Unmasking bipolarity in recurrent depressive disorder following herpes simplex virus triggered n-methyl-D-aspartate encephalitis.

Objective: Herpes simplex virus (HSV) infection triggered n-methyl-D-aspartate (NMDA) encephalitis can lead to varied neuropsychiatric manifestations, including movement disorders and manic symptoms. HSV is known to affect the same brain regions as in secondary mania.

Method: We present a 35-year-old female diagnosed with recurrent depressive disorder (RDD) who developed NMDA encephalitis triggered by HSV infection.

Result: HSV-triggered NMDA encephalitis led to a manic switch in a woman with RDD on antidepressants, along with the new onset of dyskinetic movements.

Conclusion: A neurological insult predisposed our patient to the variable effects of antidepressant drugs.