The latest must-have Hollywood accessory is a small, white, ovoid tablet. It will relax you, and make you happy. Not dangerously, wildly happy; just really quite content. It makes life "sweet and smooth", but you can still get to work on it, and do your job just fine.
The pill is Vicodin, an unglamorous enough sounding painkiller, and you can get it from your doctor if you live in the States. And it's so big right now that rap singer Eminem has one tattooed on his arm. Indeed "Vike", as it's known, is, according to singer and actress Courtney Love (herself no stranger to mind-altering substances), "the new LSD - lead singer's drug".
They'll tell you it's not addictive, provided you follow your doctor's orders. According to Laura Bradbard, from America's Food and Drug Administration, Vicodin is prescribed for moderate to severe pain, after, say, surgery. "Like all narcotic pain relievers," she says, it does have "addiction potential". But if you follow your doctor's instructions, the right dosage of Vicodin is, she says, harmless.
Sadly, as rather publicly demonstrated by the likes of Melanie Griffith and Friends star Matthew Perry, many, many people do not follow their doctor's orders. Perry was first prescribed Vicodin, which is closely related to heroin, after he hurt himself in a snowmobile accident. Griffith says she took the drug because of a sore neck. Both ended up in rehab. Clearly then, Vikes are extremely addictive for some people. You hear stories about people gobbling up to 80, which can't be good. It has become such an abused drug that places like the Waismann Institute in Beverly Hills advertise special Vicodin detox programmes.
Unlike with heroin and cocaine, there isn't such a stigma attached to getting hooked on prescription drugs, however. While everyone tuts and sniffs at Robert Downey Jr's junkie antics, the plight of Griffith or Perry is cast in a rather more innocent "how did it happen to me?" light. Griffith, uniquely, was happy to share her experience of detox with her fans on her website, describing how she "detoxed like a junkie".
And Griffith and Perry are certainly not alone in their addiction to a prescription drug. In the US, the National Institute on Drug Abuse estimates that in 1999, 4m people - about 2% of the US population over the age of 12 - were abusing prescription drugs. In Britain it is estimated that about a third of the adult population are now taking anti-depressants, painkillers or sleeping pills in some form.
The specifics of this kind of drug abuse are understandably elusive. "It's difficult to ascertain the level of addiction to drugs like these," says Adam Frankland, from Drug Link Hammersmith and Fulham, "but with any mind-altering drug there is going to be a street market."
While Vicodin is not available in Britain (unless you manage to order it over the net, or have a fancy private doctor, of course), other prescription drugs can be just as addictive. Here, benzodiazepines, the group of drugs that include valium and temazepam (sedatives or tranquilizers) is a bigger problem than painkillers. It is now illegal to be in possession of temazepam without a valid prescription, and GPs are not allowed to prescribe it in its gel-capsule form because addicts can melt it down and inject it straight into the bloodstream.
But it is the gentle high you get from opiate painkillers that has made Vicodin so trendy in pill-popping circles across the pond. Dr Kamran Ahmad, pain relief specialist at the University of Washington Medical Center, says: "Vicodin is a mixture of hydrocodone and paracetamol. The hydrocodone, like morphine, is what is known as an opioid [an opiate-type drug produced naturally in the brain]. Opioids attach themselves to specific proteins in the brain and spinal cord called opioid receptors. Basically, by attaching to these, the drugs block the transmission of pain messages to the brain."
This feels good because, Ahmad says, "in doing this, the drugs can also affect regions of the brain that control what we perceive as pleasure". But it's not all fun and games. "They can also make you nauseated, drowsy, dizzy, constipated and, depending upon the amount you've taken, they can slow your breathing down - sometimes dangerously." Perry, for one, suffered an acute attack of pancreatitis and lost a great deal of weight when he was hooked on Vikes.
Opioids can also interact dangerously with other drugs. "If you take them with alcohol, antihistamines, barbiturates, or benzodiazepines you get an increased sedative effect," says Ahmad. "The worst case scenario is that it slows your breathing so much that you stop altogether."
If you already have addiction "issues", as they say in California, drugs such as Vicodin can be just too tempting. Richard Rogg director of Promises, the Malibu rehab center where Ben Affleck and Robert Downey Jr recently had treatment, says Vicodin is so readily available in the States that it's hard for addicts to say no. "A lot of people who have been sober a long time fall into it because Vicodin is so easy to get hold of," says Rogg.
This is because "a lot of doctors are prescribing Vicodin without understanding that you should not give it to an addict". And canny addicts, Rogg adds, "can be working five different doctors at once". If you're really desperate you can even drive over the border to Mexico and get a bag of Vicodin from a pharmacy for $4 a pill.
But it's not just addictive personalities who should be extremely cautions with this kind of medication. "A significant proportion of people who have been prescribed the opiate painkillers become dependent on them without knowing it,"says Frankland. "Addiction usually begins as a psychological dependency. Often you don't realise it has become a physical dependency until your source runs out."
It's no wonder, then, that the rehab business is very big business indeed in Hollywood. At Promises, which costs around £20,000 a month, it takes about a week to kick Vicodin. It probably takes a lot longer if you are doing it on your own. But whether you're eating gourmet cold turkey or just feeling like one, the withdrawal symptoms will be the same: restlessness, muscle and bone pain, insomnia, diarrhea, vomiting, cold flashes, goose bumps and involuntary leg movements. Just like coming off heroin, in fact.