Group-Based Positive Affect Intervention for Loneliness Reduction: A Randomized Controlled Trial in Chinese Young Adults

Loneliness among young adults has become a growing public health concern, linked to depression, anxiety, low self-esteem, and reduced life satisfaction. Unlike older adults, whose loneliness is often tied to social isolation, loneliness in young adulthood is shaped by developmental transitions, shifting relational needs, and heightened sensitivity to social evaluation. Existing interventions largely target older populations and often fail to address the emotional and cognitive processes central to loneliness in younger groups.

This study addresses these gaps by adopting a multi-theoretical framework that integrates the Social Needs Perspective, Weiss's Multidimensional Theory, the Cognitive Discrepancy Model, and the Reaffiliation Motive Model. Together, these perspectives conceptualize loneliness as arising from unmet needs for meaningful connection, discrepancies between desired and actual relationships, and maladaptive cognitive and behavioral responses that hinder reconnection.

The study employs a two-arm randomized controlled trial design. A total of 100 college students in Hong Kong and mainland China who report elevated loneliness will be recruited and screened using the UCLA Loneliness Scale. Eligible participants will be randomly assigned to either the group-based Positive Affect (PA) intervention or the group-based Social Skills Training (SST) active control condition. Both interventions will be delivered in four weekly group sessions lasting 45-60 minutes.

• The PA Intervention: Grounded in the Broaden-and-Build Theory and revised Stress and Coping Theory. It adopts a multi-skill approach to enhance positive emotions through practices such as savoring positive events, gratitude, mindfulness, positive reappraisal, strengths identification, goal setting, and acts of kindness. These skills are expected to increase positive affect, promote social engagement, and strengthen psychological resources, thereby reducing loneliness.
• The SST Intervention: Serves as an active control and focuses on improving interpersonal competence. It includes training in social behavior styles (assertive, shy, and aggressive), initiating and maintaining social interactions, setting boundaries, giving and receiving feedback, and conflict resolution. Improvements in interpersonal competence are expected to enhance perceived social support, which in turn reduces loneliness.

Primary outcomes will be assessed using the UCLA Loneliness Scale, with additional measures capturing positive affect, perceived social support, social network discrepancy, mindfulness, emotion regulation, self-efficacy, and rejection sensitivity. Data will be collected at baseline, with follow-ups at 1 and 3 months. Linear mixed-effects models will be used to examine intervention effects over time, while mediation and moderated mediation analyses will test the proposed mechanisms.