Comparison of positive and negative intrusive thoughts and experimental investigation of the differential effects of mood.

The similarity between positive and negative intrusive thoughts is considered for both recently occurring, personally relevant intrusions and for the same intrusions occurring during an experimental task involving self-monitoring. The results indicate that positive and negative intrusions differ in most respects. There was evidence that increasing the frequency of negative thinking is associated with a deterioration of mood. In a subsequent experiment, induced happy and sad moods were shown to differentially affect frequency of intrusions in a fashion consistent with mood congruency effects previously found in experiments on the effect of mood on memory. The implications of these findings for disorders involving the experience of intrusive thoughts such as OCD and depression are discussed.