIVE

To provide a treatment algorithm for the management of PPP based on available evidence.

RESULTS

Pharmacological therapy is the mainstay of PPP management in the acute phase. Evidence points to a combination of antipsychotics and lithium in the acute treatment of PPP. Electroconvulsive therapy can offer a rapid treatment response where required. Lithium appears to have the best evidence for relapse prevention and prophylaxis in PPP. Psychoeducation is essential and psychosocial interventions used in bipolar disorder may be effective in PPP.

CONCLUSION

Early detection and prompt treatment with antipsychotics and lithium, followed by maintenance treatment with lithium, is associated with a favourable prognosis in PPP.

Association of gestational thyroid function and thyroid peroxidase antibody positivity with postpartum depression: a prospective cohort study and systematic literature review with meta-analysis

IMPORTANCE

Postpartum depression (PPD) has a major impact on maternal and offspring well-being, with multiple possible risk factors: Studies on the association of thyroid peroxidase antibody (TPOAb) positivity and thyroid function with PPD provide heterogeneous results.

OBJECTIVE

To study the association of thyroid function and TPOAb positivity with PPD.

DESIGN

We assessed the association of TPOAb and thyroid function with PPD in a population-based prospective cohort study and performed a systematic literature review and meta-analysis.

METHODS

We measured thyroid stimulating hormone (TSH), free thyroxine (FT4), and TPOAb between 9- and 17-week gestation. Postpartum depression was assessed with Edinburgh Postpartum Depression Scale at 2-month postpartum and Brief Symptom Inventory at 2-, 6-, and 36-month postpartum. Additionally, we performed a systematic literature review and meta-analysis assessing this association.

RESULTS

In the present study, there was no association of thyroid function with PPD (TSH: odds ratio [OR] 0.83, 95% CI 0.58-1.19, P = .32; FT4: OR 0.99, 95% CI 0.95-1.05, P = .86) or TPOAb positivity with PPD (OR 0.79, 95% CI 0.47-1.33, P = .37). An impaired thyroidal response to human chorionic gonadotropin (hCG), a surrogate marker for TPOAb positivity, was associated with a lower risk of PPD (P for interaction TSH = 0.04; FT4 = 0.06). Our systematic review and meta-analysis included 3 articles that were combined with the present study. There was no statistically significant association of TPOAb positivity with PPD (OR 1.93, 95% CI 0.91-4.10, P = .08), but the results were heterogeneous (I2 = 79%).

CONCLUSIONS AND RELEVANCE

There was no significant association of TPOAb positivity, TSH, or FT4 with PPD. Our systematic review and meta-analysis revealed high heterogeneity of the current literature. Although TPOAb-positive women should be monitored for postpartum thyroiditis, our findings do not support routinely screening for PPD.

Establishment of the MGH Postpartum Psychosis Project: MGHP3

OBJECTIVE

Postpartum psychosis (PP) is a severe psychiatric disorder, with incomplete consensus on definition and diagnostic criteria. The Massachusetts General Hospital Postpartum Psychosis Project (MGHP3) was established to better ascertain the phenomenology of PP in a large cohort of diverse women spanning a wide geographical range (primarily in the US), including time of onset, symptom patterns, and associated comorbidities, psychiatric diagnoses pre- and post- the episode of PP, and also to identify genomic and clinical predictors of PP. This report describes the methods of MGHP3 and provides a status update.

METHOD

Data are collected from women who experienced PP within 6 months of childbirth and who provided this information within ten years of the study interview. Subject data are gathered during a one-time structured clinical interview conducted by phone, which includes administration of the Mini International Neuropsychiatric Interview for Psychotic Disorders Studies (Version 7.0.2), the MGHP3© Questionnaire, and other information including lifetime mental health history and use of psychiatric medications both prior to the episode of PP and during the subsequent time period prior to study interview. Subjects also provide a saliva sample to be processed for genomic analyses; a neuroimaging assessment is also conducted for a subset of participants.

RESULTS

As of July 1, 2022, 311 subjects from 44 states and 7 countries were enrolled in MGHP3. Recruitment sources include social media, online advertisements, physician referral, community outreach, and partnership with PP advocacy groups.

CONCLUSIONS

The rigorous phenotyping, genetic sampling, and neuroimaging studies in this sample of women with histories of PP will contribute to better understanding of this serious illness. Findings from MGHP3 can catalyze ongoing discussions in the field regarding proper nosologic classification of PP as well as relevant treatment implications.

Pregnancy and antibody-mediated CNS disorders: What do we know and what should we know?

Antibody-mediated central nervous system (CNS) disorders including those associated with aquaporin-4 or myelin oligodendrocyte glycoprotein IgG and autoimmune encephalitis often affect women of childbearing age. Pathogenic antibodies of these diseases can potentially alter reproductive functions and influence fetal development. Hormonal changes occurring during pregnancy may modify the course of autoimmune diseases by influencing relapse risk, attack severity, and affect the delivery and postpartum period. Moreover, balancing treatment related safety issues with the risk of potentially disabling relapses during pregnancy and breastfeeding are major challenges. Intentional prenatal, gestational, and post-partum counseling is paramount to address these issues and mitigate these risks. Fortunately, new insights on risk factors for adverse pregnancy outcomes and possible preventive strategies are emerging. This review aims to summarize the interplay between antibody-mediated CNS disorders and pregnancy during the prenatal, gestational, and postpartum periods, highlight current treatment recommendations, and discuss future areas of research.

Case Report: Possible autoimmune obsessive-compulsive disorder with postpartum onset

Autoimmune obsessive–compulsive disorder (OCD) is rare. The case presented here is that of a female patient in her mid-thirties who developed postpartum OCD. Magnetic resonance imaging showed multiple juxtacortical hyperintensities that may have been post-inflammatory in origin. In tissue-based assays using mouse brain slices, the patient’s cerebrospinal fluid (CSF) showed novel anti-nucleoli autoantibodies in cerebellar Purkinje cells and cortical neurons. The CSF dopamine and glutamate concentrations were dysregulated. The clinical course and diagnostic findings were compatible with possible autoimmune OCD with postpartum onset.

Psychiatric manifestations of autoimmune encephalitis

Autoimmune encephalitis is increasingly recognized as a cause of psychiatric symptoms. A wide spectrum of psychiatric manifestations have been described which may precede, follow or occur independently of neurologic features. Patients typically respond to immunotherapy, however diagnosis is challenging due to phenotypic heterogeneity. The aim of this review is to provide an overview of the psychiatric features associated with encephalitis mediated by autoantibodies targeting neuronal cell-surface antigens and describe indicators of potential immunopathology underlying psychiatric manifestations.

Perinatal mental illness and maternal autoimmune disease: A review of current evidence and avenues for future research

This review summarizes evidence on the association between perinatal mental illness and maternal autoimmune disease and identifies avenues for future research. Perinatal mental illness has several characteristics in common with autoimmune disease, including increased incidence in the early postpartum period, recurrence across pregnancies, evidence of elevated immune-mediated cytokines, and familial risk, as well as the general predominance of mental illness in females versus males. Several studies have demonstrated elevated risk of maternal autoimmune disease in women with perinatal mental illness, and of perinatal mental illness in those with autoimmune dysfunction, suggesting a bi-directional relationship. Further research is needed to elucidate the importance of the specific diagnosis, severity, and timing of perinatal mental illness and specific diagnosis of autoimmune disease, as well as the relative importance of perinatal versus non-perinatal mental illness. Such research could have implications for prevention, treatment, and follow-up of perinatal mental illness.

