Social disconnection is a significant problem in anxiety and depressive disorders, often failing to respond adequately to existing treatments. This lack of response highlights the need for novel therapeutic approaches. The positive valence system, crucial for social bond formation and maintenance, frequently shows hyporesponsivity in individuals with anxiety or depression. This hyporesponsivity manifests as low positive affect, diminished approach motivation, and reduced mesolimbic circuit activation during reward processing, particularly concerning social rewards. This diminished social reward sensitivity is strongly associated with social connectedness, independent of negative valence processes. Therefore, enhancing social reward sensitivity presents a potential transdiagnostic target for improving social connection. First-line treatments often fall short in addressing these positive valence deficits, explaining the persistence of social impairment even after established treatment. Amplification of Positivity (AMP), a cognitive-behavioral intervention, aims to address this gap by targeting positive valence thoughts, behaviors, and emotions through techniques like savoring, gratitude, and acts of kindness. Preliminary evidence suggests AMP increases positive affect and social connectedness. This study, aligned with the National Institute of Mental Health experimental therapeutics pipeline, aims to determine if AMP enhances social reward sensitivity, a key mechanism thought to underlie social connectedness.

Extensive research demonstrates a strong link between social disconnection and impairment in anxiety and depressive disorders. Current treatments often fail to adequately address the social deficits experienced by these individuals. The positive valence system, encompassing brain regions like the striatum and its associated circuitry, is central to social reward processing and social connection. Hyporesponsivity within this system, characterized by reduced positive affect, motivation, and neural activation during reward anticipation, is a common feature of anxiety and depression, contributing to social anhedonia and impairment. The striatum's role in anticipating social rewards, such as viewing a smiling face or engaging in self-disclosure, underscores its importance in social connection. Existing treatments typically do not effectively address these positive valence deficits, leaving social impairments unresolved. Amplification of Positivity (AMP), a novel intervention, directly targets positive valence processes through cognitive and behavioral strategies. Unlike standard treatments, AMP incorporates techniques designed to increase exposure and responsiveness to positive events, cultivate gratitude, and encourage acts of kindness. Previous studies in nonclinical populations and in those seeking treatment for anxiety and depression demonstrated AMP's effectiveness in boosting positive affect and social connectedness.

This 3-arm, parallel randomized controlled trial evaluated two doses of AMP (5 or 10 sessions) against a waitlist control in 68 adults with clinically elevated anxiety and/or depression and moderate social impairment. The primary outcome measured changes in striatal activation during social reward anticipation using fMRI, focusing on the contrast between social reward anticipation and neutral outcomes. Secondary outcomes, assessed via a social affiliation task, included positive affect, facial expressions, approach behavior, future interaction motivation, and respiratory sinus arrhythmia reactivity. Exploratory outcomes comprised measures of social connectedness (NIH Toolbox Friendship and Loneliness surveys, Social Connectedness Scale Revised), social functioning, symptoms, and well-being. AMP, a manualized clinician-delivered intervention, consisted of three core elements: increasing responsiveness to positive events; practicing gratitude; and engaging in acts of kindness. The 10-session AMP included additional activities building upon the core domains. A social incentive delay task (SID) was employed to assess social reward anticipation, while a social affiliation task provided secondary measures. Participants provided informed consent and underwent baseline assessments before randomization. Post-assessments occurred after treatment completion or the equivalent waitlist period. Statistical analyses used linear mixed-effects models for fMRI data and other measures, with Cohen's d calculated for effect size computations. Intent-to-treat analysis included all participants with baseline data and at least one post-baseline measurement.

The study found that AMP significantly increased striatal activation during social reward anticipation compared to the waitlist (large effect size, d = 1.01). This effect was observed across multiple striatal regions, including the nucleus accumbens, caudate, and putamen. AMP also yielded larger improvements in post-conversation positive affect (d = 0.62) and social approach behaviors (d = 0.65) compared to the waitlist. However, no significant group differences were observed for respiratory sinus arrhythmia reactivity, positive facial expressions, or future approach motivation. The 5-session AMP regimen showed nominally larger increases in striatal activation and social connectedness compared to the 10-session version. Exploratory analyses revealed significant AMP-related improvements in social connectedness, anxiety, depression, positive and negative affect, functional interference, and psychological well-being, compared to the waitlist (large effect sizes).

This study provides initial evidence supporting AMP's effectiveness in enhancing social reward responsivity in individuals with anxiety or depression. The observed increase in striatal activation during social reward anticipation suggests AMP engages a crucial mechanism underlying the motivation to connect with others. This is, to the authors' knowledge, the first demonstration of a psychosocial treatment enhancing striatal activity during social reward processing in these populations. The findings suggest that AMP may provide a novel approach for remediating social disconnection in these disorders. The finding that the shorter, 5-session AMP yielded larger increases in striatal activation and social connectedness compared to the 10-session version suggests that a more concise intervention may be equally or even more effective. This emphasizes the importance of optimizing treatment dosage and duration to maximize clinical impact. Although not powered for clinical efficacy, exploratory analyses demonstrated substantial improvements in various outcome measures, further supporting AMP's potential. These improvements in positive affect and well-being contrast with the often smaller and delayed gains seen with existing treatments. The findings' convergence with other positive affect-targeted interventions further strengthens their importance.

This study demonstrates that AMP enhances social reward processing and improves social connectedness in individuals with anxiety and depression. The findings suggest that targeting positive valence processes represents a promising therapeutic avenue. Future research should replicate these findings in larger samples, comparing AMP to active control conditions, and investigate whether changes in social reward responsivity directly mediate improvements in social connectedness. Further research should also explore potential moderators and mediators, such as diagnostic subtype or specific symptom profiles, and optimize the AMP intervention's delivery and duration.

This trial had a relatively small sample size, and the primary comparison was against a waitlist control, not an active treatment. The assessment of social connectedness relied primarily on self-report measures, and further research should incorporate objective measures of real-world social interactions. The study's design also limited exploration of the variation in responses based on specific diagnoses and individual differences in mechanisms underlying social disconnection. The majority-female sample also warrants further exploration of potential sex differences in AMP response. Finally, use of static images of smiling faces, rather than dynamic social cues, represents a potential limitation.