The differential diagnosis of non-convulsive status epilepticus (NCSE) is often complex due to a wide clinical variability of its presentation, including psychiatric manifestations. We report a 68 years old male with a history of depression treated with venlafaxine, mirtazapine, quetiapine and risperidone, presenting in the emergency room with confusion and generalized rigidity. A brain CT scan did not show lesions. A neuroleptic syndrome was initially suspected. At the third day the obtundation worsened and an electroencephalogram (EEG) was performed, which showed epileptiform abnormalities. Treatment with valproic acid resulted in disappearance of such abnormalities. After three weeks of mechanical ventilation, the patient was extubated and remained lucid and partially orientated in time and space.The differential diagnosis of non-convulsive status epilepticus (NCSE) is often complex due to a wide clinical variability of its presentation, including psychiatric manifestations. We report a 68 years old male with a history of depression treated with venlafaxine, mirtazapine, quetiapine and risperidone, presenting in the emergency room with confusion and generalized rigidity. A brain CT scan did not show lesions. A neuroleptic syndrome was initially suspected. At the third day the obtundation worsened and an electroencephalogram (EEG) was performed, which showed epileptiform abnormalities. Treatment with valproic acid resulted in disappearance of such abnormalities. After three weeks of mechanical ventilation, the patient was extubated and remained lucid and partially orientated in time and space.