Introduction: Prospective memory (PM) refers to remembering to execute a planned intention in the future. It can be divided into event- and time-based, according to the nature of the PM cue. Event-based PM cues can be classified as focal or non-focal. Patients with schizophrenia (SCZ) have been found to be impaired in both event- and time-based PM. PM has been found to be improved by implementation intentions, which is an encoding strategy in the format of "if X then Y". This study examined the effect of implementation intentions on a non-focal event-based and a time-based PM task in patients with SCZ.
Methods: Forty-two patients with SCZ and 42 healthy controls were allocated to either an implementation intention or a control PM instruction condition and were asked to complete two PM tasks.
Results: Implementation intentions was found to improve performance in both the non-focal event-based and time-based PM tasks in patients with SCZ and healthy controls, with no costs to the ongoing task. The improvement in time-based PM performance in the implementation intentions condition was partially mediated by the frequency of clock checking behaviour.
Conclusions: Implementation intentions can facilitate PM performance in patients with SCZ and has the potential to be used as a clinical intervention tool.
Keywords: Implementation intentions; non-focal event-based prospective memory; schizophrenia; time-based prospective memory.