NCT07155941

Ecological Momentary Intervention for Reward in Anhedonia

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 60 (estimated)
• Sponsor: Philipps University Marburg · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The present study evaluates a two week ecological momentary intervention (EMI) in reducing anhedonia and psychological distress (i.e. elevated depression, stress and anxiety). Participants in the experimental group complete three daily exercises targeting reward-related processes, including positive mental imagery, savoring, gratitude, taking ownership for positive experience, and silver lining. These components were selected to improve reward anticipation as well as reward consumption and reward learning as the underlying mechanisms of anhedonia. An active control group receives progressive muscle relaxation training, matched in format and frequency. Exercise units are presented using audio recordings via smartphone app.

Detailed description

Anhedonia, the diminished ability to experience positive emotions such as pleasure, is a clinically relevant condition central to depression and frequently observed across a range of other psychological disorders including anxiety disorders or chronic stress. Despite its prevalence and impact on quality of life, effective interventions specifically targeting anhedonia remain limited. Standard cognitive-behavioral therapies (CBT) often reduce negative affect (e.g., sadness, anxiety) but tend to be less effective in enhancing positive affect. Moreover, anhedonia has been proposed as a potential limiting factor in the efficacy of exposure-based treatments for anxiety disorders, underscoring the need for low-threshold interventions that directly target reward-related deficits. At the core of anhedonia lies impaired reward processing, which involves multiple phases: (1) reward anticipation (wanting), (2) reward consumption (liking), and (3) reward-based learning. Individuals with elevated anhedonia often show deficits across these domains, leading to reduced engagement in rewarding activities and motivational impairments. Therefore, effective interventions should aim to strengthen these specific facets of reward functioning. Emerging approaches such as Positive Affect Treatment (PAT) have demonstrated promising effects by combining components like positive mental imagery, savoring, self-reinforcement (i.e., taking ownership of positive experiences), and cognitive reframing (e.g., silver lining techniques). Complementary evidence suggests that gratitude-based interventions can enhance well-being and buffer against stress, based on the idea that gratitude and negative affect are partially incompatible. Building on these findings, the current study tests a two-week ecological momentary intervention (EMI) designed to enhance reward processing and reduce anhedonia in daily life. The intervention is delivered via the smartphone app m-Path and comprises three brief training units per day. These include a combination of audio-guided exercises and ecological momentary assessments (EMA) capturing mood, activity, and psychological symptoms. The exercises target positive mental imagery, savoring, gratitude, silver lining, and taking ownership of positive experiences-each mapped onto distinct components of reward processing. EMI formats offer the advantage of flexibility and integration into everyday contexts without requiring direct clinician contact. Participants are randomly assigned to either the reward-focused intervention group or an active control group. The control group receives a structurally equivalent two-week training consisting of progressive muscle relaxation (PMR) exercises, also delivered via the m-Path app. PMR is an established stress-reduction technique and serves as an active comparator matched in format, frequency, and duration. The control group completes two audio-guided PMR sessions per day and one brief reflection unit each evening. It is hypothesized that the reward intervention will (a) reduce anhedonia and psychological distress more effectively than PMR and (b) lead to specific improvements in reward processing.

Conditions

• Anhedonia
• Anxiety
• Stress
• Depression

Interventions

Type	Name	Description
BEHAVIORAL	Training of reward processing/sensitivity	Participants in the experimental group complete a two-week ecological momentary intervention (EMI) consisting of three brief training units per day, each delivered via a smartphone. The exercises target different aspects of reward processing and are scheduled at specific times throughout the day. The morning unit (to be completed between 10:00 and 12:00 a.m.) involves a positive mental imagery task guided by audio recording. Participants are guided to vividly imagine a future situation with the most pleasurable and meaningful outcome possible. They are encouraged to mentally activate all senses, thoughts, and emotions associated with this scenario. The afternoon unit (to be completed between 3:00 and 5:00 p.m.) consists of a savoring exercise guided by audio recording. Participants recall a positive experience from the past and are instructed to re-experience and savor it mentally by focusing on its sensory details, emotional quality, and personal significance. The evening unit (to be
BEHAVIORAL	Relaxation Training (PMR)	Participants in the control group complete a two-week progressive muscle relaxation (PMR) program designed to match the reward training in both frequency and duration. The intervention consists of three daily units, each delivered via a smartphone app and guided by audio recordings. The first and second units of each day consist of short audio-guided PMR sessions (approximately 5 minutes each). These exercises systematically guide participants through alternating tension and relaxation of different muscle groups to promote physical and mental relaxation. The third unit of the day focuses on reflection. Participants are asked to evaluate their experiences with the relaxation exercises over the course of the day. They reflect on their ability to engage with the exercises, the perceived effects (e.g., feelings of relaxation), any difficulties they encountered, and strategies to enhance the effectiveness of relaxation in their daily life beyond the intervention.
OTHER	Psychoeducation	All participants receive a psychoeducation session on the day before the respective intervention starts. In this session, a graduate-level study team member introduces the rationale behind the training (PMR or reward-training), and demonstrates each exercise. Participants also practice each task.

Timeline

• Start date: 2025-06-18
• Primary completion: 2026-01-01
• Completion: 2026-01-01
• First posted: 2025-09-04
• Last updated: 2026-01-09

Locations

1 site across 1 country: Germany