Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.
Animal companionship may reduce agitation in people with dementia and other conditions through measurable biological changes—primarily the release of calming hormones like oxytocin and dopamine, combined with the grounding effect of caring for another living being. When someone with dementia interacts with a dog, cat, or even aquarium fish, their brain activates reward pathways and stress-reduction systems that naturally counteract the emotional dysregulation associated with agitation. This isn’t speculation: clinical research has documented that about 57% of peer-reviewed studies on pet-assisted therapy found statistically significant reductions in agitation and delirium among hospitalized patients with cognitive impairment.
Consider the case of Margaret, a nursing home resident with mid-stage Alzheimer’s who had begun pacing and shouting during afternoons—a common phenomenon called sundowning. After a trained therapy dog visited twice weekly, her care team noticed she was calmer during those afternoon windows, engaged in petting and talking to the animal rather than expressing agitation. This isn’t magic; it’s neuroscience. Understanding how and why animals have this effect can help families and caregivers make informed decisions about whether animal companionship is right for their situation.
Table of Contents
- What Happens in the Brain and Body When We Interact with Animals?
- What Does the Research Actually Show About Agitation Reduction?
- Do Animals Help Specifically with Dementia-Related Agitation?
- How Do You Choose the Right Animal Companion for Someone with Dementia?
- When Animal Companionship May Not Work or Could Backfire
- Beyond Agitation Reduction: The Broader Role of Animal Companionship
- The Evolving Role of Animal-Assisted Therapy in Dementia Care
- Conclusion
What Happens in the Brain and Body When We Interact with Animals?
The mechanism behind animal companionship’s calming effect is rooted in physiology. Petting an animal triggers the release of oxytocin—sometimes called the “love hormone”—alongside dopamine and endorphins. At the same time, cortisol (the primary stress hormone) decreases. This cocktail of neurochemical changes explains why simply sitting with a dog for ten minutes can feel restorative.
The effect is immediate and measurable: studies using heart rate monitors and cortisol tests show that blood pressure drops and stress markers improve within minutes of animal contact. For people with dementia, this becomes particularly important because agitation often stems from anxiety and confusion. The brain’s ability to regulate emotions is already compromised, so introducing a stimulus that triggers calming hormones—without requiring complex social interaction or verbal communication—can interrupt the agitation cycle. A person with advanced dementia might not remember your name, but their nervous system will still recognize and respond to the soothing rhythm of stroking a cat’s fur or playing with a dog. The hormonal shift is not dependent on memory or cognition; it happens at the physiological level.
What Does the Research Actually Show About Agitation Reduction?
Clinical evidence supporting animal-assisted therapy comes from rigorous studies, not anecdotes. A comprehensive review of pet-assisted therapy for hospitalized patients with neurocognitive impairment found that in 57% of the included studies (8 out of 14), patients exposed to pet therapy showed statistically significant reductions in agitation and delirium compared to control groups. This is a substantial finding, though it’s important to note that not every study showed positive outcomes—some found minimal or no effect. The variation likely depends on the type of animal, the patient’s prior relationship with animals, and the quality of the intervention.
Outside of acute hospital settings, meta-analyses of canine-assisted therapy with university students showed moderate reductions in stress and anxiety, and during the COVID-19 pandemic, elderly pet owners demonstrated significantly lower anxiety scores on validated psychological scales compared to non-pet owners. These aren’t small differences; they’re clinically meaningful improvements. However, it’s worth acknowledging a limitation: most robust research focuses on dogs, and less is known about the long-term effects of other animals, though fish and cats have shown promise in preliminary studies. The evidence is strong enough to warrant consideration, but not so overwhelming that every animal companion will work for every person.
Do Animals Help Specifically with Dementia-Related Agitation?
The research on dementia and animal-assisted therapy is particularly encouraging. In studies of geriatric patients with dementia and Alzheimer’s disease, dog-assisted activities were associated with reduced agitation and increased social interaction. One meta-analysis examining behavioral and psychological symptoms of dementia (often shortened to BPSD, which includes agitation, wandering, and mood disturbances) found that animal-assisted therapy groups showed significant improvements, especially in reducing depression and behavioral symptoms. Fish companionship, though less studied than dogs, was found to reduce agitation, increase food intake, and improve body mass index in dementia patients—suggesting that the animal doesn’t need to be cuddly or interactive to provide benefit.
This matters because dementia-related agitation is often difficult to manage pharmacologically without causing sedation or other side effects. A non-pharmaceutical intervention that addresses the underlying emotional dysregulation while simultaneously providing engagement and purpose is genuinely valuable. The limitation here is important: not every person with dementia will benefit equally. Those who are afraid of animals, have a history of allergies, or lack previous positive experiences with pets may not show the same calming response. Additionally, introducing a new animal requires resources—proper training, veterinary care, and ongoing supervision—which not all care facilities or families can provide.
How Do You Choose the Right Animal Companion for Someone with Dementia?
