Since the Nuremberg trials (1947–1949), informed consent has become central for ethical practice in patient care and biomedical research. Codes of ethics emanating from the Nuremberg Code (1947) recognize the importance of protecting patients and research subjects from abuses, manipulation and deception. Informed consent empowers individuals to autonomously and voluntarily accept or reject participation in either clinical treatment or research. In some cases, however, the underlying mental or physical condition of the individual may alter his or her cognitive abilities and (...) compromise the informed consent process. This is particularly true in chronic psychiatric conditions such as Treatment-Resistant Depression (TRD), where individuals may fail to respond to traditional antidepressant treatments (e.g., psychotherapy, pharmacotherapy). Moreover, it may raise further concerns for an individual’s motivation to consent and the level of understanding of the treatment or research procedure. This paper focuses on the informed consent process for Vagus Nerve Stimulation (VNS) in the treatment of individuals diagnosed with TRD. Specifically, the paper addresses how depression may affect the decision-making capacity of an individual and the potential ethical and legal impact of failure to appreciate the seven elements of the consenting process (competence, voluntariness, disclosure, recommendation, understanding, decision, and authorization). To ensure the protection of vulnerable individuals with psychiatric disorders such as TRD and promote ethical behavior in biomedical research and patient care while avoiding potential legal pitfalls, we propose a paradigm that requires a stringent evaluation process of decision-making capacity for informed consent. (shrink)