A referred case of a 34-year-old woman was brought to the emergency room with features of mutism and whole-body rigidity following rapid correction of hyponatremia. On presentation, she was ill looking with tremors on her both hands and legs. She was unresponsive to command and developed involuntary outbursts of laughter and crying. Based on clinical features and neuroimaging, diagnosis of isolated extrapontine myelinolysis was made. She was treated with quetiapine, vitamin B1 and B12 supplements, trihexyphenidyl, levodopa-carbidopa and physiotherapy of limbs. Due to lack of clinical trials for adequate diagnosis and management of extrapontine myelinolysis, this case report highlights the importance of extrapontine myelinolysis with neuropsychiatric manifestation in research world.