Immune System Alterations and Postpartum Mental Illness: Evidence From Basic and Clinical Research

The postpartum period is a time associated with high rates of depression and anxiety as well as greater risk for psychosis in some women. A growing number of studies point to aberrations in immune system function as contributing to postpartum mental illness. Here we review evidence from both clinical and animal models suggesting an immune component to postpartum depression, postpartum anxiety, and postpartum psychosis. Thus far, clinical data primarily highlights changes in peripheral cytokine signaling in disease etiology, while animal models have begun to provide insight into the immune environment of the maternal brain and how central inflammation may also be contributing to postpartum mental illnesses. Further research investigating peripheral and central immune function, along with neural and endocrine interactions, will be important in successfully developing novel prevention and treatment strategies for these serious disorders that impact a large portion of new mothers.

Antibodies against N-Methyl D-Aspartate Receptor in Psychotic Disorders: A Systematic Review

OBJECTIVE

The objective of this study was to provide comprehensive evidence synthesis including all available up-to-date data about the prevalence of N-methyl D-aspartate receptor (NMDAR) antibodies (ABs) in psychotic patients in order to evaluate the clinical relevance of ABs as well as to specify potential explanations of the heterogeneity of the findings and determine areas for further research.

METHODS

A literature search was conducted using the PubMed/Medline, Web of Knowledge, and Scopus databases.

RESULTS

Forty-seven studies and 4 systematic reviews (including 2 meta-analyses) were included in the present review. Studies that used cell-based assays (CBAs) provided heterogeneous results on AB prevalence, obviously depending on the type of detection assay and sample characteristics. Improvement of AB detection methods is necessary to determine the real prevalence of ABs across different groups of patients and healthy people. Live CBAs seem to have better sensitivity but probably poorer specificity than fixed CBAs. Moreover, some links between AB-positive status and acute symptoms are possible. A small amount of data on immunotherapy in AB-positive patients raises the possibility of its effectiveness but obviously require further research.

CONCLUSIONS

NMDAR ABs are definitely present in a subset of psychotic patients. NMDAR ABs might shape psychosis and underlie some symptoms, and immunotherapy might be regarded as a treatment option for patients failing to respond to other therapies.

Long-term association of pregnancy and maternal brain structure: the Rotterdam Study

The peripartum period is the highest risk interval for the onset or exacerbation of psychiatric illness in women’s lives. Notably, pregnancy and childbirth have been associated with short-term structural and functional changes in the maternal human brain. Yet the long-term effects of pregnancy on maternal brain structure remain unknown. We investigated a large population-based cohort to examine the association between parity and brain structure. In total, 2,835 women (mean age 65.2 years; all free from dementia, stroke, and cortical brain infarcts) from the Rotterdam Study underwent magnetic resonance imaging (1.5 T) between 2005 and 2015. Associations of parity with global and lobar brain tissue volumes, white matter microstructure, and markers of vascular brain disease were examined using regression models. We found that parity was associated with a larger global gray matter volume (β = 0.14, 95% CI = 0.09–0.19), a finding that persisted following adjustment for sociodemographic factors. A non-significant dose-dependent relationship was observed between a higher number of childbirths and larger gray matter volume. The gray matter volume association with parity was globally proportional across lobes. No associations were found regarding white matter volume or integrity, nor with markers of cerebral small vessel disease. The current findings suggest that pregnancy and childbirth are associated with robust long-term changes in brain structure involving a larger global gray matter volume that persists for decades. Future studies are warranted to further investigate the mechanism and physiological relevance of these differences in brain morphology.

Screening for pathogenic neuronal autoantibodies in serum and CSF of patients with first-episode psychosis

Patients with autoimmune encephalitides, especially those with antibodies to the N-methyl-D-aspartate receptor (NMDAR), often present with prominent psychosis and respond well to immunotherapies. Although most patients progress to develop various neurological symptoms, it has been hypothesised that a subgroup of patients with first-episode psychosis (FEP) suffer from a forme fruste of autoimmune encephalitis. Without accurate identification, this immunotherapy-responsive subgroup may be denied disease-modifying treatments. Thirty studies addressing aspects of this hypothesis were identified in a systematic review. Amongst other shortcomings, 15/30 reported no control group and only 6/30 determined cerebrospinal fluid (CSF) autoantibodies. To ourselves address these-and other-limitations, we investigated a prospectively ascertained clinically well-characterised cohort of 71 FEP patients without traditional neurological features, and 48 healthy controls. Serum and CSF were tested for autoantibodies against seven neuronal surface autoantigens using live cell-based assays. These identified 3/71 (4%) patient sera with weak binding to either contactin-associated protein-like 2, the NMDAR or glycine receptor versus no binding from 48 control samples (p = 0.28, Fisher's test). The three seropositive individuals showed no CSF autoantibodies and no differences from the autoantibody-negative patients in their clinical phenotypes, or across multiple parameters of peripheral and central inflammation. All individuals were negative for CSF NMDAR antibodies. In conclusion, formes frustes of autoimmune encephalitis are not prevalent among FEP patients admitted to psychiatric care. Our findings do not support screening for neuronal surface autoantibodies in unselected psychotic patients.

Postpartum psychosis: a diagnosis for the DSMV

Postpartum psychosis (PPP) is a serious disorder that is associated with maternal and infant morbidity and mortality, yet it is denied a diagnostic classification in the Diagnostic and Statistical Manual of Mental Disorders (DSM). PPP was included in the DSMI (1952) and the DSMII (1968). It was removed from DSMIII (1980). The purpose of this article is to review the history of postpartum psychosis in the DSM and provide the mechanism and research that argues for the inclusion of postpartum psychosis as a separate diagnostic entity in the DSM. This work describes a proposal to the DSMV committee in 2020 for inclusion of PPP as a unique diagnosis based on the cognitive disorganization that accompanies psychotic symptoms. The proposal for inclusion provides the required criteria such as a rationale for the proposed change and evidence that PPP is distinct from other disorders. Validators are described. Reliability studies and benefits of inclusion are provided. We were unable to gain consensus on the presence of cognitive impairment for all postpartum psychotic episodes. The committee opined that we did not demonstrate proof that PPP is a distinct diagnosis. However, the committee acknowledged that the current "specifier" may be insufficient, and thus the option favored by the committee is that it could be added to Sect. 3 of the DSM, "Conditions for Further Study." In the next proposal, we suggest that the unique temporal relationship of symptom onset to childbirth deserves consideration as unique criteria for diagnostic distinction of PPP.

Anti-NMDAR encephalitis for psychiatrists: the essentials

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis predominantly presents with psychiatric symptoms. Psychiatrists need to be alert to this diagnostic possibility, especially in female adolescents and young adults, as exemplified by the real (de-identified) case outlined below. Earlier diagnosis and immunotherapy improves long-term outcomes. Collaboration with neurology colleagues is essential for optimal care. 'Red flags' for autoimmune encephalitis and 'diagnostic clues' act as helpful aide memoires for this uncommon condition. The gold standard for testing is the detection of NMDAR antibodies in cerebrospinal fluid, but serum can be tested as a more accessible (but less reliable) preliminary step. The results of routine blood tests, magnetic resonance imaging of the head and electroencephalograms can be normal or show non-specific changes. Diagnostic criteria exist to define probable and definite cases. Immunotherapy for anti-NMDAR encephalitis is effective for many patients, but recovery is prolonged and relapses can occur.

