In this randomized controlled pilot study effects of a brief web-based mindfulness training on distress, perceived stress, mindfulness, mood and emotion regulation were investigated. Trends with medium effects in ITT and larger effects in per-protocol analysis suggest that a web-based mindfulness training may be effective in reducing perceived stress and improving negative affect.
In ITT we found medium, but non-significant effects for perceived stress (PSQ) and negative affect (PANASneg). Interaction effects might have been influenced by baseline differences between groups, increasing overall variance. For mindfulness (FMI) and emotion regulation (SEK-27) there were non-significant, but small effects. Otherwise there were no trends or significant interaction effects in the ITT-analyses.
Despite methodological concerns [45
], per-protocol analyses were performed, because we were also interested in the effects of the training when used regularly. The per-protocol analyses included persons who participated at least 50% of the training. This criterion was chosen, because it included persons who participated in both training modules. It has been postulated that only regular practice will result in changes of mindfulness [4
]. This also corresponds with study results on neurobiological changes related to mindfulness exercise [46
]. With persons participating at least for 6 days, the training showed to be effective for perceived stress (PSQ) and for negative affect (PANASneg
) with larger treatment effects, and trends with medium effects for positive affect (PANASpos
). Effects for PSQ are similar to stress reduction effects in a face-to-face mindfulness training in a community samples [47
In most studies using the BSI as a measure of distress, significant changes are reported [48
]; however, this was not the case in our study, with the exception of PSQ. In this respect it must be taken into consideration that the PSQ, which showed a medium effect in ITT and larger effect for per-protocol, is related to daily hassles and stress perception, while the BSI asks for symptom distress. Although there has been no evidence that shorter mindfulness trainings are less effective in reducing distress [13
], it seems possible that subjective changes in distress were noticed only by those with higher initial levels of GSI. When conducting subgroup analyses for the treatment-group, participants with higher GSI at the beginning of the training reduced GSI scores more than participants with lower initial GSI. Higher distressed persons reduced on average by 6 T-values. It is also interesting to note, that current literature states that mindfulness techniques have been particularly helpful in distressed populations with medium to large effects for distress reduction [9
Yet, it must also be kept in mind that persons with high levels of distress might be attracted by such trainings and thus expectations regarding the programme might account for some of the reduction in the distress score [49
]. This pattern would also be expected for mindfulness outcome; on the other hand, participants with high distress levels did not increase their level of mindfulness in a different way than participants with lower levels of distress. Although mindfulness has been previously reported to mediate positive effects on psychological well-being [50
] and perceived stress reduction [51
], data in this study did not show these mediating effects, but there were some associations between the measures. Hence, we cautiously assume that reduction effects in maladaptive psychological parameters are related to positive changes in mindfulness. Furthermore we found expected correlations, and—if not significant—trends, between mindfulness (FMI) and the other measures. These correlations have also been reported in other studies [29
In general, when analysing measures for real change as defined by Jacobson and Truax [39
] we found that persons in the treatment condition were 9 times as likely to report a positive change in PSQ than participants in the control group. With the other measures we were not able to detect significant differences between the groups.
One of the purposes of the training was that persons would learn mindfulness techniques in a structured way to use them "offline" when the web-based training finished. This assumption was supported by small to medium effects for PSQ, d = -0.35, FMI, d = 0.32, and PANASpos d = 0.43, from post-test to follow-up.
Programme acceptance and satisfaction was high for this web-based training. Despite findings that self-guided web-based trainings and interventions seem to yield smaller effects than programmes in which therapists or instructors are included [22
] this programme showed large effects on perceived stress for persons who regularly engaged in the training.
Although it is reported that attrition rates are a problem in web-based interventions [22
] this was not the case for the treatment group between pre- and post-test. On the other hand, drop-out rates for the waiting-list group during training were far higher than in the treatment group, suggesting that the delay of training might have caused higher attrition rates in this group. This was contrary to findings of other studies incorporating a mindfulness component [19
With the exercise introduced in module 2 a new form of interactive mindfulness exercise was tested. The exercise was inspired by Linehan's [33
] cloud exercise, in which persons imagine to place distressing sensations or thoughts on a cloud, watching it passing by. It was taken care that this did not act as vigilance task paradigm [55
], but as a support for the mindfulness aspect of letting go [56
]. It was expected that this kind of affect labelling would mitigate emotional distress by supporting affect labelling in a non-judgmental manner. There were medium, but non-significant associations between a greater reduction of PANASneg
and GSI with the use of the cloud technique in 3MFU. Also, when participants stated that they felt more aware of themselves and their emotions since they participated in the training, this was significantly associated with changes in PANASneg
. This is also supported by recent neurobiological studies on reduced amygdala response to emotional cues after affect labelling [57
] also indicating that this mechanism is related to mindfulness exercise [58
]. As the exercise was designed without spoken guidance, participants reported this to be more difficult.
The conclusions drawn from the results are limited by the heterogeneity of the data and also by group-differences in baseline measures with small to medium effect sizes. Graphical analysis of the data suggested, that this heterogeneity and baseline differences might have led to significance of some main time effects and non-significance of interaction effects in the analyses. A source of bias might also have been the recruitment of participants with different levels of initial distress, which could be responsible that interaction effects in GSI and FMI did not show significance. Another limitation was a missing control group in 3MFU, which should be addressed when conducting a larger scale study. Also the randomization procedure, using single-case randomization resulting in unequal sample sizes posed another limitation together with the limited power due to the small sample size.
Further limitations to generalizability are the high proportion of female participants, the high proportion of persons with academic background and the reliance on self-report. Especially education has been found to have a mediating influence on several aspects of mindfulness [50
]. There has also been the claim, that mindfulness should be measured with other means but self-report measures for better validity [29
]. As with most exercises and interventions offered online, it was not possible to control whether participants stayed in front of the screen and performed the exercises or did something different and simply returned after twenty minutes to log out. This however, will remain a problem with most web-based interventions [59