Ask a group of 13-year-olds if they know what cancer is, and they'll most likely provide you with a resounding "yes." Ask them to explain bipolar disorder, however, and you'll probably receive a jumbled answer -- or a puzzled stare.

Around 42.5 million American adults suffer from some mental illness each year, according to data compiled by the Substance Abuse and Mental Health Services Administration. But despite the prevalence of conditions such as depression, bipolar and schizophrenia, many children and teenagers know little about these real -- and treatable -- diseases.

It's important to correctly educate children and teenagers about mental illness, health professionals say. It helps dispel misconceptions and stigma, and it provides them with the understanding and resources they need if they -- or someone they know -- struggles with a psychiatric disorder.

Curious how to tackle the topic with your own kids? Here are some tips:

Know Your Facts

To successfully teach a kid or teenager about mental illness, you first have to teach yourself, says Judy Davis, author of "Those People," a book inspired by the years she spent as a chaplain in a psychiatric ward, helping families and patients deal with mental illness.

Don't know the symptoms of depression? Find a book written by an authoritative mental health professional and learn them. Stymied by the difference between schizoaffective disorder and schizophrenia? Speak with a physician who can explain the distinction. "You can't just make a blanket statement and say that [all mental illnesses] are the same and they should all be treated the same. They differ a lot, and [diseases like] schizophrenia and depression are pretty far apart," Davis says. "Parents should read up on them so they'll understand what they're talking about."

It's also important for parents to understand that they don't need to have all the answers right away. "It's OK to say [to your child], 'I'm not sure, but I can try to figure it out," says Cathryn Galanter, director of the Child and Adolescent Psychiatry Fellowship Program at SUNY Downstate/Kings County Hospital Center.

Dispel Common Myths

Most kids cobble together a working knowledge of mental health topics through bits and pieces gleaned from their peers, parents and the media, says Kenya Sesay of the National Alliance on Mental Illness, a nationwide grassroots nonprofit that provides treatment, support and advocacy for the mentally ill. However, Sesay says, this body of information is often inaccurate.

Kids "know more about the stereotypes [for mental illness] than what it actually is," says Sesay, who serves as the youth program director of NAMI's Montgomery County, Maryland, chapter. "They don't really know the symptoms. They don't really know what the person goes through."

There are many misconceptions about mental illness: that all people with mental illness are violent; that psychiatric diseases are moral or character flaws; and that those who have them can't live normal lives. In reality, the majority are nonviolent, and coping methods ranging from medication and therapy to exercise can help individuals stay healthy and productive. The main point that Sesay and NAMI try to make to kids? Mental illness "has nothing to do with you. It doesn't make you any less of a person."

Find a Teaching Opportunity

"It can be helpful to bring [mental illness] up in context -- for example, if your child knows that someone is having difficulties with their mood or behavior and has questions about it," Galanter says. "As mental illness becomes less stigmatized, we are also hearing more about people in the news with mental illness. This can be a good opportunity to start a discussion. As with any more serious discussion, choosing a time when you and your child can focus is helpful, such as over a meal, in a long car ride or during a quiet time at home."

But you don't necessarily need to use a news peg or a media moment as an excuse to raise the subject, Sesay says. A discussion about mental illness, she emphasizes, is "a conversation that anyone can have. It shouldn't be like a 'birds and the bees' type of talk."

Tailor Your Language to Different Age Groups

"When speaking to your child or adolescent about mental illness, it's important to keep in mind their age and developmental level," Galanter says. "For preschool children, keep it simple. With this age, you may only need to have these discussions if someone they know is affected. School-aged children may have more questions. With this age, it's helpful to be clear, simple and direct, and to follow their lead in terms of how much information you give them."

With teenagers, Sesay says, you can be more specific -- especially because their age group faces a high risk of depression and suicide. Teaching them the names and traits of various illnesses gives them the knowledge and coping skills they need if they, or someone they know, experiences a psychiatric disorder firsthand. That way, they can seek support from a teacher, a parent or a counselor.

Tell Them They Have a Safety Net

Since mental illness is fairly common -- with as many as 61 percent of people experiencing a well-specified psychiatric disorder by age 21, according to Galanter -- children may first learn about it through personal experience. In this case, they're usually advised to confide in a trusted adult. But a fear of stigma often keeps them from coming forward. "A lot of the time, [kids] believe if they have a mental illness, nobody should know," Sesay says. "They think people will look at them differently."

Let them know that's not the case. Mental illnesses are "like other medical illnesses. It's not your fault," Galanter stresses. "They are diagnosable and treatable. Help is available."