The overall aim of the current industrial PhD thesis was to evaluate the psychological effects of a series of web-based interventions (WBIs) developed on a proprietary information and communication technology (ICT) platform. First, the aim was to determine whether the WBIs had an effect on stress, mood, and depressive symptoms and subjective well-being (SWB) by means of randomized controlled trials. The second aim was to examine mediating and moderating mechanisms that play a role for the efficacy of these interventions while the third aim was to investigate how participant’s perceptions of an intervention affect its continued use.
The main findings in Paper I indicated that a mindfulness-based stress reduction intervention altered the normative development in stress levels over a period of six months, in a normal population. Participants in the control group did not show any significant changes in stress while participants in the intervention group reported a significant recovery from stress that was maintained at six months, despite experiencing increases in stress during the study period. Hence, participants receiving the stress intervention learned effective ways of managing their stress that they seemed to apply effectively when their levels of stress increased. Moreover, effective management of stress was attributed to increases in mindfulness and decreases in procrastination, and the intervention seemed to work equally well regardless of participants’ gender, age, and education.
The main findings in Paper II suggested that a positive psychology intervention altered the normative development in mood over the study period of six months in a normal population. As in the study on stress, participants in the control condition did not experience any significant changes in mood while participants in the treatment condition reported significant increases in mood over time. Changes in mood were irrespective of participants’ gender, age, and education, and could be accounted for by increases in optimism.
The main findings in Paper III demonstrated no main effect on depressive symptoms in a group of patients with human immunodeficiency virus (HIV), but some support of the intervention for SWB. There were no formal differences between the intervention and control group, however, improvements in SWB were exclusively found within the intervention group. The results indicated that more time had passed since participants who benefited from the intervention had their HIV diagnosis and started on medical treatment. In contrast, no such results were found for time since diagnosis or start on medical treatment in the control group.
The main findings in Paper IV were that an intervention for weight loss and eating habits and its’ design was perceived as persuasive which, in turn, was related to continued use of the intervention. Overall, male and female perceptions of the intervention were favourable; however, there were indications that males and females perceived the intervention and its’ design slightly different. Further research is needed to clarify and formally examine gender differences.
In summary, this thesis has demonstrated the efficacy of WBIs designed on a proprietary ICT platform which has the capacity for a high reach and implementation at a large scale in the public. Paper I and II shows that fully automated WBIs are sufficient to produce changes in stress and mood among normal and healthy people. Paper III suggests that such interventions may add value to patients living with HIV, but methodological weaknesses in the study prevented any final conclusions. Paper IV demonstrated that the design of the interventions is perceived favourably and should be pursued further. Moreover, the studies have documented the efficacy of rather novel approaches to WBIs and add to the scarce literature of WBIs on stress, positive psychology, subjective well-being, patients already diagnosed with HIV, and how WBIs are perceived among consumers.