Autoimmune mediated suicidal behavior

There is a known autoimmune disease, which is called ‘anti-NMDA receptor encephalitis’, or ‘Dalmau encephalitis’ (named after its discoverer). It is associated with the presence of high titers of antibodies to a certain epitope of the NR1 subunit of NMDA receptors in the blood and/or in the cerebrospinal fluid. This disease in its classic form is accompanied by severe mental (depression, delusions, hallucinations, anxiety, sleep disorders, cognitive impairment, catatonia, etc.) and neurological (convulsions, dyskinesias) symptoms, disturbances of consciousness and autonomic regulation (regulation of respiration, temperature, blood pressure, heart rhythm), as well as with suicidality, which seems to be disproportionate to the severity of mental disturbances. However, there are also ‘non-classical’ forms of anti-NMDA receptor encephalitis. These can manifest with exclusively psychiatric symptoms (for example, depression, psychosis, suicidal behavior), without characteristic neurological symptoms and/or disorders of autonomic regulation. In some of these cases, the correct diagnosis of anti-NMDA receptor encephalitis was delayed by months, years or even decades. In addition, in recent decades, increasing evidence had accumulated that in some patients with so-called ‘classical’ mental disorders, such as schizophrenia, bipolar affective disorder, depressive disorders – and especially in those who show resistance to traditional psychopharmacotherapy – elevated titers of anti-NMDA receptor antibodies can be detected in their blood and/or in their cerebrospinal fluid. It has also been shown that elevated blood titers of anti-NMDA receptor antibodies are often detected in post-mortem examinations of suicide victims. Anti-NMDA receptor antibody titers in psychiatric patients correlate well with a recent history of suicide attempts and/or with current active suicidal ideation. Some of these patients may benefit from aggressive immunosuppressive therapy that is similar to the regimens normally used to treat ‘classical’ anti-NMDA receptor encephalitis with neurological and autonomic manifestations. This might stop their suicidal ideation and/or help in overcoming their resistance to psychopharmacotherapy. This article presents a description and analysis of three clinical cases of patients with various mental disorders, acute suicidality and elevated titers of anti-NMDA receptor antibodies, in whom such therapy has been effective.