Follow-up Editors' Note: Clinical, Neuroimmunologic, and CSF Investigations in First Episode Psychosis

Abstract

In “Clinical, Neuroimmunologic, and CSF Investigations in First Episode Psychosis,” Guasp et al. created an algorithm for the workup of first-episode psychosis to identify autoimmune encephalitis that includes CSF testing for (1) all patients with concomitant new-onset neurologic symptoms or (2) patients without neurologic symptoms who have abnormal serum neuronal antibodies, EEG, or brain MRI. Tebartz van Elst et al. note concerns with this algorithm because it can be challenging to determine whether cognitive deficits are neurologic or psychiatric, and it does not account for comorbidities that are associated with autoimmune encephalitis. They suggest that all patients with first-episode psychosis should have a lumbar puncture. Guasp et al. reinforce that CSF testing should be performed for all patients with first-episode psychosis of unclear etiology but emphasize that this algorithm is beneficial because it provides guidance for psychiatric facilities, where CSF testing is rarely performed. They further respond that neurologic and psychiatric cognitive deficits can be distinguished through the neurologic examination and that inclusion of comorbidities in the algorithm would be of limited value. Last, they note that the literature does not demonstrate a benefit to indiscriminate CSF testing in all patients with schizophreniform and affective disorders. In “Clinical, Neuroimmunologic, and CSF Investigations in First Episode Psychosis,” Guasp et al. created an algorithm for the workup of first-episode psychosis to identify autoimmune encephalitis that includes CSF testing for (1) all patients with concomitant new-onset neurologic symptoms or (2) patients without neurologic symptoms who have abnormal serum neuronal antibodies, EEG, or brain MRI. Tebartz van Elst et al. note concerns with this algorithm because it can be challenging to determine whether cognitive deficits are neurologic or psychiatric, and it does not account for comorbidities that are associated with autoimmune encephalitis. They suggest that all patients with first-episode psychosis should have a lumbar puncture. Guasp et al. reinforce that CSF testing should be performed for all patients with first-episode psychosis of unclear etiology but emphasize that this algorithm is beneficial because it provides guidance for psychiatric facilities, where CSF testing is rarely performed. They further respond that neurologic and psychiatric cognitive deficits can be distinguished through the neurologic examination and that inclusion of comorbidities in the algorithm would be of limited value. Last, they note that the literature does not demonstrate a benefit to indiscriminate CSF testing in all patients with schizophreniform and affective disorders.