Although cognitive theory predicts that depression-prone individuals possess negative information-processing biases, the reliable detection of this type of cognitive vulnerability has proved difficult. The present study tested the idea that depression-relevant, cognitive biases are often elusive because at-risk individuals actively try to suppress depressive thinking. The study employed a novel measure of information processing that involves the identification of words imbedded in a letter grid. A cognitive load - designed to disrupt thought suppression - caused a negative attentional shift among individuals at risk for depression (because of a previous episode), leading them to identify negative words at a rate equivalent to currently dysphoric participants. The hypothesised role of mental control was further supported by the fact that the load-related, attentional shift was strongly associated with chronic thought suppression.