Fluctuations in Daily Happiness and Nervousness Based on Depressive and Anxious Symptoms in Adolescents or Young Adults Across 3 Latin American Cities: Experience Sampling Study

Background: Experience sampling methods (ESMs) have been used in clinical research to collect data on emotional and behavioral states in real-life contexts among different populations. Although the use of ESMs in mental health has increased, it has not been applied to larger samples of young people in disadvantaged urban settings. Objective: This study aimed to determine the extent to which mood status scores (happiness and nervousness) vary during a week, as a function of having or not having symptoms of depression or anxiety, in a sample of adolescents and young adults in the cities of Buenos Aires, Bogotá, and Lima. A secondary objective was to identify factors associated with mood scores, including sociodemographics, quality of life, and daily activities. Methods: This study was part of the Building Resilience and Resources to Reduce Mental Distress in Young People in Latin America research program, which focuses on mental health resources for young people. Participants (n=143) aged 15‐24 years completed daily ESM assessments over a week using the mobile app, resulting in 5246 reports. Data were analyzed using descriptive analyses with 2-tailed t tests and chi-square tests, and multilevel linear regression was used to examine associations between depressive or anxiety symptoms, mood variability, and factors influencing mean mood. Finally, Spearman correlation assessed the relationship between happiness and nervousness. Results: The analysis revealed that depressive or anxiety symptoms were not significantly associated with increased variability in mood scores (happiness P=.40 and nervousness P=.84). However, males exhibited greater variability in happiness and nervousness scores (P<.001) than females. Additionally, young people showed higher variability in nervousness than adolescents (P=.02). Regarding average happiness scores, young adults reported higher average happiness than adolescents (β=.604; P=.003). Engaging in structured activities (eg, sports, music lessons, and dance classes) was associated with increased happiness (β=.266; P=.01). In contrast, instrumental activities (eg, cleaning, shopping, meal preparation, or taking medication; β=−.144; P=.02) and work-related tasks (β=−.205; P=.01) were linked to lower happiness and higher nervousness (β=.387; P<.001). Quality of life was positively correlated with happiness (β=.486; P<.001) and negatively correlated with nervousness (β=−.273; P=.005). Finally, as for average scores, a strong negative correlation was found between happiness and nervousness (rs=−0.92; P<.001). The simple multilevel analysis showed that for each point of happiness, nervousness decreased by 0.45 points (95% CI −0.48 to −0.42; t₃=−41.7; P<.001; SE 0.01). Conclusions: Our study reveals that depressive and anxiety symptoms do not significantly affect the variability in predicted happiness and nervousness scores. However, we observed that demographic factors, such as gender and age, play a role in emotional variability.