Deep-brain stimulation has been used to treat advanced Parkinson disease and other neurological and psychiatric disorders that have not responded to other treatments. While deep-brain stimulation can modulate overactive or underactive regions of the brain and thereby improve motor function, it can also cause changes in a patient’s thought and personality. This paper discusses the trade-offs between the physiological benefit of this technique and the potential psychological harm.

Advances in psychopharmacology raise the prospects of enhancing neurocognitive functions of humans by improving attention, memory, or mood. While general ethical reflections on psychopharmacological enhancement have been increasingly published in the last years, ethical criteria characterizing physicians’ role in neurocognitive enhancement and guiding their decision-making still remain highly unclear. Here it will be argued that also in the medical domain the use of cognition-enhancing drugs is not intrinsically unethical and that, in fact, physicians should assume an important role in gating (...) their usage. For finding normative orientation, concepts of disease, normality or medicine will not be helpful since—due to their cryptonormative nature—they rather hamper than allow targeted discussion and decision-making. As an alternative, the common and widely accepted bioethical criteria of beneficence, non-maleficence, autonomy and distributive justice allow a clinically applicable, highly differentiated context- and case-sensitive approach. By embedding decision-making in a participative physician–patient relationship extrinsic objections against neurocognitive enhancement (e.g. invalid perceptions about efficacy, benefit or risk; questionable voluntariness; restrained decision-making capacity) can be curtailed. (shrink)

Deep brain stimulation (DBS) to different sites allows interfering with dysfunctional network function implicated in major depression. Because a prominent clinical feature of depression is anhedonia--the inability to experience pleasure from previously pleasurable activities--and because there is clear evidence of dysfunctions of the reward system in depression, DBS to the nucleus accumbens might offer a new possibility to target depressive symptomatology in otherwise treatment-resistant depression. Three patients suffering from extremely resistant forms of depression, who did not respond to pharmacotherapy, psychotherapy, (...) and electroconvulsive therapy, were implanted with bilateral DBS electrodes in the nucleus accumbens. Stimulation parameters were modified in a double-blind manner, and clinical ratings were assessed at each modification. Additionally, brain metabolism was assessed 1 week before and 1 week after stimulation onset. Clinical ratings improved in all three patients when the stimulator was on, and worsened in all three patients when the stimulator was turned off. Effects were observable immediately, and no side effects occurred in any of the patients. Using FDG-PET, significant changes in brain metabolism as a function of the stimulation in fronto-striatal networks were observed. No unwanted effects of DBS other than those directly related to the surgical procedure (eg pain at sites of implantation) were observed. Dysfunctions of the reward system--in which the nucleus accumbens is a key structure--are implicated in the neurobiology of major depression and might be responsible for impaired reward processing, as evidenced by the symptom of anhedonia. These preliminary findings suggest that DBS to the nucleus accumbens might be a hypothesis-guided approach for refractory major depression. (shrink)

In this article we will draw on experiences from our own research on deep brain stimulation of the central thalamus in the minimally conscious state. We describe ethical challenges faced in clinical research involving medical devices and offer several cautionary notes about its funding and the interplay of market forces and scientific inquiry and suggest some reforms.

Deep brain stimulation (DBS) is currently in pivotal trials as an intervention for treatment-resistant depression (TRD). Although offering hope for TRD, DBS also provokes ethical concerns—particularly about decision-making capacity of people with depression—among bioethicists, investigators, institutional review boards, and the public. Here, we examine this critical issue of informed consent for DBS research using available evidence regarding decision-making capacity and depression. Further, we explore the implications of the nature of TRD as well as that of the intervention (invasive brain surgery) (...) for informed consent. Based on these analyses, we argue that additional safeguards specific to DBS research for TRD, beyond those that might be used in any higher risk study, are not supported by available empirical evidence. We nevertheless underscore the limited data on such invasive procedures in severely ill psychiatric patients and advocate a research agenda for the systematic study of ethical issues raised by these research endeavors. (shrink)