4 - (SYM 26) Not All Bad Days Lead to Use: Depression and Anxiety Symptoms Predict Daily Affect Profiles Among Young Adults Who Use Alcohol and Cannabis

The affect regulation hypothesis posits that individuals use substances to cope with negative emotions, yet support remains inconsistent. A critical question is whether depression and anxiety amplify momentary affect-use links or shape broader emotional contexts. Traditional research focused on unidimensional affect, overlooking arousal patterns that better capture the daily experiences motivating substance use. This study tested whether depression and anxiety predict young adults' likelihood of experiencing distinct daily affective profiles, and whether symptoms moderate associations between affective patterns and alcohol and cannabis use.

Young adults (N=154; 57.8% female; 72.7% non-Hispanic White) with recent heavy episodic drinking and alcohol-cannabis co-use completed baseline assessments of depression and anxiety, followed by 14 daily surveys (1,878 person-days). Daily affect was characterized using five latent profiles: High Arousal Positive, Low Arousal Positive, Mixed Affect, Low Reactivity, and Undifferentiated Negative Affect. Error-adjusted marginal regression models tested symptom effects on profile membership and moderation.

Depression predicted greater likelihood of Low Reactivity Days (blunted responding; OR=1.45) and Undifferentiated Negative Affect Days (OR=1.29), and lower likelihood of High Arousal Positive Days (OR=0.65) and Mixed Affect Days (OR=0.64). Anxiety predicted greater likelihood of Mixed Affect Days (emotional volatility; OR=1.36) and lower likelihood of Low Reactivity Days (OR=0.63). Neither depression nor anxiety moderated associations between affective profiles and substance use.

Findings challenge assumptions that depression and anxiety amplify momentary affect-driven substance use. Instead, internalizing symptoms function as distal factors shaping broader emotional landscapes in which young adults navigate substance decisions. Depression was associated with emotional flattening and sustained negative affect; anxiety with heightened volatility. These patterns did not strengthen affect-use coupling. Results call for theoretical refinement of the affect regulation hypothesis, moving beyond valence-based models toward understanding how chronic internalizing symptoms create emotional contexts influencing substance use through pathways other than acute affect regulation. Interventions targeting emotion regulation may benefit young adults with co-occurring symptoms and substance use.