10. Mixed-Breed Rescue Dogs
While not a purebred entity, mixed-breed dogs consistently register elevated rates of separation-related distress. The 2020 Scientific Reports study highlighted mixed breeds alongside Wheaten Terriers as having the highest clinical prevalence of separation anxiety. Research from the Journal of the American Veterinary Medical Association (JAVMA) demonstrated that shelter and rescue dogs accounted for 41.1% of separation anxiety cases compared to 29.6% in control groups, making rescue dogs 1.66 times more likely to develop separation distress due to past attachment disruptions and shelter stress.