What’s in a mood? looking for dynamic predictors of individual improvement in depression

Many people are affected by depression at some point in their lives, but it is unfortunately not yet well understood who will experience improvement or recurrence of symptoms, and what predicts such symptom change. Both short-lived variations in emotions and sudden shifts in symptoms appear to be relevant in predicting a better prognosis for people’s depressive complaints, on average. However, it is unclear how these findings translate to the individual. Therefore, in this dissertation I investigated the way depression changes over time in individual patients, with a specific focus on the moment-to-moment fluctuations in mood that precede the recovery of symptoms during psychological treatment. We measured people intensively throughout the day, asking them repeatedly how they were feeling at a given moment. By collecting so many measurements per person we could study the changes in emotions these people experienced over the day, as well as map the trajectory of their symptoms over time. The studies in this dissertation show that the path to recovery from depression rarely follows a simple straight line. The odds of responding to treatment were higher for people who experienced sudden symptom improvements within their overall improvement trajectory, and stronger negative emotions in the week before treatment started. We also investigated whether we could detect any early warning signals before changes in symptoms (such as improvements during psychological treatment, or a recurrence of depressive symptoms). Some people showed such early warning signals, but these signals were not detected often enough to be useful for the clinical practice yet.