Reduced reward responsiveness in treatment resistant depression of middle-aged adults: Association with carotid artery stiffness and tetrahydrobiopterin oleh Kalpana K. Barhwal, Barsha Parida, Jigyansa Pattnaik, Praveen Rowlo, Sudipta Mahakud, Suravi Patra, Bodepudi N. Rao, Bidhubhusan Mahapatra