(Photo credit: Mladen Antonov/AFP via Getty Images).
A new double-blind, placebo-controlled pilot study found that a hemp extract rich in cannabidiol (CBD) and cannabidiolic acid (CBDA) increased resting and reduced activity among shelter dogs with histories of reactive or anxiety-related behavior, with the changes appearing most pronounced at night.
The study, conducted by researchers from Université Paris Nanterre, Agir pour la Vie Animale, Université Sorbonne Paris Nord, UniLaSalle and Cornell University, is currently available as a preprint and has not yet undergone peer review.
Researchers enrolled 17 dogs housed at an animal shelter in Normandy, France. Seven received a CBD- and CBDA-rich hemp extract, while 10 received a placebo. The dogs were treated for approximately four weeks, with the cannabinoid group receiving an eventual dose of 6 ± 1.4 milligrams per kilogram of body weight per day.
The team evaluated the dogs in two ways. Stress-related behaviors were recorded on video before and after treatment, while a subset of nine dogs — four receiving CBD/CBDA and five receiving placebo — wore accelerometer collars that continuously tracked resting and low, medium and high activity.
Video analysis did not find a statistically significant treatment effect. However, researchers observed several trends in the CBD/CBDA group, including more resting, less locomotion and fewer postural transitions. Of the three treated dogs that displayed repetitive locomotion at the beginning of the study, two no longer displayed the behavior after treatment. No comparable change occurred among the five placebo dogs exhibiting repetitive locomotion.
The accelerometer data produced stronger results.
Researchers found significant differences between the CBD/CBDA and placebo groups over time across all four measured activity levels. Dogs receiving the cannabinoids showed increased resting and reductions in low, medium and high activity, while the placebo group remained relatively stable.
Median resting time in the CBD/CBDA group increased from 46.2 minutes per hour at baseline to 52.8 minutes following treatment. Median low activity declined from 5.53 to 3.30 minutes per hour, medium activity from 6.14 to 3.71 minutes and high activity from 0.30 to 0.12 minutes.
The differences appeared especially noticeable from approximately 5 p.m. through 6 a.m., when environmental stimulation at the shelter was generally lower. Researchers said this pattern may indicate that the dogs were experiencing reduced vigilance and reactivity and were better able to rest, rather than simply being sedated.
The initial dose was higher, at approximately 10 mg/kg per day, but researchers reduced it after possible adverse effects emerged. One dog developed hypersalivation, an unusual reduction in activity and possible genital swelling and was removed from the study. The remaining dogs appeared to tolerate the reduced dosage well.
Researchers cautioned that the study was small and involved considerable differences between individual dogs, limiting the strength of the conclusions. They said larger studies are needed to determine optimal dosing and identify which dogs may be most likely to benefit.
Overall, the authors said the findings were more consistent with a targeted calming effect than generalized sedation, potentially allowing stressed dogs to reduce vigilance and rest more effectively. They suggested CBD/CBDA could eventually serve as a complementary tool alongside environmental enrichment, improved housing and behavioral interventions for shelter dogs.
