Pleasure is widely viewed as an essential component of happiness: food excites the reward system, stimulating dopamine to ignite desire and anticipation, and then when we eat, opiates and cannabinoids are released – basically, drugs made by our own brains.
Some patients even report a pleasurable equivalent of "jogger's high", caused by the release of the brain's own pain-killing opiates called endorphins.
In an interview last week Jane Maxwell, an epidemiologist at the University of Texas, told me that she worries that as police start to shut down the pill mills, some people who have developed addictions to synthetic opioids may turn to real opiates, like heroin.
He developed synthetic juvenile hormone in insects, preventing them becoming adults, for non-toxic control of mosquitoes and fleas, developed corticosteroids for inflammation steroids had been a passion since the 1940s and devised a way of detecting opiates in urine, used by the army in Vietnam.
And the most deadly drugs—opiates such as heroin and, increasingly, illicitly-acquired methadone are not clubbing drugs.
And the weight of the other substances with which a dealer mixes his drugs is included in the total, so 10 grams of opiates mixed with 190 grams of flour gets you 15 years.Ms Collette underwent drug treatment before being locked up, and is now clean.
These are natural opiates that are involved in the suppression of pain, and this anticipation-driven response is believed to be responsible for the placebo effect the fact that merely believing a treatment will help means that it actually does help.
Since 1998, when the UN held an event entitled "A drug-free world: we can do it", consumption of cannabis (marijuana) and cocaine has risen by about 50%; for opiates, it has more than trebled.
It says there is no shortage of such drugs; the problem is poor distribution and many countries' lack of medical experience in using opiates.
Last year, opium production in Afghanistan generated up to $1.2 billion, or almost 20% of GDP.Neighbours also profited from the windfall: criminal groups from Central Asia, says the UN, made profits of $2.2 billion from the trafficking of opiates in 2002, equivalent to 7% of the region's GDP.
The country's trade representative was caught with 24kg of heroin.But Tajikistan's president, Mr Rakhmonov, appears committed to fighting the plague, and seizures of opiates are on the rise, reflecting not only increased traffic but also better law enforcement.
