Adults with severe forms of depression should consider non-surgical brain stimulation as an alternative or add-on treatment, according to a new study published in The BMJ.

Severe depression is a debilitating illness, and many patients find that the typical drug treatments and psychological therapies do not work for them. Although guidelines already support the use of brain stimulation, these techniques tend to be used too little and too late, and previous research into their effectiveness has been limited.

Non-surgical brain stimulation techniques, such as electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS), use electrical currents or magnetic fields to change brain activity. While researchers are not entirely sure how these treatments work, rTMS is thought to change activity in areas of the brain that are under or overactive in depression.

For the study, a research team led by Julian Mutz at the Institute of Psychiatry, Psychology & Neuroscience at King’s College London, set out to compare response (clinical efficacy) and all cause discontinuation (acceptability) of non-surgical brain stimulation for the treatment of major depressive episodes in adults.

They analyzed the results of 113 clinical trials involving 6,750 patients (average age 48 years; 59% women) with major depressive disorder or bipolar depression. The patients were randomized to receive 18 active treatment strategies or inactive (“sham”) therapy.

Active techniques included ECT; rTMS; magnetic seizure therapy; and transcranial direct current stimulation (tDCS). Each trial was also scored as having low, high or unclear risk of bias.

The most common treatment comparisons were high frequency left rTMS and tDCS versus sham therapy, whereas more recent treatments (such as magnetic seizure therapy and bilateral theta burst stimulation) remain understudied.

The researchers found that bitemporal ECT, high dose right unilateral ECT, high frequency left rTMS and tDCS, were more effective than sham therapy across all outcome measures in network meta-analysis.

For all active treatment strategies, patients were no more likely to discontinue treatment than when they received sham therapy. There were few differences in all cause discontinuation rates between active treatments.

The researchers point to some limitations. For example, several studies carried an unclear risk of bias, and a focus on short term effects meant results may not apply to the long term antidepressant effects of non-surgical brain stimulation. In addition, the study did not examine specific undesired side effects.

However, the researchers say their findings have implications for clinical decision making and research “in that they will inform clinicians, patients, and healthcare providers on the relative merits of multiple non-surgical brain stimulation techniques.”

Source: BMJ