Cannabis and Memory Study, Melbourne Neuropsychiatry Centre

The aim of this project is to determine the nature and emergence of memory deficits in cannabis users across the life span. We will discover how varying levels of exposure to cannabis during adolescence and adulthood impact upon brain function subserving verbal learning and memory processes and visuospatial working memory. The effects of frequency and duration of cannabis use on task performance, strategy utilisation, and engagement of appropriate neural systems, will be examined using neurocognitive assessments and functional neuroimaging. Differential engagement of inefficient learning and mnemonic strategies, together with altered activation of brain regions subserving these tasks, will qualitatively and quantitatively inform our understanding of the impact of cannabis use at different points in the lifespan and across the drug-using career. We have developed novel paradigms for functional brain imaging which allow us to directly test for the first time clinically significant hypotheses regarding the impact of cannabis use on memory-relevant brain function: 1) that long term and heavy cannabis use will lead to impaired activation of encoding and retrieval networks that are moderated differentially by frequency versus duration of cannabis use; 2) that the neural substrates of memory processing during the critical neurodevelopmental period of adolescence will be uniquely impacted by cannabis. In addition, this study will offer neurobiological insights into the role of cannabis as a potential precipitator of mental health problems, and importantly, inform the development of appropriate guidelines regarding hazardous levels of cannabis use in adolescents and adults and between the genders.

Approximately 100 participants were recruited for this project.

Time period: 2008-2011