Transcranial direct current stimulation

Kuruppuarachchi & Wijeratne (2004) support the use of innovative and cheaper treatments for depression in developing countries. In Brazil, for instance, antidepressants are scarcely available in the public sector and the delivery of these drugs is irregular, hence hindering long-term treatment. A recent study showed that only 17% of primary care patients with current depressive disorder in Brazil received any treatment for their depression. In comparison, 49% and 34% of patients with similar conditions in Australia and the USA, respectively, received treatment for depression (Simon et al, 2004). The main reason for this disparity is the lack of resources in poor countries. We therefore propose that a type of brain stimulation—transcranial direct current stimulation (tDCS) – may be a satisfactory alternative to increase access to adequate antidepressant treatment.

Electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) are examples of brain stimulation therapy that are effective in treating depression. However, these treatments are expensive and might be associated with adverse effects (Hasey, 2001). In recent years, a simple technique of brain stimulation that seemed long forgotten has received renewed attention – tDCS. This treatment is inexpensive, easy to administer, non-invasive and painless (Nitsche et al, 2003). There are few past reports of tDCS in treating depression (Lolas, 1977). However, at the time of those trials much less was known about the methodological aspects and physiological effects of tDCS and the results were quite variable.

Preliminary, unpublished data from a randomised, sham-stimulation controlled and double-blind trial evaluating the effects of anodal stimulation of the left dorsolateral prefrontal cortex in people with depression suggest that tDCS is an effective treatment for major depression (further details available from the authors on request).

Thus, we have come to believe that tDCS might be a reasonable alternative treatment for depression in low- and middle-income countries. The device to deliver tDCS is simple, can cost less than US$100 00 and can be manufactured locally. The equipment is fully reusable and utilises one standard battery that can last several weeks. Furthermore, this treatment is easy to administer, and can be applied by technicians following appropriate instruction and training. Although further studies evaluating this method are warranted, tDCS might help to improve mental health in areas with poor resources.