Enhance your depression treatment offering

Flow tDCS now offered by 5 NHS services and over 200 private practice clinics.


How does Flow work?

There is an association between lowered activity in the dorsolateral prefrontal cortex and depression.

Flow works by using tDCS (transcranial Direct Current Stimulation) to stimulate the brain and help restore activity, relieving depressive symptoms.

The headset is typically used 3-5 times a week by the patient at home, each session is 30 minutes.

Clinicians can monitor adherence and symptom change over time using Flow’s clinical software.

What is the evidence?

There are three main categories of evidence:

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RCT evidence for the efficacy and safety of tDCS

There are now over 20 large, high quality Randomised Controlled Clinical Trials (RCTs) in the literature. Several meta-analyses of these trials have concluded that there is class A evidence (meaning definite effect) for the ability of tDCS to improve depression.

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RCT evidence for Flow

In 2023 leading researchers from University of East London and Kings College ran a Randomised Controlled Clinical Trial (or RCT) which compared Flow to a placebo. Participants underwent 10 weeks of tDCS depression treatment using the Flow headset. Results showed that 57% went into remission (not clinically depressed) within 10 weeks, and there were no serious side effects connected to the use of the device.

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Real-world evidence for Flow

Flow’s tDCS device is now being used in the NHS across primary care, community mental health and perinatal mental health services. Northamptonshire Health Foundations Trust has published three papers supporting the use of Flow in the NHS.

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In addition, Flow has collected a considerable amount of real world data through the Flow app. The Flow app asks users to fill in a short medical questionnaire1 once per week so that they can track how their symptoms are changing over time. Analysis of aggregated questionnaire data from 4,000 users shows that 46% go into remission or response by week 10.

Approved for at-home use across the UK and EU

FDA Breakthrough device designation

FDA breakthrough device designation for at-home depression treatment


Approved by the British Standards Institution (BSI)


Class IIa medical device CE-marked. Approved for use in the EU and UK


Tested according to IEC 60601 for electrical medical device safety


Who is using Flow?

Flow is being used by 5 NHS services and over 200 private practice mental health clinics. These clinics are using Flow because:

1. It increases patient choice.

2. It can easily be combined with other treatment types.

3. It provides clinicians with another treatment option when others have failed.

4. It provides clinicians with a treatment option which can easily be used by the patient at home.

5. It delivers fast results.

6. There are no serious side effects associated with use of the device.

To read more about Flow in the NHS, head here.

To read more about Flow in private practice, head here.


Over 12,000 people have used the Flow tDCS device. Less than 5% have reported side effects.

This list includes known side effects from the Flow tDCS device (until August 2023):

  • Headache (~1.5 %)
  • Skin irritation (~1.2%)
  • Tinnitus (~0.6%)
  • Mild skin burn (~0.5%)
  • Worsening of symptoms (~0.4%)
  • Increased anxiety (~0.3%)
  • Skin redness (~0.15%)
  • Stinging (~0.07%)

The following conditions are not contraindications, but may require extra precautions – such as careful monitoring:

  • Pregnancy
  • Suicidal thoughts or thoughts of self harm
  • The patient's skull is not intact
  • The patient has a cranial or intracranial implant
  • Epilepsy or other seizures
  • Chronic skin conditions affecting the forehead, such as psoriasis
  • Bipolar disorder

There is no evidence to suggest that tDCS treatment could be harmful to use during pregnancy. The electric current targets the brain directly without affecting the hormonal or digestive systems, making tDCS a tempting option for treating depression during the peripartum period.

However, more large-scale controlled trials are needed before any definitive conclusions can be drawn.

Today, the option to use tDCS during the peripartum period should be carefully evaluated in each individual case.

Encouraging research results for tDCS during pregnancy:

2018 – Kurzeck et al: A systematic review concluding that the scientific evidence for tDCS during pregnancy is sparse but promising.

2019 – Vigod et al: A pilot randomised controlled trial showing promising results for tDCS during pregnancy. There were no serious adverse events.

2022 – Laurin et al: A systematic review including seven studies and 33 women. No serious adverse effects for the mothers or children.

Weeks 1-3: Includes 5 stimulation sessions a week, each 30 minutes long.

Weeks 4 and beyond: Includes 1-2 stimulation sessions a week, each 30 minutes long.

Patients usually see results within the first 3 weeks of treatment. The length of the treatment depends on depression severity and chronicity in each individual case. A recent RCT study showed that 57% of participants with moderate to severe depression reached remission within 10 weeks.

Clinicians can create custom schedules.

There is currently Level B evidence (probable effect) for the use of tDCS on several conditions. A few of these conditions are treated by targeting the same area as the Flow tDCS device – the left dorsolateral prefrontal cortex (DLPFC).

tDCS treatment usually targets the left DLPFC in:

  • Cognitive symptoms of Parkinson’s disease
  • Auditory hallucinations in Schizophrenia (however the cathode is placed differently – over the left temporoparietal area)

A minority of studies have used the left DLPFC as a target for the treatment of pain disorders.

tDCS treatment usually targets other brain areas in:

  • Alcohol addiction (usually the right DLPFC)
  • Epilepsy (cathode placed over the affected area)
  • Neuropathic pain (motor cortex)
  • Migraine (motor cortex)
  • Fibromyalgia (motor cortex)
  • Stroke rehabilitation (motor cortex)

Level C evidence

There is currently Level C evidence (possible effect) for the use of tDCS in:

  • Obsessive-Compulsive Disorder (targeting the pre−SMA)
  • Aphasia (various placements, some targeting Broca’s area)


There is promising and growing evidence for tDCS treatment of ADHD symptoms.

In 2022, a randomised, double-blind, controlled trial showed that at-home tDCS treatment significantly improved attention in 64 adult patients with ADHD. The treatment used the anode over the right DLPFC.

If the Flow treatment has proven helpful at week 10, we recommend to continue for 6-12 months to help maintain progress and prevent relapse.

The maintenance protocol is based on how the patient responds to the Flow tDCS treatment during the initial 10 weeks.

Patients with a high risk of depression relapse are recommended a slightly different protocol than patients with a low risk of relapse – a minimum of 12 months treatment instead of 6 months.

High risk factors include:

  • Childhood maltreatment (such as abuse, neglect, family violence)
  • Residual symptoms from the last depressive episode
  • A history of depressive episodes
  • Chronic physical or mental health disorders

The following factors may also increase the risk, but the scientific evidence proving their impact on relapse is not as strong:

  • An anxiety disorder.
  • Rumination – experiencing repetitive negative thinking or easily dwelling on negative feelings/thoughts.

Low risk of relapse patients are exempt from these risk factors.

You can read more here.

You can read the pre-read here. It is currently being peer-reviewed and will be published in 2024.

You can also hear Daniel our Chief Clinical Officer talking about the methodology and results in a webinar, here.


1 The MADRS-s questionnaire which is ten-item diagnostic questionnaire which mental health professionals use to measure the severity of depressive episodes in patients with mood disorders.