Typical kid behavior or a mental-health problem? It can be hard to decide.
Mary Rose O'Leary has shepherded three children into adulthood, and she teaches art and music to middle school students.
Despite her extensive personal and professional experience with teens, the Eagle Rock, Calif., resident admits she's often perplexed by their behavior.
"Even if you have normal kids, you're constantly questioning, 'Is this normal?' " says O'Leary, 61.
Teenagers can be volatile and moody. They can test your patience, push your buttons and leave you questioning your sanity - and theirs.
I'm not being flip. Mental-health challenges are a serious - and growing - problem for teenagers: The proportion of 12-to-17-year-olds who said they had recently experienced symptoms of clinical depression increased by 37 percent in the decade ending in 2014, with 1 in 6 girls reporting an episode in the past year, according to a recent study.
And schizophrenia and other psychotic disorders often manifest themselves in adolescence. In fact, half of all mental-health conditions emerge by age 14, and three-quarters by 24, says Steven Adelsheim, director of the Stanford Center for Youth Mental Health and Wellbeing, part of the university's psychiatry department.
For parents, it's often hard to separate the warning signs of mental illness from typically erratic teenage behavior.
When O'Leary's son, Isaac, now 23, was a teen, he had two run-ins with police - once for hosting a wild party while his mom was away, and again when he and a friend climbed up on a roof and challenged each other to shoot BB guns.
O'Leary dismissed those incidents as teenage pranks. But she did start to worry when she was in the midst of divorce proceedings and noticed that Isaac started exhibiting some unusual behavior. He complained of stomachaches and racked up absences from school.
That's when she decided it was time for the family to see a therapist. "It's a question of what's normal for my kids," she explains.
O'Leary is right. Mental health experts say the first steps in recognizing possible mental illness in your children are to know their habits and patterns, to notice when they deviate from them, and to create an environment in which they feel comfortable talking with you.
Instead of asking your teen to talk, share an activity that will give your child the chance to open up: Cook dinner together, walk the dog, take a drive, says Tara Niendam, an associate professor in psychiatry at the University of California at Davis.
"You just want to know how they're doing as a person. How are things going at school? How are their friends? How are they sleeping?" she explains.
As part of getting to know your teen, monitor and limit your child's social media activity, says Amy Barnhorst, vice chair for community mental health in the UC-Davis psychiatry department.
"Social media gives us this important window into what's going on in teenagers' lives," she says.
Once you know your child's baseline, you'll be more attuned to signs of mental illness: changes in your child's everyday life that last more than a week or two.
Be aware of disruptions in sleep, appetite, grades, weight, friendships - even hygiene.
Maybe your son is spending even more time than usual alone in his room. Perhaps your daughter, who is particular about her appearance, stops wearing makeup and isn't showering.
"It's really when you see kids falling off the curve in every sphere of their lives," Barnhorst says. "They're having problems with their academics, problems with their family, problems with their friends, problems with their activities."
Remember, You're looking for changes in many aspects of your child's life that last for a few weeks, not the typical but temporary sadness that comes with a breakup or the unfortunate mouthing-off you get when you ask your kid to clean his room
If your child still has the same friends and is participating in the same activities, unpleasant behavior could just be teenagers going through growing pains," Barnhorst says.
But some behavioral changes could indicate a deeper problem. For instance, teenagers with depression may be more irritable than usual, Adelsheim says. They might snap at friends or even the family dog, he says.
"Young people will talk about their fuse being shorter than normal," Adelsheim says. "Things that normally wouldn't bother them do bother them."
When you become worried that your child's behavior may indicate something more serious, offer your child love and support - and seek help, experts say.
(And avoid such phrases as "What's wrong with you?" and "Snap out of it" when talking with your kids, Niendam advises.)
If your child threatens suicide or you think he's in imminent danger, take him to the emergency room. If there's no immediate danger, start with your child's pediatrician or primary care physician who can either address the problem directly or refer you to a mental health specialist.
This is where it could get tricky.
You may face a long wait - especially if you live in a rural area - and may find that many specialists aren't accepting new patients. Barnhorst suggests asking your health insurer for a list of in-network therapists, psychologists and psychiatrists. Then hit the phone and hope for the best.
"One of the most serious problems we have in this country on the mental health front is the lack of access to care," says Victor Schwartz, chief medical officer of the Jed Foundation, which works to prevent suicides in teens and young adults.
Another option, he says, is to ask nearby universities whether they have mental-health clinics that train students and see patients.
Niendam suggests connecting with your local chapter of the National Alliance on Mental Illness (nami.org), an organization of people whose lives have been affected by serious mental illness. "If you're struggling, you can meet other parents and ask their advice," she says.
This story was produced by Kaiser Health News, an editorially independent news service of the Kaiser Family Foundation.