Risk factors for postpartum relapse in women at risk of postpartum psychosis: The role of psychosocial stress and the biological stress system

BACKGROUND

Postpartum psychosis is the most severe psychiatric disorder associated with childbirth, and the risk is particularly high for women with a history of bipolar disorder, schizoaffective disorder or those who have suffered a previous episode of postpartum psychosis. Whilst there is a lot of evidence linking stress to psychosis unrelated to childbirth, the role of stress in the onset of postpartum psychosis has not been fully investigated.

METHODS

A prospective longitudinal study of 112 pregnant women, 51 at risk of postpartum psychosis because of a DSM-IV diagnosis of bipolar disorder (n = 41), schizoaffective disorder (n = 6) or a previous postpartum psychosis (n = 4) and 61 healthy women with no past or current DSM-IV diagnosis and no family history of postpartum psychosis. Women were followed up from the third trimester of pregnancy to 4 weeks' post partum. Women at risk who had a psychiatric relapse in the first 4 weeks' post partum (AR-unwell) (n = 22), were compared with those at risk who remained well (AR-well) (n = 29) on measures of psychosocial stress (severe childhood maltreatment and stressful life events) and biological stress (cortisol and inflammatory biomarkers).

RESULTS

Logistic regression analyses revealed that severe childhood maltreatment (OR = 4.9, 95% CI 0.5-49.2) and higher daily cortisol in the third trimester of pregnancy (OR=3.7, 95% CI 1.2-11.6) predicted psychiatric relapse in the first 4 weeks' post partum in women at risk of postpartum psychosis after adjusting for clinical and sociodemographic covariates.

CONCLUSION

The current study provides evidence for the role of psychosocial stress and the biological stress system in the risk of postpartum relapse in women at risk of postpartum psychosis.

The search for an autoimmune origin of psychotic disorders: Prevalence of autoantibodies against hippocampus antigens, glutamic acid decarboxylase and nuclear antigens

The etiology of psychotic disorders is still unknown, but in a subgroup of patients symptoms might be caused by an autoimmune reaction. In this study, we tested patterns of autoimmune reactivity against potentially novel hippocampal antigens. Serum of a cohort of 621 individuals with psychotic disorders and 257 controls were first tested for reactivity on neuropil of rat brain sections. Brain reactive sera (67 diseased, 27 healthy) were further tested for antibody binding to glutamic acid decarboxylase (GAD) isotype 65 and 67 by cell-based assay (CBA). A sub-cohort of 199 individuals with psychotic disorders and 152 controls was tested for the prevalence of anti-nuclear antibodies (ANA) on HEp2-substrate as well as for reactivity to double-stranded DNA, ribosomal P (RPP), and cardiolipin (CL). Incubation of rat brain with serum resulted in unidentified hippocampal binding patterns in both diseased and control groups. Upon screening with GAD CBA, one of these patterns was identified as GAD65 in one individual with schizophrenia and also in one healthy individual. Two diseased and two healthy individuals had low antibody levels targeting GAD67 by CBA. Antibody reactivity on HEp-2-substrate was increased in patients with schizoaffective disorder, but only in 3 patients did antibody testing hint at a possible diagnosis of systemic lupus erythematosus. Although reactivity of serum to intracellular antigens might be increased in patients with psychotic disorder, no specific targets could be identified. GAD antibodies are very rare and do not seem increased in serum of patients with psychotic disorders.

Influence of methodological and patient factors on serum NMDAR IgG antibody detection in psychotic disorders: a meta-analysis of cross-sectional and case-control studies

BACKGROUND

Antibodies targeting the N-methyl-D-aspartate receptor (NMDAR) have been detected in patients with psychosis. However, studies measuring the IgG subclass in serum have provided variable estimates of prevalence, and it is unclear whether these antibodies are more common in patients than controls. Because these inconsistencies could be due to methodological approaches and patient characteristics, we aimed to investigate the effect of these factors on heterogeneity.

METHODS

We searched Web of Science and Ovid (MEDLINE and PsycINFO) for cross-sectional and case-control studies published between Jan 1, 2000, and May 5, 2019, that reported NMDAR IgG antibody seropositivity in patients with psychosis. Pooled proportions and odds ratios (ORs) were derived using random-effects models. We estimated between-study variance (τ²) and the proportion of observed variance due to heterogeneity (I²). We then used univariable random-effects meta-regression analysis to investigate the effect of study factors on heterogeneity of proportions and ORs. Our protocol was registered on PROSPERO (CRD42018099874).

FINDINGS

Of 1276 articles in the initial search, 28 studies were eligible for inclusion, including 14 cross-sectional studies and 14 case-control studies. In cross-sectional studies, NMDAR IgG antibodies were detected in 0·73% (95% CI 0·09-1·38; I² 56%; p=0·026) of patients with psychosis, and in case-control studies, patients with psychosis were not significantly more likely to be seropositive than healthy individuals (OR 1·57, 95% CI 0·78-3·16; I² 15%; p=0·20). Meta-regression analyses indicated that heterogeneity was significantly associated with assay type across both study designs, illness stage in cross-sectional studies, and study quality in case-control studies. Compared with studies using a fixed cell-based assay, cross-sectional and case-control studies using the live method yielded higher pooled prevalence estimates (0·36% [95% CI -0·23 to 0·95] vs 2·97% [0·70 to 5·25]) and higher ORs (0·65 [0·33 to 1·29] vs 4·43 [1·73 to 11·36]). In cross-sectional studies, the prevalence was higher in exclusively first-episode samples than in multi-episode or mixed samples (2·18% [0·25 to 4·12] vs 0·16% [-0·31 to 0·63]), and in case-control studies, higher ORs were reported in low-quality studies than in high-quality studies (3·80 [1·47 to 9·83] vs 0·72 [0·36 to 1·42]).

INTERPRETATION

Higher estimates of NMDAR IgG antibody prevalence have been obtained with the live cell-based assay, and studies using this method find that seropositivity is more common in patients with psychosis than in controls. The effects of illness stage and study quality on heterogeneity were not consistent across study designs, and we provide clear recommendations for clinicians and researchers regarding interpreting these findings.

FUNDING

None.

Novel neuronal surface autoantibodies in plasma of patients with depression and anxiety

Neuronal surface autoantibodies (NSAbs) against various antigens cause autoimmune encephalitis. Some of these antigens are also involved in the pathology of depression and anxiety. To study whether NSAbs are more common in plasma of individuals with depression and anxiety than in controls, and to investigate if NSAbs correlate with disease status, plasma samples of 819 individuals with a current diagnosis of depression and/or anxiety, 920 in remission and 492 individuals without these disorders were included in this study. Samples were tested by a combination of immunohistochemistry (IHC), staining on live rat hippocampus neurons and cell-based assay (CBA). By IHC, 50 (2.2%) samples showed immunoreactivity to rat brain tissue, with no significant differences between the aforementioned groups (22/819 vs 18/920 vs 11/492, P > 0.99). In addition, eight IHC positive samples were positive for NSAbs on live neurons (7/819 vs 0/920 vs 1/492, P = 0.006). The IHC-staining patterns of these eight samples were atypical for autoimmune encephalitis and accordingly, they tested negative for known NSAbs by CBA. No obvious difference in the clinical characteristics between individuals with or without NSAbs was observed. In conclusion, novel NSAbs were rare but predominately found in patients with current anxiety or depression indicating they might affect mental health in a small group of patients.

