Mechanisms of behavioral activation for late adolescents: Positive reinforcement mediate the relationship between activation and depressive symptoms from pre-treatment to post-treatment.

BACKGROUND: It is suggested that there is some support for notion that frequency of activity can lead to improved mood in behavioral activation, but this research is relatively imprecise. We investigated whether positive reinforcement mediates the relationship between activation and alleviation of depressive symptoms
METHODS: Late adolescents with sub-threshold depressive symptoms participated in the study. We conducted an intervention using behavioral activation with the participants. Then, pre-and post-treatment results of behavioral activation were compared. We used mediation analysis using the bootstrapping method to examine whether changes in reinforcement mediated the relationship between changes in activation and improvements in depressive symptoms.
RESULTS: Participants improved significantly at the post-intervention assessment, compared to the baseline assessment. Results of mediation analysis indicated that reinforcement significantly mediated the relationship between activation and depressive symptoms, whereas activation alone had no a direct effect on depressive symptoms. LIMITATIONS: Further studies with more diverse samples of participants are required in order to generalize the results of this study to more diverse populations.
CONCLUSIONS: The study provides the first full mediational test of behavioral activation model including both measures of activation and positive reinforcement, and we found support for behavioral activation's presumed mechanism of action that contact with positive reinforcement mediates the relation between activity and depression.