Eyewitness recall, lineup identification, and verbal and visual memory among chronic cannabis users after a minimum of 24-h abstinence

Research has begun to investigate the reliability of cannabis-intoxicated eyewitnesses; however, no studies have evaluated eyewitness memory among chronic cannabis users after a minimum 24-h abstinence. This study compared cannabis users' (n = 23) and nonusers' (n = 26) eyewitness recall/identification and investigated the relationship between eyewitness memory and neuropsychological functioning. Users demonstrated better visual recognition relative to nonusers. Groups' neuropsychological performance was otherwise similar. Regarding eyewitness memory, users recalled more inaccurate crime details when cued, whereas total accurate and inaccurate details recalled were similar. Neither user status, lineup type, their interaction, nor education were credible predictors of lineup identification accuracy. Verbal memory performance and years of education, but not user status, credibly predicted eyewitness recall accuracy. Findings suggest that cannabis-user eyewitnesses may require special consideration regarding police interviewing techniques; however, additional research is necessary to determine the conditions in which chronic cannabis users are reliable or unreliable eyewitnesses.