Review Question - QID 216766

A 23-year-old woman presents to the emergency department for a tremor in her hand. She has presented several times in the past for this diagnosis with no clear etiology for her symptoms. She states the symptoms are associated with stress and sleep deprivation. She is generally healthy and does not use any drugs or take any medications. Her temperature is 98°F (36.7°C), blood pressure is 127/68 mmHg, pulse is 73/min, and respirations are 16/min. Physical exam reveals a tremor in the patient's left hand. The tremor goes away while the patient uses her phone and while she is speaking. The patient is able to write her name without difficulty and her neurologic exam, including strength, sensation, and cerebellar tests, are all within normal limits. Which of the following is the most likely diagnosis?