(PS5-38) Loneliness and Internalizing Symptoms of Anxiety and Depression over Time

Elevated levels of loneliness are thought to promote the development of anxiety, depression, and other internalizing symptoms, but most work has relied on cross-sectional analyses focused on traditional diagnostic categories or isolated symptom dimensions. Here we leveraged an explicitly hierarchical-dimensional approach and examined prospective associations between baseline variation in loneliness and longitudinal changes in broad and narrow internalizing-symptom dimensions in a risk-enriched sample of 226 emerging adults who were followed over a span of 2.5 years, with measurements taken at 0 months, 6 months, 24 months, and 30 months. By pairing timepoints at both 0 and 6 months, and at 24 and 30 months, we aimed to capture and analyze the progression of internalizing-symptom dimensions over distinct time intervals, providing an understanding of longitudinal and trajectory changes when experiencing loneliness over time. Results revealed that loneliness was significantly associated with increases in both broadband internalizing symptoms—the core cognitive and affective symptoms that cut across the emotional disorders—and the narrower dimensions of positive affect and anxious arousal that differentiate specific internalizing presentations across the 6-month follow-up period. The identical pattern was evident when using 24-month loneliness to predict changes in symptom intensity at 30-months. Although, when controlling for baseline 24-month, levels of the internalizing symptom sub-scales loneliness only predicted 30-months follow-up anxious arousal that differentiate specific internalizing presentations. These observations enhance the models linking personality to internalizing illness, highlight the centrality of neuroticism and negative emotionality to increase in transdiagnostic internalizing symptoms during a key developmental chapter. Findings also underscore the importance of addressing social connectedness and set the stage for developing more effective prevention and treatment strategies.