Unraveling the significant complexity of brain-immune interactions could provide essential new insights and potential treatment considerations for the clinical neurosciences. Despite considerable research relating immunological changes to major neuropsychiatric disorders, it has been difficult to establish that immunological processes are involved in the development of central nervous system pathology associated with these disorders. This brief article highlights some of the landmark basic studies and seeks to convey essential principles guiding research in brain-immune interactions. Research in this area often incorporates several disciplines, ranging from psychology and neuroscience to immunology and molecular genetics. The clinical implications of this area of research are discussed, with emphasis on the challenge of disentangling pathogenic factors and valid markers of disease from epiphenomena.

Initial investigations of the possible interaction between schizophrenia and the immune system began in the early 1900s and have proceeded in a rather halting fashion because of the methodological challenges faced by investigators. However, a confluence of recent data suggests that activation of the inflammatory response system, the cellular immune system, and the humoral immune system may be present in some patients with schizophrenia. Some of the most compelling data support the hypothesis that minor levels of immune activation may be associated with acute psychotic exacerbations. However, a second body of evidence suggests that some individuals with schizophrenia may have chronic, evolving autoimmune processes. This article is an overview of the history, rationale, and some of the recent findings on the interaction between schizophrenia and the immune system.

How can clinicians diagnosis generalized anxiety disorder (GAD) earlier and treat it more effectively? The most successful treatment is often determined through the remission of psychic and somatic symptoms, an increase in functional capacity at work and in relationships, and how the patient handles their daily responsibilities. This monograph attempts to:

—Define GAD

—Explore psychotherapeutic and pharmacologic treatment modalities

—Identify comorbidities associated with GAD

—Understand the importance of dual uptake mechanisms in gaining remission

A subgroup of patients with childhood-onset obsessive-compulsive disorder (OCD) has been identified who share a common clinical course characterized by dramatic symptom exacerbations following Group A beta-hemolytic streptococcal (GABHS) infections. The term PANDAS has been applied to the subgroup, to indicate the postulated etiology of their symptoms: Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections. Five clinical characteristics define the PANDAS subgroup: presence of OCD and/or tic disorder, prepubertal symptom onset, sudden onset or abrupt exacerbations (sawtooth course), association with neurological abnormalities (presence of adventitious movements or motoric hyperactivity during exacerbations), and temporal association between symptom exacerbations and GABHS infections. Post-streptococcal symptom exacerbations are typically quite dramatic, with patients reporting that their symptoms “…came on overnight” or “…appeared all of a sudden a few days after I had a sore throat.” The post-streptococcal inflammatory nature of the neuropsychiatric symptoms provides novel opportunities for treatment and prevention, including immunomodulatory therapies such as therapeutic plasma exchange (TPE) and intravenous immunoglobulin (IVIG). A recently completed placebo-controlled trial revealed that both IVIG and TPE were effective in reducing neuropsychiatric symptom severity (40% to 55% reductions, respectively) for a group of severely ill children with OCD and/or tic disorders. Further research is required to determine why the treatments are helpful, as well as to ascertain whether or not antibiotic prophylaxis can help prevent post-streptococcal symptom exacerbations.

Stiff-person syndrome (SPS) is a rare disease of severe progressive muscle stiffness in the spine and lower extremities with superimposed muscle spasms triggered by external stimuli. Patients with SPS are often referred for psychiatric evaluation and the psychiatrist may be the first to diagnosis SPS. Psychosocial stressors often precede the first manifestations of the disease; depression, anxiety, and alcohol abuse are comorbid illnesses. The identification of an association with antibodies to glutamic acid decarboxylase (GAD) was invaluable for definitively establishing a pathological basis for the disease; antibodies to amphiphysin and gephyrin are also found in cases of SPS but at much lower frequencies. Whether the antibodies inhibit GAD activity in vivo, target GAD-expressing neurons for immune-mediated destruction, are part of a wider immune process, or are merely a marker for destruction of GAD-expressing neurons by an independent neurodegenerative process is not yet clear. Both electromyography and the detection of GAD antibodies are useful in establishing a diagnosis of SPS. Treatment of SPS includes the use of immunomodulating therapies (plasmapheresis and intravenous immunoglobulins) and symptomatic treatment with benzodiazepines and baclofen. The use of tricyclic antidepressants and rapid withdrawal from therapy should be avoided.

Rasmussen's syndrome (chronic encephalitis with epilepsy) is a rare neurological disorder of unknown cause characterized by severe epilepsy, hemiplegia, dementia, and inflammation of the brain, and progressive functional and structural destruction of a single cerebral hemisphere. While one mechanism underlying the pathogenesis of Rasmussens encephalitis has been hypothesized to be mediated by production of excitotoxic GluR3 autoantibodies to the a-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor, other neuropathological etiologies have also been indicated. Proposed therapies have included antiepileptics, steroids, antiviral agents, alpha-interferon, and immunoglobulin. The mainstay of therapy is surgical hemispherectomy. To date, no medical therapies have permanently halted neurologic deterioration.