The Flow Headset (£399) is one (if not the only) device I know that is clinically approved in the UK to treat stress and depression.
So, Lottie Winter, a mental health advocate, gives her (mostly positive) review of the device - from initial opening to first use.
"Flow is the first at-home device that has been approved in the UK and EU for treatment of major depressive disorder. And it's medication-free."
"The reason why (tDCS) is effective in treatment of depression is because people with depression often have an under-active frontal cortex."