We propose a delineation of mediational effects derived from cross-sectional designs into the terms temporal and atemporal associations to emphasize time in conceptualizing process models in clinical psychology. The general implications for mediational hypotheses and the temporal frameworks from within which they may be drawn are discussed.

Introduction Anxiety and depression are often comorbid conditions, but there is uncertainty as to how this comorbidity develops. Thus, in three studies, we attempted to discern whether anhedonia may be a key linking factor between anxiety and depression. Methods Three studies asked participants about their symptoms of anxiety and depression: in Study 1, 109 participants completed measures of anxiety, depression, activity avoidance, and perceived enjoyability and importance of avoided activities; in Study 2, 747 participants completed measures of anhedonia, anxiety, depression, and defensiveness; in Study 3, 216 participants completed measures assessing the same constructs as in Study 2 at four time-points (ranging 11 months in span). Results In Study 1, symptoms of anxiety and depression were only positively related in individuals who relinquished potential enjoyment due to their anxiety-related avoidance; in Study 2, the indirect effect of anhedonia helped explained how anxiety symptoms imparted risk onto depressive symptoms; and in Study 3, anxiety led to anhedonia and then depression over time and anhedonia led to anxiety and then depression at both 5 and 11 months. Limitations The manuscript is limited by the use of a student sample in study 2, cross-sectional methods in studies 1 and 2, and reliance on self-ratings in studies 2 and 3. Conclusions Anxiety may devolve into depression through anhedonia, such that anxious individuals begin to lose pleasure in anxiety-provoking activities, which results in the development of other depressive symptoms.

Anhedonia, or the loss of interest and/or pleasure, is a core symptom of depression. Individuals experiencing anhedonia have difficulty motivating themselves to pursue rewarding stimuli, which can result in dysfunction. Action orientation is a motivational factor that might interact with anhedonia to potentially buffer against this dysfunction, as action-oriented individuals upregulate positive affect to quickly motivate themselves to complete goals in the face of stress. The Effort-Expenditure for Rewards Task (EEfRT) is a promising new method for examining differences in motivation in individuals experiencing anhedonia. In the EEfRT, participants choose either easier tasks associated with smaller monetary rewards or harder tasks associated with larger monetary rewards. We examined the relationship between action orientation and EEfRT performance following a negative mood induction in a sample with varying levels of anhedonia. There were two competing hypotheses: (1) action orientation would act as a buffer against anhedonia such that action-oriented individuals, regardless of anhedonic symptoms, would be motivated to pursue greater rewards despite stress, or (2) anhedonia would act as a debilitating factor such that individuals with elevated anhedonic symptoms, regardless of action orientation, would not pursue greater rewards. We examined these hypotheses via Generalized Estimating Equations and found an interaction between anhedonia and action orientation. At low levels of anhedonia, action orientation was associated with effort for reward, but this relationship was not present at high levels of anhedonia. Thus, at low levels of anhedonia, action orientation acted as a buffer against stress, but at high levels, anhedonia debilitated action orientation so that it was no longer a promotive factor.

Depression has been linked to multiple forms of aggressive behavior in college students; however, it is unclear which aspects of depression explain this connection. Anhedonia, defined as the loss of interest and/or pleasure in previously enjoyed activities, may provide unique information about relationships between depression and aggression. Using cross-sectional data from two independent samples of college students ( N = 747 and N = 736 for Study 1 and Study 2, respectively), we examined whether anhedonia helped explain the relationship between broader depressive symptoms and different forms of aggressive and antisocial behavior. Anhedonia accounted for variance in both self-directed aggression and antisocial behavior independent of gender, hostility, anger, other depressive symptoms, and cognitive distortions (Study 2). In addition, there were significant indirect effects of depressive symptoms on self-directed aggression (Studies 1 and 2) and antisocial behavior (Study 2) via anhedonia. Hypotheses involving other-directed aggression received mixed support, with anhedonia atemporally associated with other-directed aggression independent of broader depressive symptoms in Study 1, but not in Study 2. The current findings suggest that anhedonia is an important individual difference that helps explain the relationship between depression and aggressive and antisocial acts and that anhedonia may be differentially associated with various types of aggressive and antisocial behavior.

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