Gender issues of antibody-mediated diseases in neurology: (NMOSD/autoimmune encephalitis/MG)

Neuromyelitis optica spectrum disorder (NMOSD), autoimmune encephalitis (AE), myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) are antibody-mediated neurological diseases. They have mostly female predominance, affecting many women during childbearing age. Interactions between the underlying disease (or necessary treatment) and pregnancy can occur in every of these illnesses. Herein, we present the characteristics of NMOSD, AE, MG and LEMS in general, and review published data regarding the influence of the different diseases on fertility, pregnancy, puerperium, treatment strategy during pregnancy and post-partum period, and menopause but also male factors. We summarise key elements that should be borne in mind when confronted with such cases.

Prevalence of N-Methyl-d-Aspartate Receptor antibody (NMDAR-Ab) encephalitis in patients with first episode psychosis and treatment resistant schizophrenia on clozapine, a population based study

INTRODUCTION

N-methyl-d-aspartate receptor antibody (NMDAR-Ab) encephalitis consensus criteria has recently been defined. We aimed to examine the prevalence of NMDAR-Ab encephalitis in patients with first episode psychosis (FEP) and treatment resistant schizophrenia (TRS) on clozapine, using clinical investigations, antibody testing and to retrospectively apply diagnostic consensus criteria.

METHODS

Adult (18-65 years old) cases of FEP meeting inclusion criteria were recruited over three years and assessed using the Structured Clinical Interview for DSM-IV disorders (SCID). NMDAR-Ab was identified using a live cell-based assay (L-CBA). Seropositive cases were clinically investigated for features of encephalitis including neuro-imaging, EEG and CSF where possible. Serum was retested using immunohistochemistry (IHC) as part of diagnostic criteria guidelines. A cohort of patients with TRS was also recruited.

RESULTS

112 FEP patients were recruited over 3 years. NMDAR-Ab seroprevalence was 4/112 (3.5%) cases. One case (<1%) was diagnosed with definite NMDAR-Ab encephalitis and treated with immunotherapy. One of the three other seropositive cases met criteria for probable encephalitis. However all three were ultimately diagnosed with mood disorders with psychotic features. None have developed neurological features at three year follow up. 1/100 (1%) of patients with TRS was 100 patients with TRS were recruited. One case (1%) seropositive for NMDAR-Ab but did not meet criteria for encephalitis.

CONCLUSIONS

NMDAR-Ab encephalitis as defined by consensus guidelines occured rarely in psychiatric services in this study. Further studies are needed to establish pathogenicity of serum NMDAR-Ab antibodies. Psychiatric services should be aware of the clinical features of encephalitis.

Absence of Autoantibodies Against Neuronal Surface Antigens in Sera of Patients With Psychotic Disorders

This study examines the prevalence of autoantibodies against neuronal surface antigens in the sera of individuals with psychotic disorders compared with control participants.

Testing for N-methyl-d-aspartate Receptor Autoantibodies in Clinical Practice

BACKGROUND

The diagnosis of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis relies on the detection of NMDAR IgG autoantibodies in the serum or cerebrospinal fluid (CSF) of symptomatic patients. Commercial kits are available that allow NMDAR IgG autoantibodies to be measured in local laboratories. However, the performance of these tests outside of reference laboratories is unknown.

OBJECTIVES

To report an unexpectedly low rate of NMDAR autoantibody detection in serum from patients with anti-NMDAR encephalitis tested using a commercially available diagnostic kit in an exemplar clinical laboratory.

METHODS

Paired CSF and serum samples from seven patients with definite anti-NMDAR encephalitis were tested for NMDAR IgG autoantibodies using commercially available cell-based assays run according to manufacturer's recommendations. Rates of autoantibody detection in serum tested at our center were compared with those derived from systematic review and meta-analyses incorporating studies published during or before March 2019.

RESULTS

NMDAR IgG autoantibodies were detected in the CSF of all patients tested at our clinical laboratory but not in paired serum samples. Rates of the detection were lower than those previously reported. A similar association was recognized through meta-analyses, with lower odds of NMDAR IgG autoantibody detection associated with serum testing performed in nonreference laboratories.

CONCLUSIONS

Commercial kits may yield lower-than-expected rates of NMDAR IgG autoantibody detection in serum when run in exemplar clinical (nonreference) laboratories. Additional studies are needed to decipher the factors that contribute to lower-than-expected rates of serum positivity. CSF testing is recommended in patients with suspected anti-NMDAR encephalitis.

The autoantibody-mediated encephalitides: from clinical observations to molecular pathogenesis

The autoimmune encephalitis (AE) syndromes have been characterised by the detection of autoantibodies in serum and/or cerebrospinal fluid which target the extracellular domains of specific neuroglial antigens. The clinical syndromes have phenotypes which are often highly characteristic of their associated antigen-specific autoantibody. For example, the constellation of psychiatric features and the multi-faceted movement disorder observed in patients with NMDAR antibodies are highly distinctive, as are the faciobrachial dystonic seizures observed in close association with LGI1 antibodies. These typically tight correlations may be conferred by the presence of autoantibodies which can directly access and modulate their antigens in vivo. AE remains an under-recognised clinical syndrome but one where early and accurate detection is critical as prompt initiation of immunotherapy is closely associated with improved outcomes. In this review of a rapidly emerging field, we outline molecular observations with translational value. We focus on contemporary methodologies of autoantibody detection, the evolution and distinctive nature of the clinical phenotypes, generalisable therapeutic paradigms, and finally discuss the likely mechanisms of autoimmunity in these patients which may inform future precision therapies.

Inflammatory bowel disease and new-onset psychiatric disorders in pregnancy and post partum: a population-based cohort study

OBJECTIVE

Patients with inflammatory bowel disease (IBD) have an elevated risk of mental illness. We determined the incidence and correlates of new-onset mental illness associated with IBD during pregnancy and post partum.

DESIGN

This cohort study using population-based health administrative data included all women with a singleton live birth in Ontario, Canada (2002-2014). The incidence of new-onset mental illness from conception to 1-year post partum was compared between 3721 women with and 798 908 without IBD, generating adjusted HRs (aHR). Logistic regression was used to identify correlates of new-onset mental illness in the IBD group.

RESULTS

About 22.7% of women with IBD had new-onset mental illness versus 20.4% without, corresponding to incidence rates of 150.2 and 132.8 per 1000 patient-years (aHR 1.12, 95% CI 1.05 to 1.20), or one extra case of new-onset mental illness per 43 pregnant women with IBD. The risk was elevated in the post partum (aHR 1.20, 95% CI 1.09 to 1.31), but not during pregnancy, and for Crohn's disease (aHR 1.12, 95% CI 1.02 to 1.23), but not ulcerative colitis. The risk was specifically elevated for a new-onset mood or anxiety disorder (aHR 1.14, 95% CI 1.04 to 1.26) and alcohol or substance use disorders (aHR 2.73, 95% CI 1.42 to 5.26). Predictors of a mental illness diagnosis were maternal age, delivery year, medical comorbidity, number of prenatal visits, family physician obstetrical care and infant mortality.

