Transitions in Depression (TRANS-ID) Recovery: Study protocol for a repeated intensive longitudinal n = 1 study design to search for personalized early warning signals of critical transitions towards improvement in depression

Aim. The Transitions in Depression (TRANS-ID) Recovery study has gathered intensive longitudinal data in a group of individuals with depression during psychological therapy.The study was designed to gather high-resolution time series to monitor individual change processes in great detail, to allow for personalized predictions of shifts in depressive symptoms.

Method. The data collection combined experience sampling methods to assess momentary affect and behavior (five 27-item questionnaires a day, for four months), ambulatory assessment of physical activity and heart rate (continuous, for four months), and depression symptom assessments (weekly for six months, and monthly for the six months thereafter, twelve months total). In addition to a baseline diagnostic interview, baseline questionnaires covered a range of constructs, including overall psychopathology symptoms, medication use, psychological treatment history, alexithymia, life events, quality of life, and chronotype. After the four-month ambulatory assessment period, a personal report of the experience sampling data was given to each participant, and a semi-structured qualitative interview was conducted to evaluate participants’ own retrospective experience of symptom changes during the research period.

Conclusion. The TRANS-ID Recovery study procedures and materials are described in detail in this document. The study protocol was approved by the Medical Ethical Committee of the University Medical Center Groningen (reg. number: NL58848.04.16).