West Valley, Phoenix, Arizona, is one of the worst-hit areas for meth addiction in the United States. The drug is manufactured in Mexico, then transported across the US on the interstate highway that comes right through our area. Meth is incredibly cheap here. Sometimes, dealers will give it away just to get kids interested. In 2004, I was assistant principal at an elementary school in the area. We caught one child in possession of meth, and through a series of conversations it became clear that other students were also using the drug. We were shocked to learn that one child had first used meth when he was just six years old, others when they were just seven or eight.

Because we hadn’t caught children in possession, there was no legal issue and no question of exclusions. If we’d wanted to, we could have just pretended that there wasn’t a problem. But we decided that if we wanted to be a team player in the community, we had to take action. We opened up a separate classroom, and established a school-based drug recovery centre.

The idea was to create a place where children could continue to receive an education, but with all the necessary support and counselling on hand. That first year we had 14 meth users in the class.

The project has evolved since then. We’re now a separate school and we take children from all across the area who have any kind of substance addiction.

Meth still accounts for most of the problems, but cocaine is on the rise too, because the price has dropped dramatically.

Our children are seventh and eighth graders - aged 12 to14 - and are here on a voluntary basis. Most have no discipline history. They aren’t here because they have been excluded from another school, but because they recognise they need help.

The school day is fairly normal. But whereas children of this age would usually have different teachers for each subject, here they have just one teacher. This means that the bond of trust between the children and their teacher is much greater. That’s very important.

We are trying to give children the necessary life skills to help them avoid substance abuse, which means exploring the underlying issues that have led them to use drugs. They have group therapy two days a week, and there is also individual and family counselling. We try to make our students aware of the support that is available to them so that when they move up to ninth grade and go off to high school, they are able to access outside services.

It’s not easy to identify children who use meth, because there are no stereotypes. The drug is used by boys and girls of all ages, from all socio-economic backgrounds. As a teacher, you think you will spot a drug addict because their grades will suffer or they will seem unhappy. But that isn’t always the case with meth. In fact, grades can go up when a child first starts using. After all, they’re not sleeping and they’re feeling good. With meth it takes quite a long time for the negative effects to outweigh the positive ones.

The important thing is to show that you’re a caring person. Most users reach a point where they realise they need help. If a student trusts you, they will have someone to turn to. If not, they may have nobody. It isn’t helpful to confront them, by asking them outright if they use drugs. Once you accuse, the bond of trust is broken. All you can do is to keep letting them know that you are there for them.

Meth is a truly horrible drug - the worst I’ve seen. You are addicted the first time you use it, and you will spend the rest of your life fighting that addiction. You’re forever trying to recapture that first high, but won’t ever achieve it. It changes the chemical balance of your brain, causing you to see and hear things. You lose weight, and develop open sores. It affects your ability to feel emotion and makes you less of a human being.

But it’s not a hopeless situation. We believe that we make a real difference to the children who come here. Of course, we are realists and we know that some students will go back to meth when they leave. But out of our first group of 14 leavers, 13 are still in high school, with just one dropping out. A couple have admitted going back to meth and some others are using marijuana. But, overall, the picture is very encouraging. None of the students who left has been in legal trouble, which suggests they are coping well. Our success rate is certainly well above the 3 to 10 per cent which most experts say is possible. We would put it at over 50 per cent - and that’s a conservative estimate. It shows our approach is working.

Amy Perhamus is principal at Calderwood alternative school. She was talking to Steven Hastings