An experimental study of prospective memory in obsessive-compulsive disorder.

The aim of the present study was to investigate prospective memory (PM) function in patients with obsessive-compulsive disorder (OCD). An event-based PM task was administered to 30 OCD patients and 30 healthy adult participants. For OCD patients, PM instruction produced significantly more cost in terms of reaction time (RT) during the ongoing task. A significant group-experimental condition interaction in ongoing task RTs was found, which suggests that PM instruction loaded an extra cost onto OCD patients' ongoing activities, and this was independent of the execution of the PM intention. Comparing the PM task RTs between patients and healthy adults also revealed a significant group difference. These results suggest that OCD patients experience difficulties during PM tasks, and these difficulties originate from overmonitoring the stimuli for PM cues.