A Meaning-centered Intervention for Individuals Who Tend to Feel Down or Anxious
Phase: NA
Conditions: Depressive and/or Anxiety Symptoms
Sponsor: University of Groningen

19.6.25 
Study Protocol 
Meaning-centered Intervention (PSY-2324-S-0451) 
Procedure 
Recruitment will take place through the student-participant pool of the Faculty of 
Behavioral and Social Sciences at the University of Groningen. Participants for the trial are 
selected based on an online screening study. After reading the study information and giving 
consent, participants are screened on i) treatment status (“Are you currently in treatment for a 
depressive or anxiety disorder?”) ii) suicidality (item 9 of the BDI-II; Beck et al. 1996), and iii) 
depressive and anxiety symptoms per PHQ-4 (Kroenke et al., 2009; Löwe et al., 2014). 
Participants who display a total score of ≥ 2 on the PHQ-4, who are not in treatment, and do not 
indicate suicidality were eligible for the trial. 
Upon meeting the eligibility criteria, participants were invited to participate in the 
meaning-centered intervention trial via an email which explains the most important information 
of the study (e.g. design, content of the meaning-intervention, compensation) and includes a link 
to the online environment of the baseline assessment. After reading the study information and 
giving consent, participants fill in demographics (age, gender, nationality, primary language) and 
their availability for the first intervention session. After that, they fill in a series of questionnaires 
that are presented in randomized order: 
• Meaning in Life Questionnaire (MLQ; Steger et al., 2006) 
• Three-dimensional Meaning Scale (3DM; Martela & Steger, 2023) 
• Balanced Measure of Psychological Needs (BMPN; Sheldon & Hilpert, 2012) 
• Self-control: Brief Self-control Scale (BSCS; Tangney, Baumeister, & Boone, 
2004) 
• Intolerance of Uncertainty scale (Carlton et al., 2007) 
• A Short Boredom Proneness Scale (Struk et al., 2017) 
• Depression, Anxiety and Stress Scales–21(DASS-21; Lovibond, 1995) 
• Short form of social interaction anxiety scale and social phobia scale (SIAS-6, 
SPS-6; Peters et al., 2012) 
• Loneliness Scale (de Jong-Gierveld & van Tilburg, 1999) 
• Robert UCLA Loneliness Scale (Goossens et al., 2014) 
• Rosenberg self-esteem scale (Rosenberg, 1979) 
• Drinking: Alcohol Use Disorders Identification Test (AUDIT; Saunders, Aasland, 
Babor, de la Fuente, & Grant, 1993) 
• “Govern” subscale of the Temptation and Restraint Inventory (Collins & Lapp, 
1992) 
• Drinking Motive Questionnaire (Cooper, 1994) 
• Drinking Pattern Behaviour (Kurihara et al., 2022) 
 
Then, participants are asked if they were familiar with the names of any intervention 
trainer involved in the study. Finally, they are thanked for their participation and informed about 
the next steps. After completing the baseline assessment, they are randomly assigned to either the 
waitlist or the intervention condition by simple randomization using a true random number 

generator (random.org). Participants in the intervention condition are contacted by a trainer that 
would then conduct the intervention session with them in either Dutch, English, or German. 
Participants in the intervention condition followed six 1-hour online sessions of a meaning-
centered intervention for internalizing symptoms (for details on the original intervention 
designed for eating disorders, see van Doornik et al., 2024), with sessions taking place 
approximately every 4 days. Immediately after completion of the last intervention session, 
participants in the intervention condition will receive the link to the post-assessment 
questionnaire. Participants in the waitlist condition will be informed that they are assigned to the 
waitlist condition and that in a month from now they will receive the link to the post-assessment. 
Waitlist participants will be also informed that they can follow the intervention themselves once 
data collection completes, prospectively in June 2026. One month after the post-assessment, both 
conditions will be asked to complete the follow-up assessment. For all assessments, participants 
will be compensated with SONA credits. 
 
Statistical Analyses 
All analyses will be run in R. All analyses will be run as completer analysis, given our aim to 
assess the efficacy of the present intervention in a subclinical sample (Silverman et al., 2024). 
Missing values will be imputed using predictive mean matching. Analyses will be run with and 
without influential observations (i.e., observations showing high standardized residuals and/or 
leverage). Differences in outcomes between analyses with and without influential points will be 
reported. 
 
A minimal sample size of N =128 is required to yield power of 0.8 based on testing a one-way 
ANCOVA with α-level of .05, effect size of f = 0.25, number of groups = 2, max. number of 
covariates = 2, and numerator df = 1. We aimed to recruit 142 participants, assuming a drop-out 
rate of 10%. 
 
Primary Outcomes: Meaning in life and Internalizing Symptoms 
 
H1a: The meaning-centered intervention increases meaning in life at post assessment and follow-
up, compared to a waitlist control. 
 
H1b: The meaning-centered intervention reduces internalizing symptoms at post assessment and 
follow-up, compared to a waitlist control. 
 
