Background Loneliness, or perceived social isolation, is prevalent in both the general population and clinical practice. Although loneliness has repeatedly been associated with mental and physical health, research on interventions that reduce loneliness effectively is still rather scarce. Objective This study aims to evaluate the efficacy of a guided and an unguided version of the same internet-based cognitive behavioral self-help program for loneliness (SOLUS-D) for adults. Methods A total of 250 participants will be randomly assigned to 1 of 2 intervention groups (SOLUS-D with guidance or SOLUS-D without guidance) or a wait-list control group (2:2:1 allocation ratio). Adult participants experiencing high levels of loneliness will be recruited from the general population. Individuals currently experiencing at least moderately severe depressive symptoms, an ongoing severe substance use disorder, previous or current bipolar or psychotic disorder, or acute suicidality will be excluded from the trial. Assessments will take place at baseline, 5 weeks (midassessment), and 10 weeks (postassessment). The primary outcome is loneliness assessed using the 9-item University of California, Los Angeles Loneliness Scale at the posttreatment time point. Secondary outcomes include depressive symptoms, symptoms of social anxiety, satisfaction with life, social network size, and variables assessing cognitive bias and social behavior. The maintenance of potentially achieved gains will be assessed and compared at 6 and 12 months after randomization in the 2 active conditions. Potential moderators and mediators will be tested exploratorily. Data will be analyzed on an intention-to-treat basis. Results Recruitment and data collection started in May 2021 and are expected to be completed by 2022, with the 12-month follow-up to be completed by 2023. As of the time of submission of the manuscript, 134 participants were randomized. Conclusions This 3-arm randomized controlled trial will add to the existing research on the efficacy of loneliness interventions. Furthermore, it will shed light on the role of human guidance in internet-based treatments for individuals with increased levels of loneliness and the possible mechanisms of change. If SOLUS-D proves effective, it could provide a low-threshold, cost-efficient method of helping and supporting individuals with increased levels of loneliness. Trial Registration ClinicalTrials.gov NCT04655196; https://clinicaltrials.gov/ct2/show/NCT04655196 International Registered Report Identifier (IRRID) DERR1-10.2196/36358

Einsamkeit kann situativ und vorübergehend sein, aber auch langanhaltend und überdauernd. Obwohl Einsamkeitsgefühle oft zusammen mit depressiven Störungen auftreten, sollten sie nicht ausschließlich als ein Symptom einer Depression verstanden werden. Dieser Beitrag befasst sich mit der Definition von Einsamkeit und einem Erklärungsmodell von chronischer Einsamkeit. Abschließend wird auf Interventionen zur Reduktion von Einsamkeit eingegangen.

BACKGROUND Loneliness, or perceived social isolation, is prevalent in both the general population and clinical practice. Although loneliness has repeatedly been associated with mental and physical health, research on interventions that reduce loneliness effectively is still rather scarce. OBJECTIVE This study aims to evaluate the efficacy of a guided and an unguided version of the same internet-based cognitive behavioral self-help program for loneliness (SOLUS-D) for adults. METHODS A total of 250 participants will be randomly assigned to either of two intervention groups (SOLUS-D with guidance or SOLUS-D without guidance) or a waitlist control group (2:2:1 allocation ratio). Adult participants suffering from high levels of loneliness will be recruited from the general population. Individuals with current severe depression or ongoing severe substance use disorder, previous or current bipolar or psychotic disorder, or acute suicidality will be excluded from the trial. Assessments take place at baseline, 5 (mid-treatment) and 10 weeks (post-treatment). The primary outcome is loneliness assessed with the 9-item UCLA Loneliness Scale at post-treatment. Secondary outcomes include depressive symptoms, symptoms of social anxiety, satisfaction with life, social network size, and variables assessing cognitive bias and social behavior. The maintenance of potentially achieved gains will be assessed and compared at 6 and 12 months after randomization in the two active conditions. Potential moderators and mediators will be tested exploratorily. Data will be analyzed on an intention-to-treat basis. RESULTS Recruitment and data collection started in May 2021 and is expected to be completed by 2022, with the 12-month follow-ups to be completed by 2023. As of the submission of the manuscript, 134 participants are randomized. CONCLUSIONS This three-arm randomized controlled trial will add to existing research on the efficacy of loneliness interventions. Furthermore, it will shed light on the role of human guidance in internet-based treatments for lonely individuals and possible mechanisms of change. If SOLUS-D proves effective, it could provide a low-threshold, cost-efficient way to help and support lonely individuals. CLINICALTRIAL The trial was registered on December 7, 2020, at ClinicalTrials.gov NCT04655196; https://clinicaltrials.gov/ct2/show/NCT04655196. In case of important protocol modifications, trial registration will be updated.

Chronische Einsamkeit geht mit einer Reihe negativer Konsequenzen für die psychische und physische Gesundheit einher. Da chronische Einsamkeit oft mit Schamgefühlen zusammenhängt, bedarf es niederschwelliger Interventionen, um Betroffene zu unterstützen. Nach einer Einleitung zu Internet-basierten Selbsthilfeinterventionen wird das Selbsthilfeprogramm SOLUS-D vorgestellt, das zur Reduktion von chronischer Einsamkeit konzipiert wurde.

Loneliness is a prevalent and stigmatized phenomenon associated with adverse (mental) health outcomes. However, evidence-based interventions to alleviate loneliness are scarce. This randomized controlled trial (ClinicalTrials.gov-ID: NCT04655196) evaluated the efficacy of an internet-based cognitive behavioral self-help intervention (ICBT) to reduce loneliness by comparing two intervention groups with guidance or automated messages against a waitlist control group. Adults (N = 243) suffering from loneliness were recruited from the general public and then randomly assigned (2:2:1) to a 10-week ICBT with human guidance (GU) or automated messages (AM) or to a waitlist control group (WL). Loneliness, assessed with the UCLA-9, was the primary outcome. Outcomes were assessed at baseline and 10 weeks (post) and analyzed using mixed-effects models. The pooled intervention conditions resulted in lower loneliness scores at post-assessment than the WL (Cohen’s d = 0.57, 95%-CI [0.25; 0.89]) and reduced depressive symptoms, social anxiety, social avoidance behavior, and rejection sensitivity (d = 0.32–0.52). The GU group had lower loneliness scores at post-assessment than the AM group (d = 0.42, 95%-CI [0.13; 0.70]). ICBT effectively alleviated loneliness, and guidance increased the reduction in loneliness compared to automated messages. Alleviating loneliness with ICBT further seems to reduce the overall burden of psychopathological symptoms.