Patients with clinical diseases often present psychiatric conditions whose
pharmacological treatment is hampered due to hazardous interactions with the
clinical treatment and/or disease. This is particularly relevant for major
depressive disorder, the most common psychiatric disorder in the general
hospital. In this context, nonpharmacological interventions could be useful
therapies; and, among those, noninvasive brain stimulation (NIBS) might be an
interesting option. The main methods of NIBS are repetitive transcranial
magnetic stimulation (rTMS), which was recently approved as a nonresearch
treatment for some psychiatric conditions, and transcranial direct current
stimulation (tDCS), a technique that is currently limited to research scenarios
but has shown promising results. Therefore, our aim was to review the main
medical conditions associated with high depression rates, the main obstacles for
depression treatment, and whether these therapies could be a useful intervention
for such conditions. We found that depression is an important and prevalent
comorbidity in a variety of diseases such as epilepsy, stroke, Parkinson's
disease, myocardial infarction, cancer, and in other conditions such as
pregnancy and in patients without enteral access. We found that treatment of
depression is often suboptimal within the above contexts and that rTMS and tDCS
therapies have been insufficiently appraised. We discuss whether rTMS and tDCS
could have a significant impact in treating depression that develops within a
clinical context, considering its unique characteristics such as the absence of
pharmacological interactions, the use of a nonenteral route, and as an
augmentation therapy for antidepressants.