CONCLUSION

Women with IBD were at an increased risk of new-onset psychiatric diagnosis in the postpartum period, but not during pregnancy. Providers should look to increase opportunities for prevention, early identification and treatment accordingly.

[Recent progress in autoimmune encephalitis and its related disorders]

After the discovery of a series of autoantibodies against neuronal cell surface antigens (NSAs) of the CNS in the past 10 years, the concept of encephalitis has changed dramatically. Accordingly, a practical, syndrome-based diagnostic approach to autoimmune encephalitis was proposed in 2016. These autoantibodies have also been identified in a subset of overlapping encephalitis and demyelinating syndrome, epilepsy, first episode psychosis, movement disorders, post-herpes simplex encephalitis, progressive dementia, postpartum psychosis, stiff-person spectrum disorders, or non-REM/REM sleep behavior disorder. Although not all neuronal antibody tests are available in Japan, we have entered a new era that we have to make a correct diagnosis and start appropriate immunotherapy based on initial neurological assessment and conventional tests, without being constrained by conventional fixed ideas or normal-appearing brain MRIs while waiting for neuronal antibody test results. Although many issues need to be resolved in Japan in terms of diagnosis and treatment in autoimmune encephalitis, this review focusses on recent progress in autoimmune encephalitis and its related disorders closely related to clinical practice, including Hashimoto encephalopathy and new-onset refractory status epilepticus (NORSE).

An update on anti-NMDA receptor encephalitis for neurologists and psychiatrists: mechanisms and models

The identification of anti-NMDA receptor (NMDAR) encephalitis about 12 years ago made it possible to recognise that some patients with rapidly progressive psychiatric symptoms or cognitive impairment, seizures, abnormal movements, or coma of unknown cause, had an autoimmune disease. In this disease, autoantibodies serve as a diagnostic marker and alter NMDAR-related synaptic transmission. At symptom onset, distinguishing the disease from a primary psychiatric disorder is challenging. The severity of symptoms often requires intensive care. Other than clinical assessment, no specific prognostic biomarkers exist. The disease is more prevalent in women (with a female to male ratio of around 8:2) and about 37% of patients are younger than 18 years at presentation of the disease. Tumours, usually ovarian teratoma, and herpes simplex encephalitis are known triggers of NMDAR autoimmunity. About 80% of patients improve with immunotherapy and, if needed, tumour removal, but the recovery is slow. Animal models have started to reveal the complexity of the underlying pathogenic mechanisms and will lead to novel treatments beyond immunotherapy. Future studies should aim at identifying prognostic biomarkers and treatments that accelerate recovery.

Autoimmunity in psychotic disorders. Where we stand, challenges and opportunities

Psychotic disorders are debilitating mental illnesses associated with abnormalities in various neurotransmitter systems. The development of disease-modifing therapies has been hampered by the mostly unknown etiologies and pathophysiologies. Autoantibodies against several neuronal antigens are responsible for autoimmune encephalitis. These autoantibodies disrupt neurotransmission within the brain, resulting in a wide range of psychiatric and neurologic manifestations, including psychosis. The overlap of symptoms of autoimmune encephalitis with psychotic disorders raised the question as to whether autoantibodies against a number of receptors, ion channel and associated proteins could ultimately be responsible for some forms of psychosis. Here we review our current knowledge, on antibody mediated autoimmunity in psychotic disorders, the different diagnostic methods and their limitations, as well as on varying therapeutic approaches targeting the immune system.

The psychopathology of NMDAR-antibody encephalitis in adults: a systematic review and phenotypic analysis of individual patient data

BACKGROUND

Early immunotherapy administration improves outcomes in patients with N-methyl-D-aspartate receptor (NMDAR)-antibody encephalitis. As most patients with NMDAR-antibody encephalitis present to psychiatrists, the psychopathology of NMDAR-antibody encephalitis needs to be clearly defined to encourage accurate clinical identification and prompt treatment.

METHODS

For this systematic review, we searched PubMed for all studies published in English between Jan 1, 2005, and Oct 7, 2017, to identify individually reported adult patients (≥18 years) who satisfied consensus criteria for definite NMDAR-antibody encephalitis. After generating a list of 50 fine-grained, lower-level features, we extracted psychopathological data in addition to demographic and aetiological data. The lower-level features were later ordered within higher-level categories. As a means of quality control, we filtered the data according to proxy markers of psychiatric involvement in their description. Subsequently, we compared lower-level features from individual patient data with operationalised psychiatric syndromes using a constrained combination approach and principal component analysis, and did a network analysis to explore the inter-relationships between multiple lower-level features. The review protocol was prospectively registered with PROSPERO, number CRD42017068981.

FINDINGS

Of 1096 records identified in PubMed, 333 satisfied inclusion criteria and described 1100 patients in total with NMDAR-antibody encephalitis. The psychopathology of 505 (46%) patients with reported psychiatric symptoms was described in more detailed terms than only psychiatric or behavioural. 464 (91%) of the 505 patients were from papers in which patient data were reported individually. The remainder of the analyses focused exclusively on these 464 patients. Median age was 27 years (IQR 22-34), 368 (79%) of 464 patients were female and in 147 (32%), NMDAR-antibody encephalitis was associated with ovarian teratoma. The five higher-level categories into which the 464 patients most frequently grouped were behaviour (316 [68%]), psychosis (310 [67%]), mood (219 [47%]), catatonia (137 [30%]), and sleep disturbance (97 [21%]). The overall pattern of lower-level features was statistically stable across subgroups classified by age, sex, pregnancy association, presence of ovarian teratoma, prior herpes simplex virus encephalitis, and isolated psychiatric presentations (two-way ANOVA p=0·6-0·9). Constrained combination and principal component analyses found that mixtures of mood and psychosis syndromes fit each patient better than any single diagnosis alone, particularly for the patients in the psychiatric-described subgroup (mean ΔAkaike information criterion -0·04 in non-psychiatric-described subgroup vs 0·61 in psychiatric-described subgroup). The overlapping nature of the higher-level features was also enriched upon analysis of the psychiatric-described data (221 [67%] of 329 overlaps in non-psychiatric-described subgroup vs 96 [81%] of 118 overlaps in psychiatric-described subgroup, p=0·0052). Network analysis confirmed that the features were closely related and consistent between individual patients; the psychiatric-described subgroup had a markedly high and narrow range of closeness centralities (92% above 0·93 in psychiatric-described subgroup vs 51% above 0·93 in the non-psychiatric group).

INTERPRETATION

The distinctive aspect of NMDAR-antibody encephalitis psychopathology is complexity; core aspects of mood and psychotic disorders consistently coexist within individual patients. Alongside the predominant young female demographic, these psychopathological features could help psychiatrists identify patients who would benefit from cerebrospinal fluid testing and immunotherapies. Well-controlled prospective studies with bespoke inventories are needed to advance this clinically grounded approach.

FUNDING

Wellcome Trust, NIHR Oxford Biomedical Research Centre, NIHR Oxford Health Biomedical Research Centre, British Medical Association Foundation for Medical Research.

