The present disclosure relates to devices and methods for stimulating peripheral nerves in a patient via electrical, optical, mechanical, or other stimulation, in order to change the balance between parasympathetic and sympathetic activity by selectively increasing or decreasing each of parasympathetic and sympathetic activity. In a particular application, the present disclosure relates to a device for transdermal stimulation of the vagus nerve (including the auricular branch) to selectively affect the sympathetic and parasympathetic nervous system to achieve the desired therapeutic effect in a human subject.