What is tDCS?
tDCS is short for transcranial direct current stimulation and refers to a therapy method by which a weak current stimulates certain areas of the brain. For example, it’s known that when a person is suffering from depression, the brain cells in a region of their frontal lobe are less active. Using electricity to stimulate this area of the skull from the outside activates the neurons and helps improve the patient’s condition.
Electrical stimulation for depression
Therapy with tDCS is currently being widely discussed and extensively researched for a range of applications, including as an alternative treatment for depression. It can be used when psychotherapy or antidepressants don’t achieve the desired results, for example. It’s also a conceivable substitute for traditional forms of therapy that are otherwise not possible if the patient suffers from an anxiety disorder.
What else can be treated with tDCS?
tDCS also has the potential to provide relief for other mental or neuronal disorders. These include migraine attacks, cognitive difficulties following a brain injury or the condition of patients in pain. The extent to which tDCS works in areas other than depression is still less well researched.
How transcranial direct current stimulation works
Transcranial direct current stimulation is carried out at home or in a clinic and in line with the doctor's instructions. After two pads have been positioned on the skull, a flow of electricity – just a few milliamperes – is activated for 20 to 30 minutes. This procedure is usually repeated five times a week, followed by a two-day break. Most patients show results after 3 to 4 weeks and the therapy can be gradually reduced.
Flow – a new device for tDCS
There are various devices available for treating patients with tDCS. One of the latest is available from Flow Neuroscience and is similar in shape to a headset. An app controls the electrical stimulation and also documents the success of the therapy.
Pros and cons of tDCS
tDCS is an inexpensive and easy-to-use therapy method that causes few side effects. The extent of its effectiveness in individual cases and the long-term consequences of the treatment are currently being researched. Some studies carried out in recent years on transcranial direct current stimulation have indicated a low to moderate antidepressant effect.
Are there side effects?
Itching or reddening in the area of the electrodes or pads is possible. Headaches, fatigue or non-specific discomfort may also occur. In general, patients treated in studies on tDCS did not report any significant side effects.
The effect of tDCS on depression
The aim of the stimulation is to help bring thoughts and feelings spiralling into negativity back under control. Typical symptoms of depression – such as tiredness, sleep disorders, difficulty concentrating or loss of appetite – are alleviated by activating the brain cells. Study participants treated with the therapy also reported improved mood, increased performance and less anxiety. With its electrical impulses, direct current stimulation tricks the brain, as it were, suggesting activity where there is none (yet).
When treatment isn't recommended
The treatment isn't recommended for people who have an implant in their brain or who have had other brain surgery. A pacemaker and pregnancy are also obstacles to treatment with electrostimulation.
Difference between tDCS and rTMS
In addition to tDCS, there are other non-invasive brain stimulation techniques such as repetitive transcranial magnetic stimulation (rTMS). In contrast to tDCS, rTMS generates electrical magnetic fields. Although the methods differ, both therapies have the same goal: to activate the brain cells in the prefrontal cortex.
What exactly is rTMS?
rTMS has been available as a treatment method for longer than tDCS and has been approved for over ten years as a treatment for people with severe depressive disorder who are otherwise resistant to therapy. tDCS is used more widely, including for people with mild to moderate depression who aren't necessarily resistant to medication and psychotherapy. Due to the mildness of its side effects, direct current stimulation is considered an interesting alternative. Another difference is the place of treatment: rTMS can only be performed in a clinic, while tDCS can be performed at home.
What research says
A meta-study from 2020 reviewed 18 studies with a total of 930 patients. Based on their analysis, the authors of this meta-study consider tDCS to be effective as a treatment method for depression. The method was therefore also classified as “definitely effective” according to international guidelines for the treatment of severe depression. In contrast, Ulm University Clinic found no demonstrable effect in a study published in 2023 and announced that it would continue to rely on the more complex rTMS method.