About this trial

Considering the high prevalence of couple distress in Western countries and rising divorce rates, there is a pressing need for accessible and evidence-supported interventions that can strengthen relationship functioning. Although mindfulness has been positively linked to relationship functioning, only few studies have investigated the effects of mindfulness interventions specifically targeted at couples. However, these studies suffer from methodological limitations such as lack of an active control group.

To address this gap, a feasibility trial with progression to a full-scale randomized controlled trial (RCT) will be conducted, depending on whether stoppage criteria are met, to evaluate the effectiveness of a Mindfulness-Based Couple Intervention (MBCI) compared to an online active control intervention (Self-expansion Intervention) and waitlist control group. Moreover, consolidation of intervention effects is examined up to 6 months post-intervention. Finally, possible working mechanisms and the effect of potential moderators are examined.

The current study has three arms: (i) MBCI, (ii) active control intervention (i.e., a self-expansion program) and (iii) waitlist control, with assessments at baseline (T0), immediately post-intervention (T1) and at 6 months post-intervention (T2). After the follow-up assessments, waitlisted participants are offered to take part in (an online version of) either the MBCI or the active control intervention.

The study aims to include 213 couples (426 participants, age \>20 years) with a minimum relationship duration of 2 years. Couples will be randomly assigned with a 3:3:2 ratio to MBCI, Self-expansion or waitlist, respectively (with a total of 80 couples in the intervention groups and 53 couples in the waitlist control group). This is a multi-site RCT, with five different centers spread across the Netherlands, based in Nijmegen, Tilburg, Amsterdam, Maastricht and Groningen. In the feasibility phase, 42 eligible couples will be recruited from two sites (Nijmegen and Tilburg). Stratified variable block randomization will be used(block sizes of 8 and 16), with study site as stratification factor.

The MBCI is a close adaptation of the widely used and well-researched Mindfulness-Based Stress Reduction program (MBSR), developed by our research team. Couples learn how to practice mindfulness meditation and how to apply mindfulness in their daily life and in their relationship. As compared to the MBSR, it includes adapted and additional exercises to practice mindfulness within the relationships, such as mindful communication exercises, mindful touch, and mindfully viewing one's partner. The active control intervention encourages couples to invest in self-expansion, by doing a novel activity together every week. This intervention is based on self-expansion theory. According to this theory, couples are satisfied with their relationship as long as they experience a sense of self-expansion. A sense of self-expansion can be promoted by engaging in novel activities together and gaining new insights from each other. Both the mindfulness- and self-expansion interventions consist of 8 weekly sessions, plus a silent day (for MBCI) or a day out (for the self-expansion intervention). Interventions are similar in non-specific factors such as format, structure, time commitment, teacher support, and group dynamics.

The primary outcome is to compare self-reported relationship satisfaction as measured by the Couple Satisfaction Index (CSI-4) from pre-intervention (T0) to immediately post-intervention (T1) between the MBCI group compared to the active control group and between the MBCI group compared to the waitlist control group. Secondary outcomes include the difference in relationship satisfaction from pre-intervention (T0) to 6 month post-intervention (T2) between participants in the MBCI compared to the active and waitlist control group, as well as differences between participants in the MBCI compared to the active and waitlist control group in various relationship behaviors, perceptions of the partner, and individual outcomes measured from pre-intervention (T0) to immediately post-intervention (T1) and pre-intervention (T0) to 6 months post-intervention (T2). In addition, a number of potential moderators, including commitment, attachment style and trait mindfulness measured at T0 will be assessed to determine for whom these programs work.

Unless the trial team determines, based on stoppage criteria, that trial procedures need important modifications thereby re-setting the full-scale trial as a new trial, the outcome data of the participants in the feasibility portion will be utilized in the analyses of the full-scale trial.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

age >20 years

relationship duration of >2 years

Disqualifiers

One or both partners have followed an MBSR- or MBCT training or similar mindfulness program for at least four sessions in the past three years.

One or both partners are currently in relationship therapy.

One or both partners are unable to sufficiently speak and understand the Dutch language.

Presence of severe mental disorders in one or both partners, namely addiction, suicidality (in the past 12 months) or psychosis (in the past 12 months?).

Trial design

Design model

Parallel

Treatments tested in this trial

SE training
Behavioral
Self-expansion training
MBCI
Behavioral
Mindfulness-based Couple Intervention (MBCI)

Treatment groups

426 Participants

are divided into 3 treatment groups

Group A: Mindfulness-Based Couple InterventionExperimental treatment 1 intervention

Group B: Self-expansion trainingActive comparator 1 intervention

Group C: Waitlist controlNo intervention 0 interventions

Trial outcomes

Primary outcomes

1

Difference in Couple Satisfaction Index-4 scores between participants in the MBCI arm and waitlist control, between participants in the SE arm and waitlist control, and between participants in the MBCI arm and SE arm immediately post-intervention

The Couple Satisfaction Index (4 items, CSI-4) measures relationship satisfaction, a global assessment of contentment in the romantic relationship. The first item is measured on a 7-point Likert scale (0=extremely unhappy, 6=perfect), the other items on a 5-point Likert scale (0=not at all, 5=completely). Maximum score =22. Higher scores indicate higher satisfaction.

