In 1948, Dr Maurice Rapport of the Cleveland Clinic discovered an important neurotransmitter and named it serotonin. When we don't have enough, it makes us grumpy.

We've been searching for the Holy Grail of happiness therapy for years, from St Johns Wort to Neuro Linguistic Programming...now it looks like a simple on/off transmitter could zap us all happy!

Researchers at the same Cleveland Clinic noticed that neural activity in parts of the brain correlate with symptoms of sadness and depression. and created a Deep Brain Stimulation (DBS) implant to jolt some sunshine into your life.

The implant consists of three components; the electrode placed in the brain, a generator implanted beneath the collarbone and a lead placed under the skin to connect them. Electric impulses are sent from the generator to the stimulator to interrupt neural activity at the target site. Because it is a permanent device, the DBS has been called the "brain pacemaker".

If you're thinking of getting one, like all things worth having, it ain't going to be easy. First, they bolt a titanium halo is bolted to your skull so that doctors can image your brain with minimal movement. Then they'll be drilling two coin-size holes into your skull, and inserting implants and wires through the holes. Mind you, there is good news - we don't have many pain receptors in the brain, so you'll only need a little local anaesthetic is needed and you can even stay awake while they make the holes in your head!

As the electric currents are activated, four out of six patients have report a feeling of a black cloud lifting, a desire to smile, faces become brighter and they become more alert and interested in their environment. I get the same when someone hands me a bar of Butterscoth Green and Black's but maybe that's a personal thing?

The changes are reversed when the current is switched off. After surgery, current levels can be controlled remotely by a doctor. So don't piss your doctor off or you could be ina really tricky situation! I can see it now, "Right, Mrs Smith. This is what you get for being rude to the receptionist..."

Apparently, electrical stimulation of the frontal cortex brings about a "striking and sustained remission" in people with clinical depression, whose symptoms had previously been resistant to medication, psychotherapy and electroconvulsive therapy.

Throughout the past 10 years the implant has been used to combat traumatic brain injuries and a host of movement disorders such as Parkinson's. But now Food and Drug Administration tests in the United States are under way to approve its use with clinically depressed patients.

So - I wonder if they will be licenced for PMT?