The Feasibility, Acceptability and Preliminary Efficacy of a Group Intervention to Reduce Loneliness

Severe loneliness is a large and growing clinical and societal problem. Although there are interventions for loneliness, elevated levels often remain. This pilot study evaluates the feasibility and acceptability of an intervention to alleviate social and emotional loneliness among students. The second aim is to obtain effect sizes that inform sample size calculations of a subsequent randomized controlled trial (RCT). The goal of this clinical trial is to learn about the feasibility and acceptability of a group intervention aimed at reducing social and emotional loneliness and social isolation in students. In addition, we want to obtain effect sizes that can inform the sample size calculation of a subsequent randomized controlled trial (RCT).

The hypotheses are that:

* Participants after completing the intervention have reduced levels of social and emotional loneliness and social isolation compared to baseline (primary outcomes).
* Participants after completing the intervention have reduced levels of social anxiety, depressive symptoms, and better daily functioning compared to baseline (secondary outcomes).

Before the group intervention starts, participants will first follow a baseline period, ranging between 1 and 7 weeks. The length of the baseline period is based on the date of enrolment and therefore not random. Following the baseline period, all participants will start in the group intervention. This intervention aims to encourage social behavioural activation tailored to the values of the participant and teach skills that make negative emotions and thoughts less bothersome and reduce feelings of loneliness. This intervention consists of seven weekly group sessions and a booster session. The intervention is offered in a group format to maximize possibilities for interpersonal therapeutic practice and is framed as a psycho-educational course to increase its acceptability.

Data are collected at screening, pre-intervention, post-intervention, one-month follow-up and three-month follow-up, as well as during weekly measurements during the baseline period and the course period. Primary outcome measures are social and emotional loneliness and social isolation. Secondary outcome measures are social anxiety, depression, and daily functioning. Other outcome measures are interpersonal problems and assessment of the sessions.

Participants will be recruited via posters at the University of Amsterdam.


Eligibility Criteria:
Inclusion criteria:

* Being at least 16 years old
* Exhibiting at least moderate levels of loneliness as assessed by the De Jong Gierveld Loneliness Scale 11-item version (DJGLS; de Jong-Gierveld \& Kamphuls, 1985)
* Possessing sufficient proficiency in the English language.

Exclusion criteria:

- The presence of severe (psychiatric) problems that hinder participation in the study or require other forms of immediate care, as indicated by the Mini International Neuropsychiatric Interview 7.0.2 (MINI; Sheehan et al., 1998).

If participants were already receiving psychological or pharmacological treatment for psychiatric problems, this treatment had to be temporarily interrupted for the duration of the study in consultation with the participant's clinician.