Examining Duration of Transcranial Direct Current Stimulation Sessions for Depression

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Participants in the 30-minute group showed a significantly greater percentage improvement than those in the 20-minute group.
Participants in the 30-minute group showed a significantly greater percentage improvement than those in the 20-minute group.

Twenty or 30 minutes of transcranial direct current stimulation (tDCS), combined with sertraline therapy, was effective in treating mild and moderate depression, according to results from a study published in Progress in Neuro-Psychopharmacology & Biological Psychiatry. The benefits of 30 minutes of tDCS exceeded the benefits obtained from 20 minutes.

It is known that tDCS can be an effective treatment for depression, therefore researchers undertook this study to investigate the optimal duration of the stimulation sessions.

The study randomly assigned 69 right-handed patients with mild to moderate depression (mean age 37.6 ± 10.5) to 3 groups based on treatment duration: 30-minute, 20-minute, or sham tDCS. Treatment consisted of 10 daily sessions of anodal or sham tDCS of the left dorsolateral prefrontal cortex (0.5 mA; electrode 3.5×7 cm), combined with 50 mg/day of sertraline. Mood, cognition, and brain-derived neurotrophic factor levels were evaluated before and after the treatment.

The researchers observed a significant difference between groups in the percent change on the Hamilton Depression Rating Scale (mean change: -54.5%; F(2, 66)=10.1; P =.0002). Compared with the 30-minute group (63.8%±13.4; 95% CI, 11.23-29.44; P =.00003) and the 20-minute group (53.2%±15.3; 95% CI, 0.21-19.26; P =.045), the sham group showed a smaller improvement (43.4%±18.1).

Participants in the 30-minute group showed a significantly greater percentage improvement than those in the 20-minute group (95% CI, 1.74-19.46; P =.02).

The 30-minute group was also superior to the 20-minute and sham groups in percentage of responders (89%, 68%, and 50%, respectively) and remitters (70%, 27%, and 35%, respectively).

Among the neuropsychological tests conducted, only the Digit Span Backwards test showed a significant interaction between groups (TIME*GROUP; F(2, 65)=6.6, P =.002), with a greater improvement in both active groups compared with the sham group (P <.05).

There was no significant change in brain-derived neurotrophic factor level between the groups after treatment.

“The study has demonstrated significant augmenting effect of 30 or 20 minutes of tDCS on low-dose sertraline treatment of depression,” the researchers commented.

However, “categorical variables benefited from tDCS only in the 30-minute group,” they observed. Additionally, “[the] 30-minute group had significantly greater improvement in mood and greater proportion of remitters compared [with] the 20-minute group.”

They concluded that the treatment was “effective…for depression relief in mild and moderately depressed right-handed patients.”

Reference

Pavlova EL, Menshikova AA, Semenov RV, et al. Transcranial direct current stimulation of 20- and 30-minutes combined with sertraline for the treatment of depression [published online December 9, 2017]. Prog Neuropsychopharmacol Biol Psychiatry. doi:10.1016/j.pnpbp.2017.12.004

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