The full intervention (FI) group received a psycho-education module about MD and its addictive behavior mechanism, a motivation enhancement module based on motivational interviewing, mindfulness modules, and self-monitoring modules.

The partial intervention (PI) group received an intervention identical to the FI group (a psycho-education module about MD and its addictive behavior mechanism, a motivation enhancement module based on motivational interviewing, mindfulness modules) with the exclusion of the self-monitoring modules.

Waiting List (WL) group did not undergo any intervention during the study period. However, WL participants were told that the program will commence in three months. During their waiting time participants were instructed to reduce their daydreaming activity to the best of their ability. Since all participants were recruited for this study from an online support forum (that is not part of this research design), the investigators labeled WL as the Internet Support as Usual (ISAU) group.

An 8-weeks internet-based self-guided intervention program, accompanied by e-mail. The content of the intervention and training modules comprised texts, illustrations, explanatory video and audio lectures, as well as interactive worksheets embedded in each week's lesson. Typically, a lesson started with a textual description of its target and duration. Then, participants received a summary of what had been taught thus far, and finally, a novel technique or skill was introduced. Each lesson required about 60 minutes to complete. Users had open access to web pages of previous lessons. Upon completion of each lesson, participants received a list of home assignments to practice during the following week. Our internet-based program featured a notification and download center containing the program's materials and pertinent messages from the researchers.

Change in the 16-item Maladaptive Daydreaming Scale (MDS-16) compared to baseline, measured 2 months and 6 months post-intervention. The MDS-16 is the primary self-report scale that gauges maladaptive daydreaming on a 10-point Likert scale. Scores range from 0 to 100, with the mean score of 40 set as an evidence-based cut-off score for clinical-level MD. Higher scores indicate an elevated level of maladaptive daydreaming, hence, a worse outcome.

Change in the Daydreaming Frequency Scale (DDFS) compared to baseline, measured 2 months and 6 months post-intervention. The DDFS is a 12-item subscale of the Imaginal Processes Inventory, gauging reported daydreaming frequency. Items are marked on a 5-point Likert scale. Scores range from 12 to 60. Higher scores indicate an elevated frequency of daydreaming, hence, a worse outcome.

Change in the Daydreaming Work and Social Adjustment Scale (DWSAS) compared to baseline, measured 2 months and 6 months post-intervention. The DWSAS is a 6-item measure assessing adjustment and disfunction in relation to daydreaming. Items are ranked on a 9-point Likert scale ranging from 0 to 8. The DWSAS scores range from 0 to 48. A score of 12 or lower indicates "no pathology and disfunction". Scores between 12 and 24 indicate "pathology and impaired function", while scores of 24 or above suggest "severe pathology and impaired function".

Change in the Brief Symptom Inventory (BSI) compared to baseline, measured 2 months and 6 months post-intervention. The BSI is a 53-item scale rated on a 5-point Likert scale of general psychopathology. The BSI is divided into nine subscales: somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, psychoticism, and four additional items. The BSI total score ranges from 0 to 4. Higher scores suggest elevated psychopathology, hence, a worse outcome.

Change in the Mindful Attention Awareness Scale (MAAS) from baseline, measured 2 months and 6 months post-intervention. The MAAS assesses awareness and mindful attention and is a common measure in psychological studies of mindfulness training. It gauges the extent to which participants acquired the target mindfulness skill. This is a 15-item, 6-point Likert scale with scores ranging from 15 to 90. Higher scores suggest a higher level of acquired the target mindfulness skills, hence, a better outcome.