The first of its kind, a study assessing the effects of cannabidiol (CBD) treatment on dog behavior, was recently published in Nature’s Scientific Reports.
Researchers in the study sought to investigate whether treatment with CBD derived from Cannabis sativa L. can reduce troubled and stress-related chronic behavior in shelter dogs by decreasing ‘displacing activities,’ ‘stereotyped or repetitive behavior,’ and ‘aggressive’ behavior.
Twenty-four shelter dogs were selected for the study in accordance with requirements enforced by the Animal Welfare and Protection Office of the Municipality of Rome. These dogs were chosen at random from a list of animals meeting the following selection criteria:
The researchers incorporated the fourth criterion to minimize the biased behaviors resulting from acute stress (i.e., rather than chronic stress).
Behavioral disorders exhibited by the selected dogs included:
Applying this inclusion criteria resulted in a total of 24 dogs – 20 neutered males, two unneutered males, and two spayed females – comprised predominantly of mixed-breed dogs (n = 18) with some (n = 6) dogs of purebred descent (Bull Terrier, n= 1; Bull Mastiff, n = 1; Italian Mastiff, n = 1; American Pit Bull Terrier, n = 3). The dogs were split alternately into two groups (treatment and control) of twelve.
For 45 days, each group received a daily oral administration of either of the following two treatments: extra virgin olive oil containing CBD-enriched extract from C. sativa L. (treatment group) or a placebo of extra virgin olive oil only (control group).
Behavioral patterns were observed for data collection at four designated time points: prior to either treatment (‘T0’), 15 days after starting treatment (‘T1’), 45 days after starting treatment (‘T2’), and 15 days following the end of treatment (‘T3’).
For behavioral data collection, observed behavioral patterns were classified into 12 categories: ‘activity,’ ‘aggressive behavior,’ ‘displacing activities,’ ‘stereotyped or repetitive behavior,’ ‘attention,’ olfactory investigation,’ ‘dominant behavior,’ ‘submissive behavior,’ ‘vocal communication,’ ‘affiliative behavior,’ ‘resting,’ and ‘playing.’
In particular, the researchers measured the degree of troubled and stress-related chronic behavior in terms of the extent of ‘displacing activities,’ ‘stereotyped or repetitive behavior,’ and ‘aggressive behavior’ displayed by the dogs.
‘Displacement activities’ were considered as irrational behavior patterns and/or body-care actions such as “body shaking, scratching, muzzle-licking, and auto-grooming.” ‘Stereotyped or repetitive behaviors’ included repetitive and compulsory behavioral patterns such as “pacing in circles, licking/biting, catching flies, coprophagy, object obsession, and self-mutilation”. Behavioral patterns including “growling, sideways glance, raising fur, curling lip, showing teeth, and dashing at bars” were defined as ‘aggressive behavior.’
The Friedman Test was used to compare the behavioral frequencies that were collected at the different time points within each of the two groups (i.e., intra-group analysis: T0, T1, T2, and T3 compared within each group, control and treated). Pairwise comparisons were subjected to Bonferroni correction. For comparisons between the control and treated groups (i.e., inter-group analysis: control versus treated), the Mann-Whitney U test was employed with a p-value < 0.05 deemed as significant.
A significant reduction in aggressive behavior towards humans was observed within the CBD-treated dogs over time (from T0 through to T3). In the pairwise comparisons between time-points within the treated group (i.e., T0 vs. T1, T0 vs. T2, T0 vs. T3), however, only the T0 to T3 comparison was considered to be significant.
Although significantly reduced aggression was observed within the treated group, the difference in the decrease of aggressive behavior observed between the two groups (treated vs. control) was not considered to be significant. Moreover, there was not a significant change in other stress-related behaviors (i.e., ‘displacing activities’ and ‘stereotyped or repetitive behaviors’).
In light of the non-significant findings, the authors conclude that these results ascribe Cannabis-derived extracts with a potential therapeutic effect in canines that warrants further investigation with larger sample sizes (i.e., for a more accurate analysis).