Atila, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, falls asleep as it gets caressed by three patients at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Atila and Argi, trained therapeutic greyhounds used to treat patients with mental health issues and learning difficulties, run through the grounds at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Andres Garcia, 29, embraces Argi, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, as he relaxes at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Andres Garcia (L), 29, and Inaki Gorriz, 24, pet Atila, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, as their nurses and therapists look on at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Argi and Atila, trained therapeutic greyhounds used to treat patients with mental health issues and learning difficulties, enter their home at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Argi, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, wears a coat made by patients as he waits to get something to eat at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

David Villanueva, 44, reacts as he caresses Atila, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, in its bed at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Miren Martinez, 49, pets Atila, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Ramona Echeverria (L), 63, and Ion Albiz, 38, pet Atila, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Atila and Argi, trained therapeutic greyhounds used to treat patients with mental health issues and learning difficulties, try to get the attention of Ion Albiz, 38, at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

David Villanueva, 44, poses with Argi, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, at Benito Menni health facility in Elizondo, northern Spain. When asked what the greyhounds mean to him, he answered: "Care". REUTERS/Susana Vera 

Inaki Gorriz (L), 24, kisses social worker Irune Alchu, 31, as Andres Garcia (C), 29, walks hand in hand with nurse Andre Carricaburu, 24, while going for a walk with "Argi" and "Atila", trained therapeutic greyhounds used to treat patients with mental health issues and learning difficulties, at Benito Menni health facility in Elizondo, northern Spain. REUTERS/Susana Vera 

Andres Garcia, 29, poses with Argi, a trained therapeutic greyhound used to treat patients with mental health issues and learning difficulties, at Benito Menni health facility in Elizondo, northern Spain. When asked what the greyhounds mean to him, he answered: "Peace". REUTERS/Susana Vera