Anticipating undesired outcomes: The role of outcome certainty in the onset of depressive affect

We propose that the manner in which people anticipate future events influences the onset of depressive affect. In particular, we suggest that people are likely to experience depressive affect when they perceive highly aversive future events to be inevitable, i.e., 100 percent certain to occur. To test this hypothesis, we led participants to believe that the likelihood of experiencing an aversive event later in the experiment was either 0, 25, 50, 75, or 100%, while holding constant perceived uncontrollability. Results verified the notion that anticipating an undesired outcome that is inevitable produces significant increases in depressive affect. More specifically, a discrete increase in depression was observed when certainty reached 100% relative to anticipated likelihoods of 75, 50, 25, and 0%. Hence, depression did not simply increase linearly with increasingly high likelihoods that the aversive outcome would occur, but rather was a function of certainty. A similar but less pronounced pattern of findings was observed for increases in anxiety and hostility, indicating that these affects tended to co-occur with depressive affect. Overall, when a negative outcome is certain to occur, individuals may give up on the possibility of being spared the outcome and may become depressed as a result.