Scientists studied 47,000 dogs on CBD and found a surprising behavior shift

"Behaviorally, dogs given CBD products for multiple years are initially more aggressive compared to dogs not receiving those products, but their aggression becomes less intense over time," said senior author Dr. Maxwell Leung, an assistant professor and the director of Cannabis Analytics, Safety and Health Initiative at Arizona State University.

"This long-term behavioral change highlights the potential of CBD as a therapy for canine behavioral issues," added co-author Dr. Julia Albright, an associate professor at the College of Veterinary Medicine at the University of Tennessee.

Large-Scale Study Tracks CBD Use in U.S. Companion Dogs

This research represents the most extensive effort so far to investigate CBD use among pet dogs in the US. The team relied on the Dog Aging Project, a long-term community science initiative in which owners provide yearly updates on their pets' diet, lifestyle, health, and living conditions. A total of 47,355 dogs were included, with data collected through annual surveys between 2019 and 2023.

Owners detailed how often their dogs consumed CBD or hemp products. Frequent users received a supplement every day, while infrequent users were given supplements less often than once a day. Owners could also indicate that their dogs had never been given CBD.

Who Receives CBD? Age, Health Conditions, and Household Patterns

Clear patterns emerged when the researchers examined which dogs were most likely to be given CBD. "In our sample, 7.3% of the companion dogs in the US have been given CBD and hemp products," said Leung. Of these, 2,759 dogs (5.8%) were frequent users. Dogs receiving the supplements tended to be older; on average, they were three years older than dogs that did not receive CBD.

Several health issues were linked to higher CBD use. The strongest association was seen in dogs with dementia (18.2%), followed by those with osteoarthritis joint problems (12.5%) and those diagnosed with cancer (10%).

Dogs living in states where human medical cannabis is legal were also more likely to receive CBD. This may reflect how owners' attitudes toward cannabis influence their decisions for their pets. Male dogs were given CBD more often, with a 9% higher likelihood than female dogs. However, activity levels did not differ significantly between dogs that used CBD and those that did not.

Behavioral Changes Suggest a Gradual Calming Effect

The study also documented behavioral differences. Dogs that received CBD for extended periods were described as having lower-than-average aggression levels compared to dogs with no CBD use. This pattern suggests that CBD could play a role in reducing aggressive behaviors. Other behavioral traits, such as agitation or anxiety, did not show the same association. "Most canine aggression is related to underlying stress or anxiety -- a fight or flight response that kicks in. It is unclear why only aggression but not other types of anxious or agitated behaviors seemed to be improved with CBD treatment," Albright said.

Research Gaps, Safety Concerns, and the Need for Better Data

The team noted that the study did not explore the biological reasons behind these behavioral shifts, and controlled research will be necessary to confirm CBD's calming potential. They also pointed out several limitations in the available data, including possible owner bias and the lack of detailed information about CBD dosage, product formulations, administration methods, and sources. "At this point, we do not have a complete picture about the behavioral treatment plan," Albright pointed out.

Owners considering CBD for their dogs should purchase reliable products and be cautious with dosing, since CBD can cause side effects such as gastrointestinal upset and diarrhea.

According to the team, this study provides an early framework for examining how CBD might help address health and behavior problems in older dogs, as well as in humans with similar concerns. "There are many similarities in how CBD can benefit dogs and humans medically," Leung concluded.