Back in the day – before Paris Hilton carried a pooch in her handbag, before professional dog-walking was a serious career, and before "doggy day-care" even existed – the most popular cure for an unhappy canine was, as the nursery rhyme goes, to give the dog a bone.
How times have changed. A surge in the popularity of household animals, coupled with the licensing of several new veterinary drugs, is seeing thousands of American dog owners replace comforting marrow-bones with a chemically enhanced modern alternative: Pet Prozac.
Lifestyle drugs to treat troubled canines for depression, anxiety, bad behaviour and even obesity are being launched by pharmaceutical firms anxious to cash-in on the nation's booming love affair with man's best friend. Most of the new pills are almost identical to those popped by humans – and some are proving very controversial indeed.
This month, the American Veterinary Medical Association's (AVMA) annual convention in New Orleans, attended by more than 10,000 of the country's leading vets, saw a heated debate about the doggie anti-depressants Clomicalm and Reconcile, and a product called Slentrol – the world's first canine anti-obesity pill.
In a country where fawning-but-influential celebrities treat pets like furry child replacements, campaigners are worried by developments that further "humanise" domestic creatures, saying they will have a negative impact on animal welfare. When Reconcile, which (apart from a strong taste of beef) is virtually identical to Prozac, was officially licensed in the United States in May last year, the RSPCA issued a critical press release saying it would create an entire generation of "pill-popping pets". Behaviour-altering drugs encourage animal owners to neglect traditional training techniques, it said, in the mistaken belief that they can turn to a miracle medicine if things go wrong.
Pet endorsements from trend-setting film stars already mean that far too many dogs are ending-up in unsuitable homes, where they receive insufficient care and training and often end up suffering from psychological problems.
The Kennel Club blamed Jessica Alba this year for a 220 per cent rise in pug registrations, and said Scarlett Johansson was partly to blame for a doubling in the number of pet chihuahuas. The trend towards miniature dogs is expected to get worse this summer, with the release of a Disney film called Beverly Hills Chihuahua.
Drugs are increasingly seen as a "quick fix" to psychological problems such as "separation anxiety", which now affects 14 per cent of America's dogs. As a result, pet pharmaceuticals represent a lucrative future market for manufacturers. Aside from consumer electronics, domestic pet care is the fastest-growing retail market in the US, up from $11.5bn (£5.8bn) in 2003 to $49bn this year. Major drug firms such as Pfizer are seeing rising demand and their profits from animal medicine increasing by roughly 25 per cent a year. Some have even created their own "Companion Animal" division.
Most new products are aimed at combating "separation anxiety", a condition that typically sees animals become highly agitated when their owner leaves the house. If left alone, they bark, drool, and often defecate, despite having been house-trained. In the company of other dogs, a sufferer will also often behave in an aggressive manner.
"There are animals out there who are literally worrying themselves to death," said the former AVMA president Dr Bonnie Beaver. "As a vet, if the situation is appropriate, then I will prescribe a pill.
"If you have a dog that's constantly hiding under chairs and tables, and it's impossible to even take him to training class, these drugs can at least make it possible for them to learn."
Dr Beaver said that a range of medicines developed for humans can be used on mentally unstable canines. "There's a generic Prozac called Fluoxetine, which can be used if the label version is prohibitively expensive," she said. "Valium is often used to calm down dogs who are having seizures, but you can also use it to help a dog who is scared to death by, say, going in a car. Xanax is used on dogs frightened of thunderstorms."
In the glitzy world of Hollywood dog trainers, many experts now find themselves working with pooches who are wide-eyed, thanks to anti-depressants. Caryl Wolff, a behaviourist who runs the Doggie Manners school in the upmarket suburb of Brentwood, said that increasing numbers of his animal clients have been prescribed psychiatric medication by vets.
"I have a patient now who is on Clomicalm," she said. "It's a recently adopted Malinois mix. When the owner is around, it is affectionate. But as soon as they prepare to leave the house it starts drooling. Then it becomes agitated and barks. While they're away, it will salivate all over the property; it pees and poops, barks and howls and whines."
