Time since cannabis use cessation: implications for mood and IQ performance

P. Erwin, P. Murphy

Research output: Contribution to conferencePaperpeer-review


Background Mood disturbance and impaired cognitive performance have been linked to cannabis consumption. This study examined the relationship between these areas of functioning and time since last cannabis use. Method The sample comprised cannabis users (n = 61, 35 female, median lifetime consumption = 121.0 joints, semi-interquartile range = 1,028 joints), and controls (n = 36, 19 female). A mood adjective rating scale yielded measures of depression, anxiety, and arousal. IQ. related performance was measured by Sets D and E of Ravens Progressive Matrices. Premorbid intelligence was assessed by the National Adult Reading Test (NART). A structured interview questionnaire obtained measures of cannabis use. Results For users, the period since last cannabis use (median = 68 days, semi-interquartile range = 317.5 days) formed the dependent variable (DV) in a hierarchical regression where Block 1 contained the mood scores as predictors, with Set E scores being added in Block 2. Both blocks were significantly predictive of the DV, with Block 2 predicting 23.1% of its variability. Block 2 marginally failed to predict significantly more variability than Block 1. All predictors showed a negative relationship to the DV, with only depression not showing a significant or marginally nonsignificant relationship. Inter-group comparisons controlled for age and NART scores revealed no significant differences. Discussion Time since last use of cannabis was significantly related to reductions in anxiety, whilst being related to a declining trend in arousal and IQ. related performance. These effects do not appear to be short-term withdrawal phenomena, and require further research.
Original languageEnglish
Publication statusPublished - 2008
EventInternational Congress of Psychology - Berlin, Germany
Duration: 25 Dec 2008 → …


ConferenceInternational Congress of Psychology
Period25/12/08 → …


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