Transcranial Direct Current Stimulation: Considerations for Research in Adolescent Depression

Abstract

Adolescent depression is a prevalent disorder with substantial morbidity and mortality. Current treatment interventions do not target relevant pathophysiology and are frequently ineffective, thereby leading to a substantial burden for individuals, families, and society. During adolescence, the prefrontal cortex undergoes extensive structural and functional changes. Recent work suggests that frontolimbic development in depressed adolescents is delayed or aberrant. The judicious application of non-invasive brain stimulation techniques to the prefrontal cortex may present a promising opportunity for durable interventions in adolescent depression. Transcranial direct current stimulation (tDCS) applies a low-intensity, continuous current that alters cortical excitability. While this modality does not elicit action potentials, it is thought to manipulate neuronal activity and neuroplasticity. Specifically, tDCS may modulate N-methyl-d-aspartate receptors and L-type voltage-gated calcium channels and effect changes through long-term potentiation or long-term depression-like mechanisms. This mini-review considers the neurobiological rationale for developing tDCS protocols in adolescent depression, reviews existing work in adult mood disorders, surveys the existing tDCS literature in adolescent populations, reviews safety studies, and discusses distinct ethical considerations in work with adolescents.

Neuroethics of neuromodulation: An update

“…Yet Johnco and Storch[40] note the lack of a standardized definition of “refractory” when considering DBS or other neurodevices, and that the use of invasive neuromodulation in pediatric populations is in need of more thorough clinical and ethical analysis. The articles discussing pediatric DBS note concerns about the scarcity of clinical studies and data with minors, including little information about long-term effects, concerns about safety and informed consent, potential effects on agency of developing minors, and the use of neuromodulation tools to attempt to enhance healthy children[40] [41] [42] [43] [44] [45] [46] [47] [48] [49]. …”

“…While most studies cite that tDCS has been found to be safe in adults, little evidence is available to prove the safety or effectiveness of electrical stimulation on a developing brain; this is particularly concerning because many of these devices are available for sale online[43] [44] [45] [46] [50] [51]. Wagner and colleagues surveyed 227 individuals about their attitudes and willingness to use tDCS to enhance a 10-year old child’s cognitive abilities, finding that the majority oppose a potentially harmful intervention if it is not medically necessary.…”

Indices of Change, Expectations, and Popularity of Biological Treatments for Major Depressive Disorder between 1988 and 2017: A Scientometric Analysis

“…The WHO (2018) reported that less than half of those were depressed, and in some countries less than 10% received treatment [5]. Untreated MDD has far-reaching consequences as it leads to work-related disability and productivity loss which result in adverse effects on quality of life, incurring significantly higher indirect costs to the society [6,7,8,9].…”

A pilot study of GABAB correlates with resting-state functional connectivity in five depressed female adolescents

“…At least 30% of adolescents with depression attempt suicide during the course of their illness (Cousins and Goodyer, 2015). Currently, investigational neurostimulatory approaches are only considered for adolescents after medical management has failed (Lee et al, 2017; McIntyre et al, 2014).…”