Equilibrium

There is a film starring Christian Bale called Equilibrium, it works on the premise that after a world war, the victors control the population by getting them to take a drug to dampen emotions allowing them to become fully functioning and efficient members of society. Of course this also removes all interest in art and beauty leaving a soulless society controlled by the state and their quasi religious paramilitary arm.

Synopsis.

In the future, war has been eliminated and the most dangerous contraband is human emotion. Feelings and all things that evoke them including art, music and poetry, are forbidden, and their possession punishable by death. Cleric Preston is the top ranking Government official, a veritable killing machine, who along with his partner is encouraged to hunt down and kill those who resist the rules.

Pretty good film if you enjoy that sort of thing but a bit unlikely you'd think...
Sadly it appears you might think wrong.

Daily Mail.

Forget the age-old remedies of yoga, meditation or popping pills. Relieving chronic stress could soon be as simple as having an injection, according to scientists.
Academics say they are close to developing the first vaccine for stress - a single jab that would help us relax without slowing down.
After 30 years of research into cures for stress, Dr Robert Sapolsky, professor of neuroscience at Stanford University in California, believes it is possible to alter brain chemistry to create a state of 'focused calm'.
After early setbacks, the Stanford team has adapted a herpes virus to carry engineered 'neuroprotective' genes deep into the brain to neutralise the rogue hormones before they can cause damage. The virus is now shown to work on rats.
'To be honest, I'm still amazed that it works,' Professor Sapolsky told Wired magazine recently.
He warned that human trials are years away, but added: 'We have proved that it's possible. We can reduce the neural damage caused by stress.'

People deal with stress in all sorts of different ways, legal and/or otherwise. Tobacco, alcohol, exercise, various legal and illegal chemicals etc. However as the "Righteous" have moved heaven and earth to try and restrict these means  to the proles (as they see us) for "our own good" or more likely for to control us and get our cash off us the levels of violence in England have increased. People are no longer productive, for some it's easier to just live off the state rather than seek gainful employment and in the eyes of the "Righteous" these people need to be controlled. Now they have their means, one little injection and you have Mr/Ms docile on their hands, uncomplaining, unable to resist, unable to get angry at the intolerable intrusions of the state on their lives and freedoms, the perfect slaves happy to let an elite run things their way for themselves. No inconvenient elections, no popular uprisings, just docile sheeple, happy to do whatever is asked, the perfect tool for the ultimate dystopia.

What could possibly go wrong...

Update, Leg Iron and Trooper Thompson have their own takes on this, worth reading.