A team of Spanish researchers have released the first study that provides data on animal hoarding in Europe.

Animal hoarding, typically characterized as accumulating more than the typical number of domestic pets, can be characterized as a symptom of mental illness. Yet there is little research that provides data on this disorder, despite the negative effect that animal hoarding can have on the health of both the animals and the hoarders themselves.

Paula Calvo, an expert on anxiety, affective disorders and schizophrenia with the Hospital del Mar Research Institute in Barcelona, notes that hoarders are poorly understood and their behavior has a direct effect on public health. She said the new research will open the door to a path that will both educate the public and provide opportunities for treating mental illness.

"This is the first step towards public recognition of this disorder, a disorder that constitutes a growing concern for government as it is becoming a serious problem for public health. There are still no standardized action protocols for intervention in these cases," she said in a statement.

Using data from official records taken between 2002 and 2011, Calvo investigated 24 cases of hoarding in Spain. The cases involved 1,218 dogs and cats and 27 hoarders. The average number of animals per case was 50, with the most common animal being dogs.

The Human Society of the United States defines animal hoarding as keeping more than the typical number of companion animals. Animal hoarders are unable to provide minimum nutrition and sanitation standards for their animals, and this neglect often results in the animals' starvation, illness and even death.

"Although what causes animal hoarding is still poorly understood, there is a general consensus that animal hoarding is a symptom of psychological and neurological malfunctioning, which might involve dementia, obsessive-compulsive disorder, post-traumatic stress disorder, and attention-deficit hyperactivity disorder," the Humane Society states on its website. "Treatment is difficult and has a low rate of success. Typically a combination of cognitive-behavioral therapy and some type of psychopharmacological intervention is recommended."

Calvo said that currently, when cases of animal hoarding are discovered, the animals are removed, but there is not attention given to the hoarder. She contends that recognizing the presence of hoarding in our society is the first step in identifying and detecting cases early and dealing with them efficiently.

"Until now all existing research on the issue has been carried out in the US, Canada and Australia, but with this study it has been demonstrated for the first time that this mental disorder also occurs in Europe and with similar characteristics," the Hospital del Mar Research Institute said in a statement. "For the time being the data is not sufficient to know the percentage of the population which suffers from the disorder, nor to better understand the profile of those who hoard."

Calvo's study is published in the Journal of Animal Welfare.