The effects of multi-tasking on psychological stress reactivity in recreational drug user of cannabis and MDMA

Background: Cannabis and MDMA use is associated with psychobiological and neurocognitive deficits. Assessments of the latter typically include tests of memory and everyday cognitive functioning. However, to date little attention has been paid to effects of drug use on psychological stress reactivity. We report three studies examining the effects of recreational use of cannabis and MDMA on mood and psychological responses to multi-tasking using a cognitively demanding laboratory stressor that provides an analogue for everyday situations involving responses to multiple stimuli. Methods: The effects of the Multi-tasking Framework on mood and perceived workload were assessed in cannabis (N=25), younger (N=18) and older (N=20) MDMA users and compared with non-target drug controls. Results: Compared with respective control groups, cannabis users became less alert and content and both MDMA groups became less calm following acute stress. Unexpectedly the stressor increased ratings of calm in cannabis users. Users also scored higher than their controls with respect to ratings of resources needed to complete the multi-tasking framework. Conclusions: These findings show, for the first time, that recreational use of cannabis and MDMA, beyond the period of intoxication, can negatively influence psychological responses to a multi-tasking stressor and this may have implications for real-life situations which place high demands on cognitive resources.