The anticipated study duration was two years. Despite sustained recruitment efforts, the required number of eligible participants could not be enrolled within this timeframe. Therefore, the study was terminated.

Ethnic discrimination is associated with mental and physical health impairments. In view of the negative impact of discrimination on health, it is of great importance to investigate interventions to counteract these negative effects.

Based on findings of a pilot study (clinicaltrials.gov identifier: NCT04957966), this study investigates the effectiveness of a tailored ecological momentary music intervention to reduce biological (salivary cortisol, salivary alpha-amylase) and psychological (perceived stress, perceived ethnic discrimination) stress reactions after discriminatory and/or stressful events in the daily life of Turkish immigrant women (N = 50, age range 18-65 years).

An intra-individually randomized design will be used, i.e., participants will be assigned on a random basis either to intervention events (they can choose to listen to music for the duration of 10 or 20 minutes) or to control events (participants are instructed to not listen to music). The whole study period consists of 35 days with a baseline period (week 1), intervention period (week 2-4), and post period (week 5).

Ethnic discrimination (ED) represents a complex stressor that triggers psychobiological stress reactions (Pascoe & Smart Richman, 2009). Experienced chronically, ED can adversely affect mental and physical health (e.g., Lewis et al., 2015; Schmitt et al., 2014), most likely due to dysregulations of psychobiological stress systems (Chrousos, 2009; Schlotz, 2019). In this regard, women may be particularly affected as they face discrimination based on both ethnicity and gender more often compared to men (e.g., Harnois, 2014; Seaton & Tyson, 2019). Considering the resulting health impairments, it is of great importance to investigate strategies that can mitigate the occurring stress reactions and thereby contribute to health promotion. Therefore, we conducted a pilot study to test the feasibility of an ecological momentary music intervention aiming to reduce stress levels of affected individuals (clinicaltrials.gov identifier: NCT04957966). Based on the findings of the pilot study and power calculations, we will now conduct a larger main study. The primary aim of our study is to examine the effectiveness of an ecological momentary music intervention to reduce psychological and biological (cortisol, alpha-amylase) stress levels after stressful and/or discriminatory events in the daily life of chronically discriminated Turkish immigrant women.

We hypothesize that listening to self-selected, relaxing music after an event of acute stress and/or ethnic discrimination in daily life will result in stronger decreases of psychological (perceived stress, perceived ethnic discrimination) and biological (cortisol, alpha-amylase) stress levels compared to no music listening (immediate effect). Further, we expect a decrease in diurnal psychological and biological stress levels throughout the study period (intermediate effect).

The study consists of three phases: Baseline phase (week 1), intervention phase (week 2 to 4), post intervention phase (week 5).

During the baseline and post intervention phase, we will assess participants' psychological and biological stress fluctuations and perceived ethnic discrimination in daily life. Therefore, participants will be prompted three times a day (11:00 am, 3:00 pm, 7:00 pm) through a study app to answer questions on their momentary levels of stress, perceived discrimination, positive and negative affect, and their music-listening activities (time-contingent data entries). Additionally, whenever a stressful and/or discriminatory event occurs, participants will be instructed to initiate a data entry by themselves in order to report their momentary levels of stress, perceived discrimination, positive and negative affect, and to answer questions on the current situation. To investigate activities after such self-initiated, event-contingent data entries, the app will prompt the participants 20 minutes later for an additional data entry (post). As part of every time-contingent and event-contingent report, participants will provide a saliva sample for the analysis of biological stress markers: salivary cortisol levels as index of hypothalamic-pituitary-adrenal axis (HPA axis) activity, salivary alpha-amylase as index of autonomic nervous system (ANS) activity.

Every evening before going to bed, participants will complete a daily diary assessment via the study app. In this diary, participants will be asked about their current perceived stress, perceived discrimination, positive and negative affect, fatigue, and coping strategies. Additionally, they will be asked whether discriminatory or stressful events had happened over the course of the day and if so, to describe the event(s). This data entry will not require the collection of a saliva sample.

During the intervention phase (week 2 to 4), the sampling protocol will be the same as in the baseline and post intervention phase (i.e., time-contingent data entries, daily diary assessment, self-initiated event-contingent data entries, post). Additionally, participants will be randomly assigned (50:50) to either the intervention condition (listening to self-selected, relaxing music; participants can choose between the duration of 10 or 20 minutes) or the control condition (no music listening; participants are instructed to continue their pre-data entry activities) after every self-initiated event-contingent report. This intra-individually randomized study design will allow us to compare the effects of music listening vs. no music listening after stressful/discriminatory events on psychological and biological stress levels.

Inclusion Criteria:

• Turkish immigrants (1st or 2nd generation)
• Chronic ethnic discrimination (value of or above 104 on the Everyday Discrimination Scale)
• 18-65 years
• sex: female

Exclusion Criteria:

• Insufficient proficiency of the German language
• Body mass index (BMI) above 30 kg/m2
• Schizophrenia
• Substance-induced disorder in the past 2 years
• Chronic somatic diseases
• Medical conditions or medications known to affect endocrine or autonomic functioning
• Abuse of alcohol in the past 6 months
• Drug use in the past year, cannabis use in the past 14 days
• Pregnancy
• Breastfeeding
• Impaired hearing or absolute pitch

Data will be shared upon reasonable request.