Chronic pain is common but often difficult to control because the effectiveness of a given medication varies across individuals, and the pain experienced can vary dramatically from day to day. Helping patients and clinicians define which treatments work best is important for ensuring that patients use the safest pain medications at the lowest effective dosage, in combination with non-drug based interventions.


To help address this challenge, UC Davis is leading a research project funded by the National Institutes of Health to design and test ‘Trialist’; a mobile app that can guide patients and their clinicians in conducting ‘N-of-1 studies‘ to determine which of two treatments is most effective for their chronic pain. The app will be developed using the Open mHealth platform and will allow patients to compare both drug treatments, such as Ibuprofen or Oxycontin, and non-drug treatments, such as yoga and meditation.

Throughout the development of Trialist, both patients and clinicians were regularly involved in research focus groups, to ensure the product met both users’ needs. The app is now being piloted through a randomized trial of 244 chronic pain patients. The software that has been developed for Trialist will be open-sourced, to enable others to take advantage of the ‘n-of-1′ and analysis module in new applications, and across further clinical domains.


Trialist has both desktop and a mobile (Android & iOS) components; the desktop component allows a clinician and patient to collaborate to choose which treatments they want to compare (e.g., ‘Treatment A’ and ‘Treatment B’) and then to set up how long (e.g., 1-2 weeks) and how many times (e.g., 2 to 4 times per day) the patient will take each treatment. The app, used by the patient, then randomizes the order in which the patient takes each treatment. It also guides a patient to take their assigned treatments at the correct time, and prompts them to report their pain symptoms and side effects.

Once the patient has completed the cycles of different treatments, the symptom and side effect data is analyzed, and the patient and clinician provided with results of the ‘N-of-1′ study, providing statistical indication of whether Treatment A or Treatment B was more effective at controlling their pain, along with the burden of any side effects.

The following researchers are co-investigators on this project:

  • Principal Investigator: Richard Kravitz, UC Davis
  • Ida Sim, UCSF
  • Deborah Ward, UC Davis, School of Nursing
  • Barth Wilsey, Sacramento VA
  • Christopher Schmid, Brown University
  • Marc Schwartz