Cognitive decline

Canine cognitive dysfunction is the dog's version of dementia. It is common and it is under-diagnosed: a survey of older companion dogs estimated that 14 percent showed the syndrome while fewer than 2 percent had been diagnosed¹. The odds rise steeply with age. One owner survey found at least one sign in 28 percent of dogs aged eleven to twelve and in 68 percent of dogs aged fifteen to sixteen². In the Dog Aging Project's 15,000 dogs, the odds rose by half with each extra year, and inactive dogs had over six times the odds of very active dogs of the same age and health³.

Vets screen with the DISHAA list: Disorientation, changes in social Interaction, Sleep-wake disturbance, House soiling, changes in Activity, and Anxiety⁴. Standing in corners, getting stuck behind furniture, not greeting you, pacing at night, forgetting house training, and new clinginess or fear are the everyday forms⁴⁵.

Nothing reverses it, but progression can be slowed. AAHA's senior guidelines list a diet rich in antioxidants and medium-chain triglycerides, environmental enrichment, and the drug selegiline, which is approved for the condition in dogs⁶⁷. In aged beagles, enrichment plus a fortified diet preserved learning over two years⁸. Tell the vet early: the signs overlap with pain, hearing loss and other illness that can be treated.

This is general information, not a diagnosis. Your vet knows your dog.

Sources

1. Under diagnosis of canine cognitive dysfunction: a cross-sectional survey of older companion dogs (Salvin HE et al.). The Veterinary Journal 184(3):277-281, 2010 (peer reviewed). Accessed 2026-09-22.
2. Prevalence of behavioral changes associated with age-related cognitive impairment in dogs (Neilson JC et al.). Journal of the American Veterinary Medical Association 218(11):1787-1791, 2001 (peer reviewed). Accessed 2026-09-22.
3. Evaluation of cognitive function in the Dog Aging Project: associations with baseline canine characteristics (Yarborough S et al.). Scientific Reports 12, 2022 (peer reviewed). Accessed 2026-09-22.
4. Cognitive dysfunction syndrome: a disease of canine and feline brain aging (Landsberg GM, Nichol J, Araujo JA). Veterinary Clinics of North America: Small Animal Practice 42(4):749-768, 2012 (peer reviewed). Accessed 2026-09-22.
5. Canine cognitive dysfunction: pathophysiology, diagnosis, and treatment (Dewey CW et al.). Veterinary Clinics of North America: Small Animal Practice 49(3):477-499, 2019 (peer reviewed). Accessed 2026-09-22.
6. 2023 AAHA Senior Care Guidelines: Managing Cognitive Dysfunction and Behavioral Anxiety. American Animal Hospital Association. Accessed 2026-09-22.
7. Behavior Problems of Dogs (cognitive dysfunction syndrome section). Merck Veterinary Manual. Accessed 2026-09-22.
8. Learning ability in aged beagle dogs is preserved by behavioral enrichment and dietary fortification: a two-year longitudinal study (Milgram NW et al.). Neurobiology of Aging 26(1):77-90, 2005 (peer reviewed). Accessed 2026-09-22.