Transcranial Direct Current Stimulation (tDCS) in the Treatment of Major Depressive Disorder (MDD)
Condition: Major Depressive Disorder
MeSH terms: Depressive Disorder; Depression; Depressive Disorder, Major
Study type: Interventional

Summary: 
      The project will investigate the use of a novel neuromodulatory technique, transcranial
      direct current stimulation (tDCS) in the treatment of patients with major depressive
      disorder.

      Hypothesis 1: Active tDCS will improve depressive symptomology to a significantly greater
      degree than sham treatment.

      Hypothesis 2: Active tDCS will be well tolerated and free of major side effects.
    

Detailed description: 
      Major depression is a disorder with major clinical and economic significance locally and
      internationally. It is a disorder of high prevalence and results in substantial disease
      burden and health-care costs. Critically, a significant percentage of patients, usually
      estimated at around 30%, fail to respond to standard treatments (Fitzgerald 2003).
      Techniques, such as repetitive transcranial magnetic stimulation (rTMS), are being
      investigated widely for the treatment of this disorder, with considerable success in recent
      years (Fitzgerald, Benitez et al. 2006; Hasey 2001). However, TMS equipment is expensive and
      requires specialized application. Additionally, TMS is associated with some side-effects
      (e.g. seizures). Given that depression occurs in all cultures and countries, there would be
      considerable value in developing a low-cost, non-invasive technique that can be applied in a
      wide variety of settings and which has already been shown to have some efficacy in MDD
      (Boggio et al. 2007).

      The proposed study will be a randomized, double blind, placebo-controlled (i.e., sham
      stimulation vs. active tDCS), longitudinal, treatment outcome trial. Individuals with MDD
      will be randomized to 1 of 2 treatment conditions. These will be:

        1. Active 2mA tDCS: in this condition, 1 stimulator will be used with anodal stimulation to
           the left prefrontal cortex and cathodal stimulation to the right prefrontal cortex. The
           placement of anodal stimulation is proposed to enhance activity in the left frontal
           cortex; the cathode aims to reduce activity in the right prefrontal cortex.

        2. Sham treatment: the system setup is identical to that of active tDCS, but the stimulator
           will be turned off after 30 seconds.

      A total of 15 treatments will be administered to all participants over 3 weeks (one per
      working day). Individuals will be randomized on a computer-generated list. Clinical raters
      and patients will be blind to the treatment condition. Clinical ratings well be conducted
      prior to and after the treatment course (i.e., after 3 weeks). All subjects randomized to
      sham treatment will be offered active treatment at the end of the acute treatment phase.
    

Intervention name(s): transcranial direct current stimulation (tDCS)
Intervention type(s): Device
Intervention description(s): Delivery of mild current to specified brain regions.
Other intervention name(s): Stimulator CX-6650 (Rolf Schneider Electronics, Germany)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: tDCS; transcranial direct current stimulation; major depression; double-blind; randomized; placebo-controlled; treatment