Most patients with anti‐NMDA receptor (NMDAR) encephalitis present with acute psychosis which is difficult to differentiate from psychotic episodes related to a primarily psychiatric disease. A precise description of the psychiatric phenotype of this disease would greatly facilitate the early diagnosis of these patients. We provide here a detailed description of three of these patients and the similarity of the clinical features with cycloid psychosis. All three patients met Perris and Brockington's criteria for cycloid psychosis in the initial phase of the autoimmune process, including among other an acute and polysymptomatic onset, polymorphous psychotic symptomatology, mood swings, and changes in psychomotricity. In addition, none of the patients had experienced an extended psychiatric prodromal phase. External stress factors preceded symptom onset in the three patients, who also showed common base personality traits and intolerance to a range of antipsychotic treatments. Complementary studies disclosed that the three patients had ovarian teratoma as well as abnormal EEG, and CSF antibodies against NMDAR. Patients with anti‐NMDAR encephalitis may present with clinical features that resemble cycloid psychosis. In addition, our patients did not have prodromal history of psychiatric symptoms and showed intolerance to antipsychotic medication, which all should raise concern for anti‐NMDAR encephalitis, prompting CSF antibody testing.

Objective We reviewed the psychotic symptoms of anti‐NMDA receptor encephalitis (NMDARE) to differentiate its presentation from those found in a primary psychiatric disorder. We hypothesized that the cycloid psychosis (CP) phenotype would be a frequent clinical presentation in the psychiatric phase of NMDARE. Method A systematic literature review in PubMed of all case reports published on NMDARE was performed from database inception to March 2020. We included all cases where psychotic symptoms were reported and whose diagnoses were confirmed by the presence of anti‐NMDAR antibodies in the cerebrospinal fluid (CSF). An email including a short test (CP phenotype, Perris and Brockington's criteria) was sent to all case report authors asking them to describe the psychotic symptoms. Results We identified 335 case reports fulfilling our criteria, and the authors of 200 replied. Our analyses were based exclusively on those answers and data extracted from the articles. Median patient age was 25 years (+‐11.4), 81% were female, and 39% had an ovarian teratoma. A complete CP phenotype was identified in 175 patients (87%). These were acute psychotic episodes with a sudden onset and a fluctuating clinical pattern mostly characterized by confusion (97%), delusions (75%), hallucinations (69%), motility disturbances (87%), and mood oscillations (80%). Conclusion The complete CP phenotype was frequently the expression of psychotic symptoms in NMDARE. We suggest that patients with a first psychotic episode who initially exhibit the CP phenotype should undergo CSF analysis to determine whether antibodies against neuronal cell surface or synaptic receptors are present to rule out a possible diagnosis of autoimmune encephalitis.

Aims: Cycloid psychosis (CP) is a clinical entity characterized by sudden onset of psychotic polymorphic symptomatology and fluctuant course. It has a reported rate of psychosocial precipitating factors ranging 30-65%. The aim of the study was to describe all cases of CP, admitted in our Psychiatry ward, during the first two months of the COVID-19 pandemic. Method: In this retrospective and observational study, we reported a sample of eight patients who were treated as inpatients in the psychiatric ward of our hospital during the first two months of COVID-19 pandemic (mid-March to mid-May 2020) and compared it with previous years. All our patients fulfilled all four Perris & Brockington criteria for CP. We reported the sociodemographic, clinical and biological parameters. Results: In our sample, all of the patients had maladaptive personality traits; the major external stressing factor was COVID-19; all our patients had short prodromal symptomatology, short Duration of Untreated Psychosis (DUP) and high score at the Positive Scale at Positive and Negative Syndrome Scale (PANSS-P) at hospital admission with the majority showing psychotic symptoms related to the actual COVID-19 pandemic. The predominant treatment during admission was olanzapine and a short time to full remission of psychotic symptoms was observed in all patients. Conclusion: We found an increase in the admission of patients with CP during the first two months of the actual pandemic. Stress caused by the COVID-19 situation has possibly incremented the frequency of stress-related disorders and it has also influenced its clinical presentation.