British pet owners have been feeding anti-depressants to their dogs and cats, vets have warned.
As people's lives are busier than ever, pets are increasingly left alone at home resulting in behavioural conditions.
A recent report by the People's Dispensary for Sick Animals (PDSA) found that more than a quarter of dog owners leave their pet alone in the house for five hours or more during a weekday and that 250,000 dogs are never walked, leading to serious behavioural problems.
Long periods of separation from their owners can lead to hyperactivity, obsessive-compulsive behaviour and anxiety, linked to being cooped up in an empty house for hours at a time.
Now, many pet owners are turning to drugs in a bid to counter the animal's sense of loneliness, either feeding them their own supplies of human antidepressants, or obtaining a prescription from their vet for animal-specific medication.
Andrew Knight, professor of animal welfare and ethics at the University of Winchester, told the Sunday Telegraph: "The number of behavioural problems in dogs and cats, and even other pets, such as birds, seen by veterinarians is huge.
'We're constantly seeing animals that are aggressive, unduly fearful, or barely under control when they visit, although my colleagues and I do our best to put them at ease with gentle handling and tasty treats.
"Instead of attempting to calm or even sedate our stressed pets with pharmaceuticals, it's about time we started giving our pets the care and attention they really deserve. Only then might we truly be eligible to call ourselves a nation of animal lovers."
Several licensed anti-depressants specifically for animals are available, including Clomipramine, Selegiline and Reconcile which work in a similar way to the human anti-depressant fluoxetine.
Dr Knight said that drugs are not a solution and that dogs need love and attention. "Dogs need to be walked, every day, yet too many are left at home with little to do while owners go to work," he explained.
"It's hardly surprising many resort to barking and demolishing the furniture, in their desperation for attention and stimulation. Such problems are widespread within our pet population, and constitute a major, under-recognised animal welfare problem."
The British Small Animal Veterinary Association said that medication should only be used after diagnosis by a vet.