The makers of a device that delivers small electrical impulses to the brain are hailing the technology as a groundbreaking mental health treatment, but others are sceptical

“Flow helps the vast majority of people to improve their depression,” reads the latest marketing email from Flow Neuroscience, a Swedish-based company that has been making headlines over the past year with what it describes as an “innovative brain-stimulation treatment” that patients can use in their own homes.

Flow’s users receive a headset that delivers small electrical pulses to an area in the front of the brain called the dorsolateral prefrontal cortex, which is linked to decision making, motivation, planning and working memory, functions that become impaired in depression.