The effect of the intervention on both meaning and internalizing symptoms will be tested by 
running a MANCOVA with post-assessment sum score of presence subscale of the MLQ and 
DASS-21 sum score as dependent variables, with baseline presence sum score and baseline 
DASS-21 sum score as covariate and condition (intervention, waitlist) as the between-subjects 
factor. This step will be repeated with the follow-up scores as dependent variables and baseline 
and post-assessment score as covariates. All resulting p values will be tested against an alpha 
level of 0.05. 
 
The effect of the intervention specifically on either primary outcome will be tested using 
ANCOVAs. The first ANCOVA will test the effect on meaning in life, with post-assessment sum 
score of presence subscale of the MLQ as dependent variable and baseline presence sum score as 

covariate, with condition (intervention, waitlist) as a between-subjects factor. This step will be 
repeated with the follow-up scores as dependent variable and baseline and post-assessment score 
as covariates. 
The effect of the intervention on internalizing symptoms will be tested by an ANCOVA with 
post-assessment DASS-21 sum score as dependent variable and baseline DASS-21 sum score as 
covariate, with condition (intervention, waitlist) as a between-subjects factor. This step will be 
repeated with the follow-up scores as dependent variable and baseline and post-assessment score 
as covariates. 
 
Secondary Outcomes: Dyscontrolled Drinking and Three-Dimensional Meaning 
 
H2a: The meaning-centered intervention reduces dyscontrolled drinking at post assessment and 
follow-up, compared to a waitlist control. 
 
H2a: The meaning-centered intervention increases coherence, purpose, and significance at post 
assessment and follow-up, compared to a waitlist control. 
 
The effect of the intervention on the secondary outcomes dyscontrolled drinking and three-
dimensional meaning will be tested using ANCOVAs. The effect on dyscontrolled drinking will 
be tested using post-assessment sum score of the Govern subscale of the Temptation and 
Restraint Inventory as dependent variable and baseline Govern sum score as covariate, with 
condition (intervention, waitlist) as a between-subjects factor. This step will be repeated with the 
follow-up scores as dependent variable and baseline and post-assessment score as covariates. 
The effect on three-dimensional meaning will be tested with three ANCOVAs with post-
assessment coherence, purpose, and significance sum score as dependent variable and their 
baseline scores as covariate, with condition (intervention, waitlist) as a between-subjects factor. 
This step will be repeated with the follow-up scores as dependent variable and baseline and post-
assessment score as covariates. The alpha level for the p values resulting from the ANCOVAs 
for the secondary outcomes will be adjusted by Bonferroni-Holm multiple testing correction. 
 
Secondary Analysis: Invariant Causal Prediction 
We will analyze the causal relationships between all assessed variables via the Invariant causal 
prediction (ICP) algorithm (Meinshausen et al., 2016) using code adapted from Kossakowski et 
al. (2021). The ICP infers causal relationships by testing the residual distribution of a target 
variable given all possible subsets of predictors against the residual distribution of that variable 
in the other condition (i.e., intervention or waitlist), using a Kolmogorov-Smirnov test. This 
procedure is followed for every variable as target variable. Predictors of the target variable which 
are part of each invariant subset are implied as causes. A subsampling procedure tests which of 
those relationships hold across random subsamples of participants. We will run the ICP on the 
post-change scores of all variables. We will also run the ICP on the follow-up-baseline change 
scores of all variables. Missing data will be imputed using predictive mean matching imputation 
in the "mice" package (van Buuren & Groothuis-Oudshoorn, 2011). The ICP corrects for 
familywise error rates using Bonferroni. The ICP will be used for exploratory analysis and 
inspected for the hypothesized relationships for primary and secondary outcomes described 
above as well as for the causal link between meaning and internalizing symptoms through 
intolerance of uncertainty (Ostafin et al., 2022). 

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https://doi.org/10.1016/j.beth.2023.05.012 
 
 

INFORMED CONSENT 
 
 
“Meaning-centered Intervention” 
PSY-2324-S-0451 
 
● I have read the information about the research. I have had enough opportunity to 
ask questions about it. 
 
● I understand what the research is about, what is being asked of me, which 
consequences participation can have, how my data will be handled, and what my 
rights as a participant are.  
 
● I understand that participation in the research is voluntary. I myself choose to 
participate. I can stop participating at any moment. If I stop, I do not need to 
explain why. Stopping will have no negative consequences for me. 
 
● Below I indicate what I am consenting to. 
 
Consent to participate in the research: 
[ ] Yes, I consent to participate; this consent is valid until 30-06-2026 
[ ] No, I do not consent to participate 
 
Consent to processing my personal data:  
[ ] Yes, I consent to the processing of my personal data as mentioned in the research 
information (i.e. SONA ID, e-mail address). I know that until one month after 
participation I can ask to have my data withdrawn and erased. I can also ask for this if I 
decide to stop participating in the research. 
[ ] No, I do not consent to the processing of my personal data.