Cannabis-related deficits in real-world memory

Background
Research shows that cannabis users exhibit deficits in prospective memory (PM) and executive function, which persist beyond acute intoxication. However, many studies rely on self-reports of memory failures or use laboratory-based measures that may not mimic functional deficits in the real world. The present study aimed to assess real-world memory functioning.
Method
Twenty cannabis-only users and 20 non-illicit drug users were recruited. Participants completed a substance use inventory and a mood scale, followed by a non-immersive virtual reality task assessing PM and executive functioning. The task involved the participant playing the role of an office worker for the day and performing routine office duties. A number of subscales were used to assess facets of executive function (planning, adaptive thinking, creative thinking, selection, prioritisation) and PM (time-based, event-based and action-based PM).
Results
Multivariate analysis of variance revealed cannabis users performed worse overall on the task, with poor performance on the planning, time-based PM and event-based PM subscales. In addition, indices of cannabis (length, dose, frequency, total use) were correlated with performance on these three subscales.
Conclusions
The present study expands on previously established research, providing support for the cannabis-related deficits in PM and executive functioning, and the role of different aspects of cannabis use in these deficits.

Citation:
Montgomery, C., Seddon, A. L., Fisk, J. E., Murphy, P. N. and Jansari, A. (2012) 'Cannabis-related deficits in real-world memory'. Human Psychopharmacology: Clinical and Experimental, 27(2), pp. 217-225, doi:10.1002/hup.1273.