High frequency strong current tACS：a new dawn of non-drug therapy for patients with major depressive disorder

A commentary on: Transcranial alternating current stimulation for treating depression: a randomized controlled trial. By Wang H, Wang K, Xue Q, et al . Brain. 2022;1451:83-91.doi:10.1093/brain/awab252. Major depressive disorder (MDD) is a common severe mental illness with recurring episodes. The most commonly used treatment is drug therapy, which is associated with a series of side effects and has an efficacy rate below 50%.1 Non-invasive brain stimulation technique has been gradually applied in clinical practice. Transcranial alternating current stimulation (tACS), a form of non-invasive brain stimulation, is a light, wearable piece of equipment for cortical stimulation. It modulates cortical excitability and spontaneous brain activity by applying an electric current to the scalp, generating an alternating current that flows through the specified area between the stimulation electrodes. A recent study published in Brain proved the clinical potential of tACS stimulation for patients with MDD. The study investigated the clinical safety and efficacy of tACS in first-episode, drug-naive patients with MDD. The results showed that patients who received 20 daily 40 min, 77.5 Hz, 15 mA, one forehead and two mastoid sessions of active stimulation over four consecutive weeks achieved significantly higher remission rates than those who received sham stimulation. In addition, tACS treatment alleviated the depression state with lasting effects shown in 4 weeks of follow-up measurements; only some mild treatment-emergent adverse events were reported.2 This is consistent with previous reports that tACS is associated with fewer …