PRADAM

• Research type

  Research Study

• Full title

  Predicting Relapse After Discontinuing Antidepressants using Acute Tryptophan Depletion and Magnetoencephalography

• IRAS ID

  365238

• Contact name

  Quentin Huys

• Contact email

  q.huys@ucl.ac.uk

• Sponsor organisation

  University College London

• Clinicaltrials.gov Identifier

  Z6364106/2025/11/64 , UCL Data Protection Registration number

• Duration of Study in the UK

  3 years, 0 months, 1 days

• Research summary

  Many people experience a relapse of depression if and when they stop their antidepressant medication. We do not know how stopping antidepressants leads to depression returning. We also do not know who will have a relapse if they stop their medication. This study aims to understand this better.
  The study has three key aspects. First, the study will use behavioural and brain measurements (magnetoencephalography; MEG). Second, the study will look at the effect of briefly lowering serotonin through a dietary manipulation (acute tryptophan depletion; ATD). The hope is that the temporary reduction in serotonin ‘simulates’ what happens when antidepressants are stopped, and that looking at brain function at this time might help us understand how stopping antidepressants results in relapse. Third, the study will work with people who had depression but are now well and who are still taking an antidepressant medication but would like to stop. Participants will undergo brain imaging and ATD before stopping their medication, and will then be monitored for a relapse of depression for six months. This way, the relationship between lowering serotonin on brain function and the relapse after stopping antidepressants can be better understood.

  Importantly, the study has been assessed by the sponsor as being a non-CTIMP study because the intervention is not medicinal and cannot be related to the clinical outcomes (relapse) due to the within-subject design. The intervention has only temporary, transient effects on physiology and no value as a treatment in itself, and is not used with the intent of providing or assessing any treatment value.
  Ultimately, the hope is that the measurements could help us predict in advance who will relapse, and help manage this to avoid relapses.
  

• REC name

  East Midlands - Leicester South Research Ethics Committee

• REC reference

  26/EM/0044

• Date of REC Opinion

  1 Apr 2026

• REC opinion

  Further Information Favourable Opinion