Ethics of mood modulation

Directly altering affect with an implanted device raises questions distinct from those of motor neuroprosthetics. Concerns include agency and authenticity (are the resulting feelings genuinely the patient's own?), personality or identity change reported by some DBS recipients, the quality of informed consent in desperately ill and hopeful populations, and the risk of stimulation-induced hypomania, impulsivity or blunting.

Because an affective biomarker also constitutes a continuous readout of a person's inner emotional state, mental-privacy concerns are acute here in a way they are not for a limb prosthesis. These issues intensify with closed-loop systems that adjust a person's affect automatically and continuously, sharpening the question of who — patient, clinician, or algorithm — is ultimately in control of a mood, and where the line falls between restoring health and enhancing normal emotion.