Home-based transcranial direct current stimulation for the treatment of major depressive disorder

This study is for adults aged 18 and over who have been feeling depressed for at least two weeks. You can be taking antidepressant medication or having talking therapy, but you'll need to have been on the same treatment plan for at least six weeks before joining. If you're not currently receiving any treatment for your depression, you can also take part. You must be registered with a GP in England or Wales and be happy for us to contact them about your involvement in the study.

There are some reasons why you might not be able to join. For example, if you have a high risk of suicide or another significant mental health condition (like obsessive-compulsive disorder) that is your main concern. Also, if you use certain medications daily that affect how your brain works, or if you use illicit drugs or have heavy alcohol use, you might not be eligible. If you've had other types of brain stimulation treatments (like ECT or TMS) in the past, or have certain medical or brain conditions (like dementia or implants in your brain), you won't be able to participate.

If you decide to take part, your involvement in the study is expected to last up to 10 months. This includes some initial checks and then 9 months for the study itself, with a final check-in to see how you're doing.

At the start, you'll be randomly put into one of two groups: either the tDCS group or the 'usual care' group. Being 'randomly allocated' means it's like flipping a coin – you won't get to choose which group you're in. If you're in the usual care group, you'll continue with the treatments your GP or psychiatrist has prescribed for your depression, but you won't receive the tDCS treatment. If you're in the tDCS group, you'll receive the active tDCS treatment in addition to your usual care.

The first part of the study lasts 10 weeks. If you're in the tDCS group, you'll have tDCS sessions for 30 minutes, five times a week for the first three weeks, then three times a week for the next seven weeks, making a total of 36 sessions. You'll do these sessions at home, and for your very first session, a researcher will supervise you either by video call or in person if you prefer and can visit a local research site. We'll have appointments with you during this time at 1, 4, 7, and 10 weeks, and then again at 4 and 6 months after the study starts. Between week 10 and these follow-up visits, the tDCS group can choose to continue with tDCS sessions (3 times a week) if they wish, alongside their usual care.

In the second part of the study, after 6 months, everyone will be offered the active tDCS treatment if they'd like to try it. If you were in the usual care group and your depression hasn't improved, you can start tDCS. If you were already in the tDCS group, you can continue with up to three sessions a week for another three months. We'll then have a final check-up with you 3 months later, which will be 9 months from when you first joined the study. After this, your participation will be complete.