Although Ms Wolff would rather treat dogs with a mixture of new-age techniques – from aromatherapy to acupressure massages to soothing music – she has no objection to the use of drugs to treat severe conditions. "When you see how these owners are torn apart and see how the dogs are torn apart by separation anxiety, it's difficult not to think that if something can help, and it's a drug, then why not."
However, others, like the television dog trainer David Reinecker, have reservations. Mr Reinecker – who has been hired to look after the welfare of several Hollywood pooches, including Sammy and Spunky, the problem labradors of Arnold Schwarzenegger – fears that psychiatric drugs are increasingly being used as a first resort, rather than a last. "Very, very rarely, once or twice a year, I will have a case where there's nothing that's going to help except drugs but it's a very rare condition," he said. "I would say that 95 per cent of the time you should cure a dog's mental problems without drugs."
Mr Reinecker says he gets a lot of clients coming to him after feeding their pets Clomicalm or Prozac or Reconcile straight off, and then finding that the drugs don't work for them,He prefers to perform what he calls "magic" on a client's dog, which involves a form of "dog-whispering" to diagnose what's wrong. Then he will advise treatments such as aromatherapy or changing an animal's diet to modify behaviour. He's currently spending three days a week at Arnie's home, helping their new puppy, Gustav, who is named after the actor-turned-politician's father.
The most influential member of the anti-drug lobby is the vet Dr Ian Dunbar, who founded the Sirius Dog Training empire, with branches across California. He believes that almost all forms of psychiatric drugs are unnecessary. "If all puppy owners knew how easy and how much fun it is to raise and train a puppy, we wouldn't need drugs, and we wouldn't need to retrain them as adults," he said.
"People seem to have the impression that all they have to do is to buy the perfect puppy and it will magically turn into the perfect dog. Then they come to me and say, 'When I'm out of the house all day it barks or chews things'. My answer to that is: 'What did you expect it to do? Needlework?'"
"Drug companies are in the business of making money, they have a huge advertising budget and they target pet owners directly. I actually feel sorry for the vets because of this. It means that people come to them having seen the adverts saying 'I want a pill' because they think it will be quick and easy. Mostly it isn't."
Other experts worry that the drugs, which are still relatively new, may end up causing physical or mental dependency among the animals that take them. "I've not seen a physical dependency like you'd get with nicotine or caffeine, but that is to a certain extent an open question," said the Beverly Hills animal psychiatrist Richard Polsky. "There haven't been enough cases for long enough for us to be sure."
Perhaps those bearing the greatest burden,though, will be the pet owners who have to fork out an extra several hundred dollars a month to keep their pooches in happy pills. Indeed, such is the demand for cheaper versions that many Californians are crossing the border into Mexico to secure cheap veterinary drugs from their relatively unregulated market.
In some instances, the wheel has come full circle: as well as animals using human drugs, humans are using the trip to secure animal drugs for home use. A recent Reuters report revealed that euthanasia campaigners are even coming home with liquid pentobarbital, commonly used to put cats and dogs to sleep, to help with assisted suicides.
The canine must-have medicine cabinet
Clomicalm About 14 per cent of American dogs suffer from "separation anxiety" – a fear of being left alone – and Clomicalm claims to deal with the barking and "destructive behaviour". Its human equivalent is Anafranil, an anti-depressant.
Reconcile The chewable anti-depressant is a beef-flavoured Prozac. When used with a training plan, it is supposed to relieve separation anxiety. More than half the dogs using it suffered from short-term side effects such as lethargy and depression.
Slentrol The world's first canine anti-obesity pill. The makers say it works in the small intestine by preventing all the fat from being absorbed. And voilá, your dog will be the envy of all its canine counterparts.
Anipryl It's not just humans who are living longer, but dogs are too – with the average age of an American dog now at 13. This new drug, also known as L-deprenyl, the identical drug prescribed to people with Parkinson's and Alzheimer's, is used for Cushing's Disease and Canine Cognitive Dysfunction.
It is available on pet prescription to treat anxiety. It has been used to calm canine irritable bowel syndrome as well as "thunderstorm phobia".
By Miranda Bryant