Heavy Cannabis Consumers Lack Coordination, Study Finds

Image credit: iStock
Heavy cannabis consumers have low levels of coordination, according to a study published in Addiction Biology.
The study tested the coordination of 47 participants, 21 of whom consumed cannabis regularly and 26 who didn’t.
Compared to the control participants, the cannabis consumers scored significantly lower in the coordination tests.
These tests assessed how well the participants could perform standard coordination behaviors like walking heel-to-toe, standing on one leg, and touching thumbs to fingers.
The researchers behind the study say that such low coordination scores could be linked to risk factors for psychosis.
Head, shoulders, knees, and stoned
To get their findings, the researchers – who were from the universities of Heidelberg, Saarland, and Saarbrücken in Germany – first recruited “heavy cannabis users” who consumed the drug at least 10 days per month over the recent 24 months. The other participants could only join the control group if they had smoked less than 10 joints in their lifetimes and had no cannabis use in the 12 months prior to the study.
All participants were asked to perform standard coordination tasks (opening and closing of fists, walking back and forth, etc.) and undergo an MRI brain scan.
The heavy cannabis users scored significantly lower in the coordination tasks than the control group. The researchers could even associate the cannabis group’s low motor coordination and complex motor task scores with the age of onset of their THC use.
“Our second finding supports the assumption that cannabis, presumably through stimulation of cannabinoid receptors (e.g., CB1 receptor), can impair the sensorimotor system, both acutely and in the long term,” the researchers wrote in their paper.
The MRI scans of the cannabis consumers also showed “abnormal” regional homogeneity in the regions of the brain associated with sensorimotor and executive control and visuomotor integration.
“These findings provide new evidence of cannabis-associated functional dysregulation of sensorimotor, executive and visual networks that may contribute to the development of NSS [neurological soft signs] in at-risk populations,” the authors concluded.
“Finally, given convergent findings in manifest psychotic disorders, the current data could suggest an HCU [heavy cannabis user] endophenotype that may present with cumulative risk factors for psychosis.”