Methamphetamine, which can come in the form of a crystalline powder or rocklike chunks, is an addictive stimulant that can be smoked, snorted, injected or taken orally. Its street names include “ice,” “crystal,” “speed” and “tina.”

Signs that someone is using meth include:

. A change in sleep patterns and insomnia.

. Increased physical activity.

. Decreased appetite and weight loss.

. Aggression or a hostile and uncooperative attitude.

. Anxiety, paranoia.

. Hallucinations.

. Convulsions and tremors.

One expert in drug-use prevention suggests that parents learn about meth and other drugs and start discussing them with teens who are in the seventh and eighth grade.

That may seem early to some, but “I would prefer that my kids hear it from me, as well as what my expectations as a parent are,” says Karel Ares, executive director of Prevention First, an Illinois-based training and resource center that specializes in substance abuse prevention.

Ares says parents also need to ask their teens direct questions: “Become almost an investigative reporter. Ask, ‘Where are you going? And with whom? Tell me more about this party? Will there be adults there? Will there be alcohol there?'”

She also suggests getting to know the parents of a teenager’s friends.

“A lot of it’s just common sense,” Ares says. “But the stakes are substantially higher now, especially when you’re talking about these new drugs that weren’t around when we were growing up.”