The main effects of 8-week mindfulness-based programs (MBP) on anxiety and depression are now supported by reasonably robust evidence. However, few to no studies have looked at whether and how these main effects come to be over the course of the MBP. The goal of the present study was to look at how meditation practice predicted changes in well-being, and vice versa, at a weekly level, within an 8-week online MBP.

The participants were 457 Finnish upper secondary education students who underwent an 8-week online MBP. App-based ecological momentary assessment data were collected on how many minutes the participants meditated (daily) and their anxiety, happiness, and sleep problems (weekly). These data were analyzed using a longitudinal (nine time point) path model.

Participants’ weekly minutes of mindfulness meditation were a consistent, albeit weak, predictor of decreases in anxiety and increases in happiness. During the course of the study, answer rates declined from 75.7% (Time 0) to 27.4% (Time 8) for anxiety, happiness, and sleep and from 80.5% to 37.0% for meditation minutes.

Results suggest well-being improvement from mindfulness meditation is an ongoing process and that ecological momentary assessment is a promising methodology for studying it.