Does cannabis adversely affect working memory function?

J. Fisk, R. Newcombe, M. Wareing, P. Murphy

Research output: Contribution to conferencePaper


Claims that cannabis-related impairments in verbal fluency, associative learning, processing speed, and forward and backward digit span are indicative of a general deficit in working memory functioning remain to be tested. Thirty-five cannabis users categorised by pattern of use over the past three months: ‘always’, ‘frequently’, and ‘occasionally’ were compared to 21 nonusers on complex span measures including reading, computation, and visuo-spatial working memory as well as simple word, digit and spatial span measures. Profile analysis with user group between participants, test modality (verbal, arithmetic, and spatial) and complexity (simple versus complex) within participants, revealed a significant effect of user group. Bonferroni corrected pairwise comparisons showed that both heavy user groups were impaired relative to occasional users and nonusers. Significant interactions revealed that the cannabis related deficit was greater on the complex measures and on the arithmetic and visuo spatial tasks. It remains unclear whether these effects are short term or long lasting.
Original languageEnglish
Publication statusPublished - 2003
EventBritish Psychological Society (BPS) Cognitive Section Conference -
Duration: 25 Dec 2003 → …


ConferenceBritish Psychological Society (BPS) Cognitive Section Conference
Period25/12/03 → …


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