Time frame

Time Frame: 1 week post-intervention

Secondary outcomes

1

Difference in Couple Satisfaction Index-4 scores between participants in the MBCI arm and waitlist control, between participants in the SE arm and waitlist control, and between participants in the MBCI arm and SE arm immediately post-intervention

The Couple Satisfaction Index (4 items, CSI-4) measures relationship satisfaction, a global assessment of contentment in the romantic relationship. The first item is measured on a 7-point Likert scale (0=extremely unhappy, 6=perfect), the other items on a 5-point Likert scale (0=not at all, 5=completely). Maximum score =22. Higher scores indicate higher satisfaction.

Time frame

6 months post-intervention

2

Relationship distress: Multidimension Stress Questionnaire for couples (MSF-P)

Relationship distress indicates subjective strain in the relationship because of stressors arising within the relationship. It is measured by the Multidimension Stress Questionnaire for couples (MSF-P) internal stress dimension, which consists of 10 items scored on a 4 point Likert scale (1=not at all, 4= strong). Higher scores indicate higher relationship distress. Maximum score = 40.

Time frame

1 week post-intervention and 6 months post-intervention

3

Emotional intimacy: Perceived Relationship Quality Component scale (PRQC)

Emotional intimacy involves the perceived closeness, sharing of feelings, and emotional bonding with the partner. It is measured by the intimacy dimension of the Perceived Relationship Quality Component scale (PRQC) and consists of 3 items measured on a 7 point Likert scale (1 = not at all; 7 = extremely). Higher scores indicate higher emotional intimacy. Maximum score = 21.

Time frame

1 week post-intervention and 6 months post-intervention

4

Perceived Partner Responsiveness: Perceived Responsiveness and Insensitivity scale (PRI)

Perceived partner responsiveness is the perception that the partner understands, validates, and cares about one's core needs during disclosure - reflecting attentiveness and emotional responsiveness. It is measured by the Perceived Responsiveness and Insensitivity scale (PRI), which consists of 8 items scored on a 6-point Likert scale (0= not at all; 5= completely). Maximum score = 40.

Time frame

1 week post-intervention and 6 months post-intervention

Other outcomes

1

Pre measurement commitment as a moderator of the effect of MBCI on change in relationship satisfaction from pre to post and pre to follow up compared to active and waitlist control groups.

Commitment is the intention to maintain a romantic relationship over the long term. It is measured by the commitment level items from the Investment Model Scale (IMS) and consists of 7 items rated on an 8-point Likert scale (1= do not agree at all; 8= agree completely). Higher scores indicate higher commitment. Maximum score = 56.

Time frame

Pre measurement in the month before start of the intervention.

2

Pre measurement attachment style as a moderator of the effect of MBCI on change in relationship satisfaction from pre to post and pre to follow up compared to active and waitlist control groups.

Attachment style is the characteristic way people relate to others in the context of intimate relationships, developed during childhood. Attachment style is typically measured on two dimensions: anxious (worry about partner's availability) and avoidant (discomfort with intimacy). It is measured by the Experiences in Close Relationships Scale short form revised (ECRS-sf) and consists of 12 items scored on a 7 point Likert scale (1 = strongly disagree, 7 = strongly agree). Higher scores indicate higher insecure attachment. 6 items assess attachment anxiety (maximum score=48) and 6 items assess attachment avoidance (maximum score = 48).

Time frame

Pre measurement in the month before start of the intervention.

3

Expectancy of the training

Expectancy of the training is measured with the Credibility Expectancy Questionnaire (CEQ). The CEQ is adapted to be specific to relationship improvement. This measure is only administered to participants who are randomized tot he intervention. It consists of 5 items rated on a 10 point Likert scale (1= not at all; 10 = very much). It consists of a credibility subscale (4 items, maximum score = 40) and an expectancy subscale (1 item, maximum score =10).

Time frame

After randomization, before start of the intervention.

4

Motivation

Motivation of taking part in the intervention is assessed with 2 items, one designed by our research team and one taken from Conradi et al. (2018). This measure is only administered to participants randomized to an intervention. Items are rated on a 5 point Likert scale (1= strongly disagree; 5= strongly agree). Higher scores indicate higher motivation. Maximum score = 10.

Time frame

After randomization, before start of the intervention

Mindfulness in Couples

About this trial

Eligibility criteria

Qualifiers

Disqualifiers

Trial design

Treatments tested in this trial

Treatment groups

Trial outcomes

Primary outcomes

Secondary outcomes

Other outcomes

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