Obsessive-compulsive disorder is, it turns out, a cross-species problem. Canine compulsive disorder (CCD) includes "excessive tail chasing, light/shadow chasing, and flank-sucking." Basically, it's hand-scrubbing and nail-biting for four-legged creatures. Scientists at the University of Helsinki in Finland studied some provocative genetic and environmental influences for this behavior.

Dog lovers might be relieved to know that factors such as amount of exercise, time spent alone at home, and owner relationships didn't seem to influence CCD. The maternal bond, on the other hand, turned out to live up to its mighty reputation. Canines who were separated early from their mothers or neglected by them were more likely to have CCD.

CCD prevalence varied by breed. Males and females were equally afflicted, with one exception: Dogs who had been neutered tended to have less CCD overall, and that effect was most marked among females.

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