Benefits of the "worst-case scenario": a multi-level examination of the effects of confronting the feared outcome during imagery-based exposure.

Exposure therapy is an efficacious treatment for anxiety-related disorders. Yet, fear often returns after treatment. Occasional reinforcement, in which the feared stimulus is intermittently presented during extinction, increases safety learning and slows fear renewal in conditioning paradigms and analogue samples, but no studies to date have examined this strategy in clinical samples. The present study examined the effects of vicarious occasional reinforcement on fear renewal in a snake-phobic sample across multiple levels of analysis. Fear was intermittently reinforced by providing reminders of the feared outcome (a snake bite) throughout a two-session analogue video exposure manipulation. Snake-phobic adults were randomized to one of three conditions: a single-cue [S], multiple-cue [M], or multiple-cue+fear-outcome [M+FO] exposure group. Results showed the three groups did not significantly differ in threat expectancy or attentional bias for threat at follow-up. Despite sustained anxiety, however, the M+FO condition completed significantly more steps on a visual avoidance task at follow-up than the M and S conditions and heightened mean distress during exposure mediated this effect. The M and S groups did not significantly differ in visual avoidance at follow-up. These findings suggest incorporating reminders of the feared outcome into exposure may be an effective strategy for increasing inhibitory retrieval.