Real-life validation of reduced reward processing in emerging adults with depressive symptoms

Subclinical symptoms of depression are common in emerging adults. Anhedonia is one such symptom that specifically puts one at risk for developing clinical depression. Recently, important progress has been made in elucidating the underlying neurobiology of anhedonia. This progress rests on many experimental studies examining how subjects with depressive symptoms respond to anticipating and consuming rewarding stimuli. Translating these findings to real-life reward processing dynamics is an important next step in order to guide fine-tuning of preventive treatments. We propose that the Experience Sampling Methodology (ESM) represents a useful tool in addressing this issue. ESM requires individuals to carry a device that beeps at semirandom moments, inviting them to fill out a short questionnaire on mood, context, and behavior. Using this methodology, we aimed to decompose the construct of reward processing into its daily life dynamics, by investigating how positive affect (PA), reward anticipation and active behavior influence each other over time. A group of emerging adults (aged 16-25) was included, of which two-thirds presented with subclinical depressive symptoms. Associations between PA, reward anticipation and active behavior manifested in the flow of daily life. Depressive symptoms were significantly associated with reduced time-lagged associations between reward anticipation and active behavior (β = -.005, p = .006) and active behavior and reward anticipation (β = -.002, p = .027). The moderating effect of depressive symptoms on the time-lagged association between reward antici-pation and PA approached significance (β = -.002, p = .051). These findings represent an important step in translating experimental knowledge on reward processing into daily life processes.