Autoantibodies and Psychosis

Research into antibody-mediated disease, in response to immune dysfunction or to tumour development, has rapidly expanded in recent years. Antibodies binding to neuroreceptors can cause psychiatric features, including psychosis, in a minority of patients as well as neurological features. The responsiveness of some of these cases to immunotherapy supports the hypothesis that antibody-associated mechanisms play a role in the pathogenesis of psychotic diseases. The purpose of this chapter is to review autoantibodies that are most likely to be relevant for patients with psychotic symptoms. Herein, we describe receptor structure and mechanism of action, clinical and psychiatric features for the growing number of neuronal surface antibodies, including those to the N-methyl-D-aspartate (NMDA) receptor. The identification of a subgroup of patients with psychiatric features having antibody-mediated disease highlights the importance of considering the diagnosis, particularly in those patients presenting with a first episode of psychosis.

Antibodies in the Diagnosis, Prognosis, and Prediction of Psychotic Disorders

Blood-based biomarker discovery for psychotic disorders has yet to impact upon routine clinical practice. In physical disorders antibodies have established roles as diagnostic, prognostic and predictive (theranostic) biomarkers, particularly in disorders thought to have a substantial autoimmune or infective aetiology. Two approaches to antibody biomarker identification are distinguished: a "top-down" approach, in which antibodies to specific antigens are sought based on the known function of the antigen and its putative role in the disorder, and emerging "bottom-up" or "omics" approaches that are agnostic as to the significance of any one antigen, using high-throughput arrays to identify distinctive components of the antibody repertoire. Here we review the evidence for antibodies (to self-antigens as well as infectious organism and dietary antigens) as biomarkers of diagnosis, prognosis, and treatment response in psychotic disorders. Neuronal autoantibodies have current, and increasing, clinical utility in the diagnosis of organic or atypical psychosis syndromes. Antibodies to selected infectious agents show some promise in predicting cognitive impairment and possibly other symptom domains (eg, suicidality) within psychotic disorders. Finally, infectious antibodies and neuronal and other autoantibodies have recently emerged as potential biomarkers of response to anti-infective therapies, immunotherapies, or other novel therapeutic strategies in psychotic disorders, and have a clear role in stratifying patients for future clinical trials. As in nonpsychiatric disorders, combining biomarkers and large-scale use of "bottom-up" approaches to biomarker identification are likely to maximize the eventual clinical utility of antibody biomarkers in psychotic disorders.

Glutamate-Related Antibodies and Peripheral Insulin-Like Growth Factor in Bipolar Disorder and Lithium Prophylaxis

AIMS

The aim of this study was to evaluate serum levels of the antineuronal antibodies anti-N-methyl-D-aspartate receptor (NMDAR) and anti-glutamic acid decarboxylase (GAD), and insulin-like growth factor 1 (IGF-1), in patients with bipolar disorder (BD), during manic and depressive episodes and in remission compared to euthymic patients receiving long-term lithium therapy.

METHODS

Serum levels of anti-NMDAR and anti-GAD 450/620 antibodies, as well as IGF-1, were measured using the ELISA method in 19 manic and 17 depressed patients both in an acute episode and in remission after the episode. All of the subjects were under pharmacological treatment. The control group included 18 euthymic BD patients receiving lithium for 9-44 years (mean 22 ± 11) in whom a single measurement was performed.

RESULTS

Serum levels of anti-NMDAR antibodies were higher in acute manic episodes than in lithium-treated patients. Serum levels of anti-GAD 450/620 antibodies were higher in acute manic and depressive episodes compared to remission after the respective episode. Their values in both acute manic and depressive episodes were higher than those in lithium-treated patients. Serum levels of IGF-1 were higher in acute manic episodes and in remission after mania than in lithium-treated patients.

CONCLUSION

Higher levels of anti-NMDAR and anti-GAD antibodies during episodes may point to an abnormality in the glutamatergic system in BD. Increased levels of IGF-1 during an acute manic episode and in remission after mania may constitute a compensatory mechanism against excitotoxicity. Lower levels of anti-NMDAR, anti-GAD antibodies, and IGF-1 during long-term lithium treatment may reflect normalization of this processes, contributing to mood stabilization.

Do Defective Immune System-Mediated Myelination Processes Increase Postpartum Psychosis Risk?

Postpartum (or puerperal) psychosis (PP) is a rare, severe psychiatric disorder that affects women shortly after childbirth; risk is particularly high in individuals with a history of bipolar disorder or PP, but the underlying pathophysiology remains poorly understood. Emerging evidence suggests that immune system (dys)function plays an important role in disorder onset. On the basis of new findings from clinical and animal model studies, we hypothesise that the abundance and/or activity of regulatory T cells, and the efficacy of consequent (re)myelination processes in the brain mediated by CCN proteins, is perturbed in PP; this pathway may be modulated by risk and protective/treatment factors for the disorder, and identifying abnormalities within it could signpost novel predictive biomarkers and therapeutic targets.

Anti-NMDA receptor encephalitis presenting as postpartum psychosis-a clinical description and review

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is increasingly being recognised to be associated with protean neuropsychiatric manifestations. Anti-NMDAR encephalitis is considered to be the most common amongst the autoimmune-mediated encephalitic disorders. It is caused by the autoantibodies against GluN1 subunits of N-methyl-D-aspartate (NMDA) receptor and manifests with prominent psychiatric symptoms, especially during the initial phase of illness. Literature anti-NMDAR encephalitis presenting with postpartum psychosis is scant. In this report, we present a 28-year-old lady with postpartum psychosis as presenting manifestation of anti-NMDAR encephalitis and discuss the neuropsychiatric manifestations of this emerging entity.

SULFATION PATHWAYS: The steroid sulfate axis and its relationship to maternal behaviour and mental health

Steroid hormones can exist in functionally dissociable sulfated and non-sulfated (free) forms and can exert profound effects on numerous aspects of mammalian physiology; the ratio of free-to-sulfated steroids is governed by the antagonistic actions of steroid sulfatase (STS) and sulfotransferase (SULT) enzymes. Here, I examine evidence from human and animal model studies, which suggests that STS and its major substrate (dehydroepiandrosterone sulfate, DHEAS) and product (DHEA) can influence brain function, behaviour and mental health, before summarising how the activity of this axis varies throughout mammalian pregnancy and the postpartum period. I then consider how the steroid sulfate axis might impact upon normal maternal behaviour and how its dysfunction might contribute towards risk of postpartum psychiatric illness. Understanding the biological substrates underlying normal and abnormal maternal behaviour will be important for maximising the wellbeing of new mothers and their offspring.

Postpartum psychiatric disorders

Pregnancy is a complex and vulnerable period that presents a number of challenges to women, including the development of postpartum psychiatric disorders (PPDs). These disorders can include postpartum depression and anxiety, which are relatively common, and the rare but more severe postpartum psychosis. In addition, other PPDs can include obsessive-compulsive disorder, post-traumatic stress disorder and eating disorders. The aetiology of PPDs is a complex interaction of psychological, social and biological factors, in addition to genetic and environmental factors. The goals of treating postpartum mental illness are reducing maternal symptoms and supporting maternal-child and family functioning. Women and their families should receive psychoeducation about the illness, including evidence-based discussions about the risks and benefits of each treatment option. Developing effective strategies in global settings that allow the delivery of targeted therapies to women with different clinical phenotypes and severities of PPDs is essential.

