The International Journal of Neuropsychopharmacology

Thematic Section: New Aspects in the Treatment of Affective Disorders

A double-blind, sham-controlled trial of transcranial direct current stimulation for the treatment of depression

Colleen K. Looa1a2a3 c1, Perminder Sachdeva1a4, Donel Martina1a3, Melissa Pigota1a3, Angelo Alonzoa1a3, Gin S. Malhia5, Jim Lagopoulosa5 and Philip Mitchella1a3

a1 School of Psychiatry, University of New South Wales, Sydney, Australia

a2 St George Hospital, South Eastern Sydney Illawarra Health Service, Australia

a3 Black Dog Institute, Sydney, Australia

a4 Neuropsychiatric Institute, Prince of Wales Hospital, Randwick, Sydney, Australia

a5 Discipline of Psychological Medicine, University of Sydney, Sydney, Australia

Abstract

Two recent sham-controlled studies found that transcranial direct current stimulation (tDCS) was an effective treatment for depression. As tDCS is painless, relatively safe and inexpensive, its efficacy in treating depression warrants further investigation. This double-blind, randomized study tested tDCS at the same stimulation parameters as a previous positive study (1 mA current strength, five treatment sessions, active or sham, given on alternate days) in 40 depressed participants. Anodal stimulation was centred over the left dorsolateral prefrontal cortex, with the cathode placed on the lateral aspect of the contralateral orbit. tDCS was continued up to a total of ten active sessions per participant. Mood outcomes were measured by psychiatrist raters blind to treatment condition using the Montgomery–Asberg and other depression rating scales. Psychomotor speed was assessed immediately before and after a single tDCS session and attention, frontal executive function, working memory and verbal learning were assessed after each group of five sessions. Overall depression scores improved significantly over ten tDCS treatments, but there was no between-group difference in the five-session, sham-controlled phase. tDCS was found to be safe, with no adverse effects on neuropsychological function, and only minor side-effects. It is recommended that the efficacy of tDCS in depression be further evaluated over a longer treatment period, using enhanced stimulation parameters.

(Received January 04 2009)

(Reviewed June 16 2009)

(Revised June 24 2009)

(Accepted July 10 2009)

(Online publication August 12 2009)

Correspondence:

c1 Address for correspondence: Associate Professor C. K. Loo, Level 2, James Laws House, St George Hospital, Kogarah, NSW 2217, Australia. Tel.: 61-2-9113-2039 Fax: 61-2-9113-3734 Email: colleen.loo@unsw.edu.au