Depression, often referred to as the ‘common cold’ of mental illness affects 5.7% of all adults globally with only around one third of people receiving treatment due to issues including a lack of investment in mental health care, a lack of trained healthcare professionals and the social stigma associated with mental health disorders (source: World Health Organisation).

Scientific American reports on a new biological treatment option which does not involve medication. The new at-home brain stimulation device developed by Flow Neuroscience delivers a mild electrical current to the dorsolateral prefrontal cortex, a brain region associated with mood regulation. Traditionally, depression has been treated using antidepressant medications such as Selective Serotonin Reuptake Inhibitors (SSRIs) or psychological therapies like Cognitive Behavioural Therapy (CBT), so this device represents an alternative intervention. The method, known as transcranial direct current stimulation (tDCS), has been studied for over two decades but remains controversial.

Research on the effectiveness of tDCS is mixed. A 2023 study in The Lancet found no meaningful difference between tDCS and a placebo, while other trials have reported some improvement in depressive symptoms. The US government’s decision (via the Food and Drug administration agency) to approve the treatment relied heavily on a 2024 trial involving 174 participants. Those who used the headset for 30-minute sessions over ten weeks showed greater symptom relief (rated using a standardised scale called the Hamilton Depression Rating Scale, by a medical professional) than those in the control group. The agency concluded that, although the benefits are modest, they outweigh the risks, which include headaches and skin irritation.

Researchers in the field remain very cautious, emphasising that the evidence base is inconsistent and that long-term effectiveness is yet to be established. The headset will be available to adults with moderate to severe depression and will cost $500–$800 (between £370 and £600). In the UK, the device is available to buy on the high street with the NHS currently running a pilot scheme of the device.

References:

World Health Organisation factsheet: Depressive disorder (depression) https://www.who.int/news-room/... (accessed 23.3.26)

U.S. Approves First Device to Treat Depression with Brain Stimulation at Home https://www.scientificamerican... (accessed 23.3.26)

Image credit Flow Neuroscience: https://www.flowneuroscience.c... (accessed 23.3.26)

UK pilot: https://www.flowneuroscience.c... (accessed 23.3.26)

ANSWER THE FOLLOWING QUESTIONS!

1. Explain why a psychologist might argue that using a brain-stimulation headset to treat depression is an example of biological reductionism.
2. The Flow device allows patients to treat their depression at home rather than attending a hospital. Discuss one or more implications for the economy if this at-home treatment proves effective.
3. In clinical trials for the Flow device, researchers used fMRI scans to measure brain activity and rating scales (1–10) to measure mood. Compare the validity of these two methods.
4. If you were conducting a piece of research into the effects of tDCS on symptoms of depression, which type of hypothesis would be most appropriate? Justify your decision with reference to this piece of research.
5. Which inferential test would be suitable to assess the effectiveness of tDCS in the 2024 trial?