Are infectious agents involved in the pathogenesis of postpartum psychosis?

BACKGROUND

Since postpartum psychosis has been linked to activation of the immune system, it has been hypothesized that infectious agents may be involved in the pathogenesis of this disorder. We therefore investigated whether exposure to pathogens that can infect the central nervous system is increased in patients with postpartum psychosis.

METHODS

We measured the prevalence and titers of immunoglobulin G (IgG) and M (IgM) to herpes simplex virus type 1 (HSV-1) and 2 (HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV) and Toxoplasma Gondii (TG) in a cohort of patients with postpartum psychosis (n = 81) and compared these to matched postpartum controls.

RESULTS

We did not find significant differences in seroprevalence or antibody titers for any of these pathogens.

LIMITATIONS

Limitations of this study include the indirect measurement of infectious disease and the cross-sectional design.

CONCLUSION

Our results do not support the hypothesis that exposure to these neurotropic pathogens is involved in postpartum psychosis.

The prevalence and treatment outcomes of antineuronal antibody-positive patients admitted with first episode of psychosis

BACKGROUND

Antineuronal antibodies are associated with psychosis, although their clinical significance in first episode of psychosis (FEP) is undetermined.

AIMS

To examine all patients admitted for treatment of FEP for antineuronal antibodies and describe clinical presentations and treatment outcomes in those who were antibody positive.

METHOD

Individuals admitted for FEP to six mental health units in Queensland, Australia, were prospectively tested for serum antineuronal antibodies. Antibody-positive patients were referred for neurological and immunological assessment and therapy.

RESULTS

Of 113 consenting participants, six had antineuronal antibodies (anti-N-methyl-D-aspartate receptor antibodies [n = 4], voltage-gated potassium channel antibodies [n = 1] and antibodies against uncharacterised antigen [n = 1]). Five received immunotherapy, which prompted resolution of psychosis in four.

CONCLUSIONS

A small subgroup of patients admitted to hospital with FEP have antineuronal antibodies detectable in serum and are responsive to immunotherapy. Early diagnosis and treatment is critical to optimise recovery.

DECLARATION OF INTEREST

None.

No neuronal autoantibodies detected in plasma of patients with a bipolar I disorder

A subpopulation of patients with bipolar disorder type I (BD-I) might suffer from undiagnosed autoimmune encephalitis. We tested plasma of 104 BD-I patients with a current or recent manic episode in the past 2 years for the presence of neuronal autoantibodies using immunohistochemistry, immunocytochemistry and cell-based assay (CBA). Neuronal antibodies were not detected in any of the BD type I. This finding suggests that the frequency of an undiagnosed autoimmune encephalitis in patients with BD I is less than 1%. However, these findings need to be confirmed in cerebrospinal fluid and/or blood of acutely ill manic patients.

Psychosis: an autoimmune disease?

Psychotic disorders are common and disabling. Overlaps in clinical course in addition to epidemiological and genetic associations raise the possibility that autoimmune mechanisms may underlie some psychoses, potentially offering novel therapeutic approaches. Several immune loci including the major histocompatibility complex and B-cell markers CD19 and CD20 achieve genome-wide significance in schizophrenia. Emerging evidence suggests a potential role via neurodevelopment in addition to classical immune pathways. Additionally, lymphocyte biology is increasingly investigated. Some reports note raised peripheral CD19+ and reduced CD3+ lymphocyte counts, with altered CD4 : CD8 ratios in acute psychosis. Also, post-mortem studies have found CD3+ and CD20+ lymphocyte infiltration in brain regions that are of functional relevance to psychosis. More specifically, the recent paradigm of neuronal surface antibody-mediated (NSAb) central nervous system disease provides an antigen-specific model linking adaptive autoimmunity to psychopathology. NSAbs bind extracellular epitopes of signalling molecules that are classically implicated in psychosis such as NMDA and GABA receptors. This interaction may cause circuit dysfunction leading to psychosis among other neurological features in patients with autoimmune encephalitis. The detection of these cases is crucial as autoimmune encephalitis is ameliorated by commonly available immunotherapies. Meanwhile, the prevalence and relevance of these antibodies in people with isolated psychotic disorders is an area of emerging scientific and clinical interest. Collaborative efforts to achieve larger sample sizes, comparison of assay platforms, and placebo-controlled randomized clinical trials are now needed to establish an autoimmune contribution to psychosis.

Phenotypical characteristics of postpartum psychosis: A clinical cohort study

OBJECTIVES

Postpartum psychosis (PP) is known for its clear onset but its phenotype has never been clearly described in a cohort. The aim of this study was to describe PP symptomatology, and to identify subgroups of patients based on symptom profiles.

METHODS

We prospectively assessed a wide range of symptoms in cases of PP in a cohort of women (N=130) admitted to the Mother-Baby inpatient unit. Using a person-centered analytic approach, we distinguished mutually exclusive subgroups of women. Subgroups were related to demographic and clinical characteristics.

RESULTS

The most prevalent symptoms of PP were irritability (73%), abnormal thought content (72%), and anxiety (71%). Suicidal and infanticidal ideation was present in 19% and 8% of patients, respectively. Delusions and hallucinations often had a negative content. Latent class analysis revealed three symptom profiles, a manic (34%), depressive (41%) and atypical (25%) profile, respectively. The manic profile is characterized by manic symptoms and agitation, the depressive profile by depressive and anxiety symptoms, and the atypical profile by disturbance of consciousness and disorientation. In women with a depressive profile, treatment was started 2 weeks later (P=.049), and more often voluntarily, than in manic and atypical women (P=.037).

CONCLUSIONS

We distinguished subgroups of PP patients with a manic, depressive, and atypical profile. Disturbance of consciousness, disorientation, and depersonalization/derealization were less prevalent than previously suggested in the literature. Instead, the depressive profile was the most prevalent, but the depressive profile can easily remain undetected, which could lead to treatment delay and risk of suicide/infanticide. Within the manic profile, irritability was highly prevalent and occurred more often than elevated mood.

CASPR2 autoantibodies are raised during pregnancy in mothers of children with mental retardation and disorders of psychological development but not autism

BACKGROUND, METHODS AND OBJECTIVES

Maternal autoantibodies to neuronal proteins may be one cause of neurodevelopmental disorders. This exploratory study used the Danish archived midgestational sera and their nationwide registers to search for antibodies to the N-methyl-D-aspartate receptor (NMDAR) and contactin-associated protein-like 2 (CASPR2) in maternal sera, and to relate them to subsequent psychiatric diagnoses in the woman or her child.

RESULTS

In a sample of 192 women, there was no association between antibody status and subsequent psychosis in the mothers. However, NMDAR antibodies (n=4) or CASPR2 antibodies (n=1) were identified in 5/11 (45.5%) women whose children were given a diagnosis of mild or unspecified mental retardation or disorders of psychological and motor development (collectively abbreviated as mental retardation and/or disorders of psychological development (MR/DPD)) compared with 9/176 (5.1%) of the remaining mother (p<0.001). These findings were followed up in a specifically selected cohort, in which CASPR2 antibodies were detected in 7/171 (4.1%) mothers of MR/DPD progeny, compared with only 1/171 (0.6%) control mother (p=0.067). The combined sample showed a significantly higher frequency of CASPR2 antibodies in mothers of MD/DPD children (p=0.01). These autoantibodies were not increased in mothers of children with autistic spectrum disorder.

