Temporal Dynamics of Affect, Smartphone Use, and Physical Activity in Individuals at Risk for Mood Disorders

BackgroundIdentifying how affect and daily behaviors influence each other is central to understanding mood disorder development. This study investigated how negative affect (NA), positive affect (PA), physical activity, and smartphone use influence one another in daily life, and whether familial risk or mood disorder history shape these relationships.MethodsOffspring of parents with bipolar disorder and control participants (n=128, Mage=37.8, 57% female) completed a 14-day experience sampling protocol measuring NA and PA five times a day with passive sensing of physical activity and smartphone use. We examined the effect of familial high risk (n=82) and history of mood disorders (recurrent: n=3, single: n=29, none: n=69) on within-person affect-behavior dynamics using Dynamic Structural Equation Modeling.ResultsResults showed a credible bidirectional relationship between physical activity and PA (physical activity → PA: β=0.06; 95% credibility interval [CrI], 0.02-0.09; PA → physical activity: β=.07; 95% CrI, 0.03-0.11), while NA exhibited no credible associations. Higher PA predicted decreased smartphone use (β=−.05; 95% CrI, −0.08-−0.02), while increased smartphone use was associated to subsequent elevated NA (β=.03; 95% CrI, 0.01-0.06). Familial risk status and recurrent mood disorders did not alter these bidirectional effects, but were associated with lower PA and higher NA on average (all p<0.001).ConclusionsFindings highlight PA as a key driver in the interplay between behavior and affect. Supporting PA through increased activity may help improve daily emotional experiences, even in those with elevated mood disorder risk.