Dogs are the most researched and widely used animals in therapeutic settings, which makes sense: they’re responsive to human interaction, can be trained to handle behavioral challenges, and provide obvious affection. However, they require significant care, exercise, and management—which may be unrealistic for a person with advanced dementia or for a caregiver who is already stretched thin. In these situations, cats or fish may be more practical. Fish require minimal hands-on interaction but provide visual stimulation and a sense of routine (feeding schedules can provide structure). Cats offer tactile comfort with lower maintenance demands than dogs. When considering an animal, think about the person’s history.
Someone who spent decades with dogs will likely respond more positively to a dog than a person who never had pets. Consider also the person’s current abilities and fears. Someone with late-stage dementia who has become fearful of unfamiliar situations may be more distressed than soothed by a large, energetic dog. Size matters too: a small, calm dog or cat may be less overwhelming than a large breed. The comparison here is worth making explicit: a dog provides more interaction and companionship but demands more from caregivers; a fish provides visual routine and minimal care demands. Neither is universally “better”—it depends on the capacity and context of the care situation.
When Animal Companionship May Not Work or Could Backfire
Not every person will benefit from animal companionship, and pushing the issue can cause more harm than good. Some people with dementia develop agitation specifically around animals—either due to lifelong fear, or because their cognitive decline has made them misinterpret an animal’s behavior. A person who sees a dog’s playfulness as a threat, or who becomes obsessive about caring for a pet in ways that aren’t safe, may become more distressed rather than calmer. Additionally, if a family or facility introduces an animal without proper training or supervision, the animal may itself be mistreated (even unintentionally, as someone with dementia may handle a pet roughly) or the person may experience anxiety about harming the animal. There are also practical warnings to consider.
Animal companionship requires veterinary care, food, cleaning, and potential management of allergies or infections in vulnerable populations. If a facility or caregiver introduces an animal but then cannot sustain proper care, the experience may become negative—and removing the animal later can trigger additional grief and agitation in the person with dementia. Before pursuing this option, honestly assess whether the commitment is sustainable. The agitation reduction you hope for requires a consistent, well-cared-for animal and proper supervision. If that’s not possible, other interventions may be more appropriate.
Beyond Agitation Reduction: The Broader Role of Animal Companionship
Animal companionship often reduces more than just agitation; it can address multiple behavioral and emotional challenges simultaneously. Pet ownership has been shown to reduce stress, anxiety, depression, and loneliness across many populations, and these effects compound in people with dementia. A person who engages with an animal may also show improved appetite, better sleep, and more willingness to participate in daily activities. The animal provides what researchers call a “reason to get up in the morning”—a responsibility and a source of unconditional attention.
For some people with dementia, an animal can become a bridge to social connection. A dog visiting a memory care unit often draws attention from other residents and staff, creating opportunities for conversation and shared moments. This social stimulation, even in its simplest form, can reduce the isolation that often exacerbates agitation. One example: a man with mid-stage dementia who became withdrawn and angry began speaking more readily after a therapy cat was introduced. He attributed his improved mood not just to the cat itself, but to the conversations with staff and visitors who came to talk about the cat—the animal opened a door to interaction he’d been avoiding.
The Evolving Role of Animal-Assisted Therapy in Dementia Care
Animal-assisted therapy is increasingly recognized as a legitimate part of dementia care protocols, not a peripheral or “nice-to-have” addition. More memory care facilities are formalizing animal programs, training staff and volunteers, and measuring outcomes. Some facilities employ certified therapy animals, while others partner with local animal rescue organizations to bring animals into the environment. As the research base grows and care models improve, we’re likely to see more nuanced understanding of which animals work best for which populations and which conditions.
The future also includes the possibility of more diverse animal partnerships. While dogs dominate the research, emerging work on animals like guinea pigs, rabbits, and even horses suggests that therapeutic benefits may be broader than once thought. For people with dementia in particular, personalization will likely become the standard: rather than assuming all residents should have the same animal, care plans could be tailored to individual history, temperament, and response. This approach requires more resources and training, but the potential to reduce agitation and improve quality of life—without additional medication—makes it worth pursuing.
Conclusion
Animal companionship may reduce agitation in people with dementia through measurable changes in brain chemistry and stress hormones, supported by clinical evidence showing that about 57% of research studies documented significant improvements in agitation and delirium. The effect is not universal—it depends on the person’s history with animals, the type and quality of the animal-human relationship, and the consistency of care. When the conditions are right, animal companionship can address not just agitation but underlying emotional needs for connection, routine, and purpose.
If you’re considering animal companionship for someone with dementia, start by honestly assessing the person’s history with animals and your capacity to provide ongoing, quality care. Consider the practical demands of different animals and match them to your situation. Work with the care team to establish clear goals and monitor outcomes. When approached thoughtfully, animal companionship can be a meaningful, evidence-based strategy to reduce agitation and improve quality of life—complementing, not replacing, other medical and behavioral approaches.