CONCLUSIONS

These findings complement the known roles of CASPR2 in brain development, and warrant further epidemiological and experimental studies to clarify the role of CASPR2 and possibly other antibodies in neurodevelopmental disorders.

Understanding the pathophysiology of postpartum psychosis: Challenges and new approaches

Postpartum psychosis is a severe psychiatric condition which affects 1-2 of every 1000 mothers shortly after childbirth. Whilst there is convincing evidence that the condition is precipitated by a complex combination of biological and environmental factors, as yet the pathophysiological mechanisms remain extremely poorly defined. Here, I critically review approaches that have been, or are being, employed to identify and characterise such mechanisms; I also review a recent animal model approach, and describe a novel biological risk model that it suggests. Clarification of biological risk mechanisms underlying disorder risk should permit the identification of relevant predictive biomarkers which will ensure that “at risk” subjects receive prompt clinical intervention if required.

Immune system aberrations in postpartum psychosis: An immunophenotyping study from a tertiary care neuropsychiatric hospital in India

Postpartum psychosis (PP) is associated with significant morbidity to both mother and infant. Immune system dysregulation during PP is reported in recent studies. This study attempted to determine immune signatures associated with first-onset PP by flow cytometry. Peripheral blood showed decreased naive CD4 and CD8 T cells, while activated CD8 and memory regulatory T cells (Tregs) were increased in women with PP as against healthy controls. The CD14^-CD16⁺non-classical monocytes, CD11c+myeloid DCs and cytotoxic CD56^dimCD16⁺ were reduced, while CD56^brtCD16^+/-regulatory NK cells were elevated in women with PP. The variations in immune cell subsets highlight the generalized immune dysregulation in PP.

Autoantibodies to Synaptic Receptors and Neuronal Cell Surface Proteins in Autoimmune Diseases of the Central Nervous System

Investigations in the last 10 years have revealed a new category of neurological diseases mediated by antibodies against cell surface and synaptic proteins. There are currently 16 such diseases all characterized by autoantibodies against neuronal proteins involved in synaptic signaling and plasticity. In clinical practice these findings have changed the diagnostic and treatment approach to potentially lethal, but now treatable, neurological and psychiatric syndromes previously considered idiopathic or not even suspected to be immune-mediated. Studies show that patients' antibodies can impair the surface dynamics of the target receptors eliminating them from synapses (e.g., NMDA receptor), block the function of the antigens without changing their synaptic density (e.g., GABAb receptor), interfere with synaptic protein-protein interactions (LGI1, Caspr2), alter synapse formation (e.g., neurexin-3α), or by unclear mechanisms associate to a new form of tauopathy (IgLON5). Here we first trace the process of discovery of these diseases, describing the triggers and symptoms related to each autoantigen, and then review in detail the structural and functional alterations caused by the autoantibodies with special emphasis in those (NMDA receptor, amphiphysin) that have been modeled in animals.

Synaptic and Neuronal Autoantibody-Associated Psychiatric Syndromes: Controversies and Hypotheses

Autoimmune encephalitis (AE) mediated by antibodies against synaptic and neuronal surface targets frequently presents with a psychiatric syndrome. In these patients, removal of autoantibodies treats the disease and outcomes are closely linked to early intervention. The discovery of these autoantibodies in isolated psychiatric syndromes has raised the possibility that these patients may derive similar benefits from immunotherapy, a potentially transformational approach to the treatment of mental illness. Although open-label case series suggest impressive therapeutic outcomes, the pathological relevance of these autoantibodies outside of canonical presentations is debated. The advent of diagnostic criteria for AE attempts to facilitate its prompt identification but risks prematurely neglecting the potential scientific and clinical significance of isolated syndromes that do not satisfy these criteria. Here, we propose using a syndrome-level taxonomy that has occasional, but not necessary, overlap with AE: synaptic and neuronal autoantibody-associated psychiatric syndromes or "SNAps". This will prevent confusion with AE and act heuristically to promote active investigation into this rare example of psychopathology defined on a molecular level. We suggest that this concept would have application in other autoantibody-associated syndromes including seizure, cognitive, and movement disorders, in which similar issues arise. We review putative direct and indirect mechanisms and outline experimentally testable hypotheses that would help to determine prospectively in whom autoantibody detection is relevant, and as important, in whom it is not. We summarize a pragmatic approach to autoantibody testing and management in severe mental illness in order to promptly diagnose AE and advocate a research-orientated experimental medicine paradigm for SNAps, where there is greater equipoise. We conclude that SNAps remains a nascent area of clinical neuroscience with great potential and in ongoing need of psychiatry-led basic and clinical research.

Postpartum Anti-N-methyl-D-aspartate Receptor Encephalitis: A Case Report and Literature Review

We describe a 24-year-old woman with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis that developed 3 weeks after normal delivery. She was treated with methylprednisolone, intravenous immunoglobulin, and plasmapheresis, in addition to teratoma excision. However, her recovery was slow, and dysmnesia and mental juvenility persisted even two years after onset. To date, five patients with postpartum anti-NMDAR encephalitis have been reported. All of those patients showed psychotic symptoms and were suspected of having postpartum psychosis in the early period of the encephalitis. Changes in hormonal factors, modification of immune tolerance, or retrograde infection of the ovary may be contributing factors for postpartum anti-NMDAR encephalitis.

Prevalence of serum anti-neuronal autoantibodies in patients admitted to acute psychiatric care

BACKGROUND

Autoimmune encephalitis associated with anti-neuronal antibodies may be challenging to distinguish from primary psychiatric disorders. The significance of anti-neuronal antibodies in psychiatric patients without clear evidence of autoimmune encephalitis is unknown. We investigated the serum prevalence of six anti-neuronal autoantibodies in a cohort of unselected patients admitted to acute psychiatric care.

METHOD

Serum was drawn from 925 patients admitted to acute psychiatric in-patient care. Psychiatric diagnoses were set according to International Classification of Diseases (ICD)-10 criteria. Antibody analysis was performed with an indirect immunofluorescence test for N-methyl d-aspartate receptor (NMDAR) antibodies and five other anti-neuronal autoantibodies of the immunoglobulin (Ig) classes IgA, IgG and IgM isotype.

RESULTS

Anti-neuronal autoantibodies were found in 11.6% of patients: NMDAR antibodies in 7.6%, contactin-associated protein-like 2 (CASPR2) antibodies in 2.5%, glutamic acid decarboxylase-65 (GAD65) antibodies in 1.9%, and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antibodies in 0.1%. Leucine-rich glioma-inactivated protein-1 (LGI1) and γ-aminobutyric acid B (GABAB) receptor antibodies were not detected. NMDAR antibodies of class IgG were present in five patients only (0.5%). NMDAR antibodies of all Ig classes were equally prevalent in patients with and without psychosis. There were no significant differences in antibody prevalence in the different diagnostic categories, except for a higher odds ratio of being NMDAR antibody positive for patients without a specific psychiatric diagnosis.

CONCLUSIONS

NMDAR IgG autoantibodies, which are known to be strongly associated with anti-NMDAR encephalitis, were rarely found. CASPR2 and GAD65 antibodies were more frequently encountered in the present study than previously reported. Further research on the clinical significance of anti-neuronal autoantibodies in patients with acute psychiatric symptoms is needed.