Improving Happiness in Flanders

This randomized trial has two aims:

• First, it investigates the efficacy of two different happiness interventions in increasing feelings of happiness in the Flemish general population using a wait-list controlled design.
• Second, this study aims to identify predictors of response in both interventions ("what works for whom?")

Methods

Design and procedure

• Participants will be contacted through social media and directed to a website that is specifically designed for this study.
• All participants who register for the study first will electronically sign an informed consent and will be asked to complete a brief battery of questionnaires online (base line measures) before randomization.
• Participants then are assigned randomly using a block-randomized design to one of the three conditions using a computerized algorithm:

• a condition in which daily small and concrete happiness tips are sent to participants during one month via email (n=400)
• a condition in which weekly more in-depth happiness tips with a (doing and experiencing) task are given during one month via email (n=400)
• a wait-list condition (1 month); these participants will be subsequently (after the end of the 4-week intervention) randomized to condition (a) or (b) (n=400) using a block-randomized design.
• All participants will be assessed weekly during the intervention (see below) and followed-up 6 months after the end of the study.

Measures

Participants will complete a detailed demographic questionnaire.

Primary outcome measures:

• Subjective Happiness Scale (SHS; Lyubomirsky & Lepper, 1999)
• Steen Happiness Inventory (SHI; Seligman, Steen, Park, & Peterson, 2005)

Secondary outcome measures

• Positive and Negative Affect Scales (PANAS; Watson, Clark, & Tellegen, 1988)
• Patient Health Questionnaire-9 (PHQ-9; Kroenke, Spitzer, & Williams, 2001)
• Warwick Edinburgh Mental Well-Being Scale (WEMWBS; Tennant et al., 2007)
• Brief Symptom Inventory (Korte KlachtenLijst; KKL; Lange, & Appelo, 2007)

Predictors of outcome

• Meaning in Life Questionnaire (MLQ; Steger, Frazier, Oishi, & Kaler, 2006)
• Depressive Experiences Questionnaire (DEQ; Blatt, D'Afflitti, & Quinlan, 1976)
• Experiences in Close Relationships-Revised (ECR-R, Fraley, Waller, & Brennan, 2000)
• Kentucky Inventory of Mindfulness (KIMS; Baer, Smith, & Allen, 2004)
• Toronto Alexithymia Scale (TAS; Bagby, Parker, & Taylor, 1994)

Data analyses

Repeated measures Anova and multilevel modeling will be used to assess differences between the three conditions in primary and secondary outcomes at the end of the intervention and at follow-up. Regression analyses and growth curve modeling will be used to examine the effects of the predictors on primary and secondary outcomes.

Inclusion criteria

• Sufficient fluency in Flemish
• at least 18 years of age

Exclusion criteria

• no fluency in Flemish
• living outside of Flanders