If pain killers are taken exactly as prescribed, they are safe and will rarely cause addiction. And yet addiction to prescription pain killers is growing. The most common medications that can cause this are opiods (sometimes called narcotics) and include morphine, codeine and others in the same group.

Research shows that every year, almost 2 million Americans use prescription opiod painkillers. In some communities, addiction to painkillers has now overtaken the use of cocaine and marijuana. 9% of the population admit to having used pain killers illegally.

Morphine is often used after surgery for the control and alleviation of severe pain. Codeine is more common and can deal with milder pain. Opiods work by attaching to proteins in the brain, spine and digestive tract. These proteins are called opiod receptors. When an opiod attaches to a receptor, they can change the way a person feels pain.

SO HOW DO PEOPLE GET ADDICTED TO THEM?

They can also affect how pleasure is experienced and this is why many opiods give a feeling of euphoria when they are taken.

People who become addicted start out by taking pain killers for longer than they should do, to get this initial euphoria. The problem is that if pain killers are used for a long time, the body can become tolerant to that medication. This means that higher and higher doses must be taken to get the same effect. It also means that the body has adjusted to operating normally with that level of pain killers, and so if the pain killers are stopped, or reduced, withdrawal symptoms can occur.

COLD TURKEY

Symptoms of drug withdrawal ae extremely unpleasant and can involve restlessness, pain in the bones and muscles, insomnia, diarhea, vomiting and involuntary leg movements. Withdrawal is called 'cold turkey' because another major symptom is cold flashes with goose bumps on the skin.

WHY DO PEOPLE NEED HELP TO QUIT - CAN'T THEY JUST STOP?

If these drugs are used for a long time, they will eventually change the brain in fundamental ways. They take over the normal pleasure and motivational systems of the brain - pushing the need for drugs up to the highest priority. The need for drugs therefore overrides all of the person's previous motivations, behaviours and drives. This is the domineering compulsion to find and use drugs, and what is called addiction.

Once addicted to drugs, people feign illness and visit different doctors to obtain prescriptions, buy drugs on the street, steal and lie to obtain their 'fix'. It is not a personality choice - it's a medical need or craving, generated by the affect that the chemical has imposed on the brain.

WHAT HAPPENS IN REHAB?

Celebrities seem to go into rehabilitation {rehab) with alarming frequency. Rehab is a place where people are medically supervised to come off their addiction, in an effort to reduce or avoid withdrawal symptoms. The addiction can be to pain killers, recreational drugs or alcohol.

The client is medically detoxified - which means that medications may be given to help them through the withdrawal phase. Detoxification is not a treatment for addiction - it simply removes the addictive substance from the person's system so that they can start thinking clearly again. Detox is usually followed by counselling and behavioural therapy to try and help the client to avoid returning to the addiction.

Celebrities and their alleged pain killer addictions:

* Kathleen Turner - pain killers and alcohol.

* Daniel Baldwin - pain killers originally for a back problem.

* Anna Nicole Smith - vicodin.

* Matthew Perry - vicodin.

* Jerry Lewis - allegedly went into rehab for prednisone addiction at the age of 77!