Flow is an alternative treatment for depression which is being trialled by the NHS and is already available from more than 100 clinics.
Flow uses a non-invasive brain stimulation technique – transcranial direct current stimulation (tDCS) – to target the left dorsolateral prefrontal cortex, which is the area of the brain controlling key cognitive skills such as emotional expression and is most associated with depression.
Health Tech World sat down with Flow Neuroscience CEO Erin Lee over Zoom to learn more about the technology and Flow’s ambitions in mental health, dementia and beyond.
Hi Erin. What attracted Flow Neuroscience’s founders to the mental health space?
Our co-founder Daniel is a clinical psychologist. A lot of it came from his own lived experience of working with patients with depression every day and seeing first hand how inadequate much of the treatment is.
What is shocking to me is that depression is expected to be the leading cause of disease burden by the end of this decade.
80 per cent of people who are treated for depression are given some sort of pill. But studies show that antidepressants only work for about 30 per cent of people, often less, and many more people have side effects.
For many folks, antidepressants can be life saving. But if you’re one of the majority that they don’t work for, you have very limited options.
Fundamentally, that was the impetus behind Flow: Can we treat depression in a better, more effective way?
How does the Flow headset work and how does it differ from similar treatments like TMS?
Flow uses a technology called transcranial direct current stimulation, or tDCS. It’s a very mild form of electrical current.
We target the left dorsolateral prefrontal cortex, which is the area of the brain associated with mood.
When you look at scans of depressed brains, you’ll see lower activity in this region.
So we target that area with an electrical current to gently stimulate those areas to fire, increasing activity and reducing depressive symptoms.
Erin Lee
TMS has a very similar mechanism of action. It’s much stronger, so you have to do it in the clinic.
It’s a very expensive treatment, but because it’s so strong, it immediately causes the neurons to fire whereas we’re sort of nudging them.
So the mechanism of action is very similar, but cost and accessibility are very different.
What does the treatment timeline look like? When can patients expect to see benefits?
There are two core parts to it. The first is the intensive three week treatment protocol that is 30 minutes a day, five times a week, for 15 sessions.
Then you move into the maintenance period, which can be anywhere from three to nine months, 30 minutes a day, two to three times a week.
This depends on the individual, their history with depression and various other factors.
We’ve found that 82 per cent of our users will see results in the first three weeks, and then that maintenance allows them to continue to see results and often improve.
What about the long-term impact?
It has this same longevity as you see with antidepressants and even TMS.
Again, a lot of it will depend on the demographic and their history with depression.
Obviously some folks are harder to treat, but it’s on par with other treatments, which I think is surprising for a lot of people.
Where is Flow being used on the NHS today? What have you learned so far?
Flow is now available in four trusts, soon to be six.
We started in Northamptonshire and extended to Leicester. We partnered with NHS Practitioner Health which provides care to NHS clinicians.
We started with a population within community mental health, so, again, the very ill, acute depression cases.
We saw results in line with our trials, with 50 per cent of people reaching remission.
We also saw a 75 per cent reduction in suicidal ideation, which means lower secondary care and inpatient demand, which also helps the broader healthcare ecosystem.
From community mental health, we moved into postpartum, postnatal care, as well as elderly, co-morbid patients. So there really has been quite a bit of demand.
Presumably there are some quite significant wider benefits to this as well.
I think that’s what people often underestimate.
When patients first see the device, their initial reaction is often, ‘Okay, it’s $500, while a drug only costs $10.’ But that $10 isn’t the full picture. It’s a monthly cost, and often, the first drug doesn’t work.
That means multiple appointments to try alternatives, dealing with side effects like weight gain, sexual dysfunction, and interactions with other medications—all of which require additional visits.
In contrast, studies show that low users have 53 per cent fewer appointments. Clinicians can monitor progress remotely, ensuring adherence and improving outcomes.
When patients succeed, it not only benefits them but also frees up valuable healthcare resources, reducing the strain on secondary care.
After all, neither patients nor clinicians want to keep returning due to ineffective treatments. That’s a major advantage of this approach.”
Is there potential to apply the technology to other mental conditions?
Absolutely.
We’re already kicking off our study on bipolar depression, following a highly positive pre-study. We’re also seeing exciting progress in areas like pain memory and early dementia.
Naturally, when people hear this, their first reaction is, ‘How can it work for so many different conditions?’ It sounds too good to be true. And if it does work, why isn’t it already widely used?’
The key thing people often overlook is that the brain runs on electricity—that’s its fundamental language.
So it’s not surprising that different neurological conditions can respond to electrical treatment.
What is surprising is how much our ability to precisely target brain regions non-invasively has improved. Our understanding of the brain has evolved, as has our knowledge of proper dosing.
At the same time, there’s a growing demand for non-pharmaceutical treatments, which has driven more investment and innovation in this space.
It’s really a combination of all these factors coming together
What are your goals for 2025 and beyond?
Our goal remains accessibility.
In the short term, that means continuing our partnership with the NHS in the UK—demonstrating success both for patients and the healthcare system while ensuring the technology is affordable and available to everyone who needs it.
Some people can purchase it over the counter, but others can’t, and we want to make sure no one is left behind. It’s truly a win-win.
Beyond the UK, we’re also looking to expand into new regions, including the Middle East and the Far East, with plans for a U.S. launch by the end of the year.
