Longitudinal changes in cognition in young adult cannabis users.
INTRODUCTION
Adolescent cannabis use (CU) is associated with impaired attention, executive function, and verbal learning/memory. These associations are generally observed in cross-sectional studies. Longitudinal studies of cannabis users are lacking.


METHOD
The present study examines associations between CU and cognition over time in chronic daily adolescent-onset CUs, as compared to nonusing controls. Both groups completed a neuropsychological battery at study intake and again 2 years later.


RESULTS
Baseline group differences have been published and indicated deficits in verbal learning and memory, motivated decision-making, planning, and working memory in CUs. In this follow-up report, the longitudinal performance of users is compared to that of sustained nonusers using the same battery. At follow-up, the majority of CUs continued to report regular and heavy cannabis use. Relative impairments in the domains of working memory, planning and verbal memory remained stable, suggesting that these are enduring vulnerabilities associated with continued CU during young adulthood. Improvements in motivated decision-making were evident in both groups. In addition, CUs demonstrated relatively better performance on short-duration speeded tasks. An earlier age of CU onset was associated with poorer verbal learning and memory and planning performance over time.


CONCLUSIONS
Verbal learning and memory and planning processes, as well as their neural correlates, merit further scrutiny within etiological models of cannabis-induced cognitive impairments.
['Becker|Mary P|MP|', 'Collins|Paul F|PF|', 'Schultz|Ashley|A|', 'Urošević|Snežana|S|', 'Schmaling|Brittany|B|', 'Luciana|Monica|M|']
D001288:Attention D003071:Cognition D003657:Decision Making D056344:Executive Function D005260:Female D005715:Gambling D006801:Humans D008137:Longitudinal Studies D008297:Male D002189:Marijuana Abuse D008385:Marijuana Smoking D008569:Memory Disorders D008570:Memory, Short-Term D009042:Motivation D009483:Neuropsychological Tests D011597:Psychomotor Performance D014706:Verbal Learning D055815:Young Adult
cannabis Adolescence executive function memory neurocognition