PETS at risk of self-harm are increasingly being prescribed anti-depressants because they cannot discuss problems in their lives with others, a leading veterinarian says.

Zoo and wildlife medicine specialist with the UK’s Royal College of Veterinary Surgeons, Romain Pizzi, told the Telegraph that more pets were being prescribed Prozac.

Tropical birds such as parrots seemed to have been the most affected by depression, Mr Pizzi told the newspaper.

But Mr Pizzi said anti-depressants were only used in the most extreme of cases.

“Firstly, we will change the environment of the animal and make sure it has more stimulation and toys,” Mr Pizzi told the newspaper.

"When we have ruled out underlying medical problems, we try to break the cycle by using Prozac… (which) is given to the parrots in liquid form.

"It doesn't cure all animals, but around two-thirds respond to the treatment. In a small number of cases things will go well until we wean them off Prozac and the problems return."

Mr Pizzi said the severity of some pet’s depression often put their lives at risk.

"Typically if people go out to work all day their parrot will get very bored and frustrated and eventually develop depression,” he said.

“Symptoms often include plucking out their feathers or self-harming, which is obviously very dangerous.

“When cockatoos in particular are depressed they can start to self-mutilate and peck their own legs to the bone."

Some of the world’s largest pharmaceutical companies have also recognised the need for anti-depressants for animals.

Last year, Eli Lilly released a chewable anti-depressant for dogs onto the US market.

The manufacturers even gave the “Reconcile” drug a beef flavour.

Pfizer has also created a diet drug for dogs, as well as motion-sickness medicine for all pets.