A 62-year-old female with chronic sleep-onset insomnia and a history of benzodiazepine use disorder in sustained remission seeks treatment for her sleep difficulties. She firmly refuses benzodiazepines and Z-drugs due to prior addiction. The PMHNP recommends ramelteon 8 mg at bedtime. The patient asks why this medication would not lead to dependence. Which of the following best explains ramelteon's unique pharmacological profile?