Inhibitory control in people who self-injure: evidence for impairment and enhancement

Self-injury is often motivated by the desire to reduce the intensity of negative affect. This suggests that people who self-injure may have difficulty suppressing negative emotions. We sought to determine whether self-injuring individuals exhibit impaired inhibitory control over behavioral expressions of negative emotions, when responding to images containing aversive emotional content. Self-injuring participants and healthy controls completed a Stop Signal Task in which they were asked to judge the valence (positive or negative) of images. Three types of images depicted emotional content (neutral/positive/negative). A fourth type depicted self-cutting. An unpredictable "stop signal" occurred on some trials, indicating that participants should inhibit their responses to images presented on those trials. Compared to controls, self-injuring participants showed poorer inhibition to images depicting negative emotional content. Additionally, they showed enhanced inhibition to self-injury images. In fact, self-injuring participants showed comparable response inhibition to cutting images and positive images, whereas controls showed worse inhibition to cutting images compared to all other types of images. Consistent with the emotion regulation hypothesis of self-injury, people who self-injure showed impaired negative emotional response inhibition. Self-injuring individuals also demonstrated superior control over responses to stimuli related to self-injury, which may have important clinical implications.