Dear Dr. Wes & Samantha: We want more information about teenage lying that borders on the pathological. In addition to being bright and talented, our 17-year-old daughter lies, cheats and steals. She’s exhibited secretive behavior since childhood, including hiding candy in her bed. In adolescence she was diagnosed with anxiety and later ADD, and on medication for both now. She lies about almost everything from big things to small, inconsequential things. We’ve caught her cheating on schoolwork. She takes things from her friends. When confronted she initially plays dumb, then gives a completely irrelevant comment that does not explain anything. In addition to the lying she does not respect any personal boundaries, feels free to make use of items belonging to anyone in the household and acts as though rules do not apply to her. She is a pretty and popular girl but headed for more serious trouble.

— Readers from Northern Virginia

Samantha: I understand your concerns about your daughter’s lies. Lies are part of social exchange in our culture. We lie about liking awful presents. We lie to telemarketers and say we can’t talk because we have company. We lie to friends about their “adorable” haircuts. However, your daughter has reached a point where her lying is frequent and hurts others. She has a serious problem and may be ruining her relationships for some time to come. If you cannot help her change this behavior while you still have legal guardianship, it may never change.

As I understand, a pathological liar is someone who lies in spite of him/herself. I have no way of knowing whether your daughter fits this description, but I would want her to meet with a professional for diagnosis and treatment. Remember to check with the psychologist to make sure she’s actually attending her sessions. Given her history, I’d want confirmation.

Dealing with this requires finding the balance between being supportive and firm. Tell her you love her often and that you’re sending her to therapy to save her from herself and the damage she’s doing. When she lies, explain how damaging it could be to lose the trust of people she cares about. You have the right to be stern and punish her when she lies or breaks the rules, but always remember to keep the balance of things you say to your daughter tipped toward the positive. I’m confident that you can see the good in her, because you so many assets in your letter.

Finally, I hate to downplay your other concerns, but some of those behaviors — hiding candy, cheating on schoolwork, using family member’s belongings without asking — are normal teen behavior. For example, I checked with a couple friends, and almost all of us have hid our candy on occasion. Also, though I believe it’s wrong to cheat on schoolwork, many of my classmates have done it. That doesn’t make it right. But neither is it pathological. Finally, I am guilty of using my sister’s and mom’s belongings without asking. Extreme versions of these behaviors are a different story, but on these issues, your daughter may not be as bad off as you fear.

Wes: Few young people have as hard a time as those with both ADD and anxiety. About 25 percent of people with one diagnosis also have the other, and they’re among the most tortured folks I treat. Those symptom sets simply don’t play well together, and it takes a very experienced therapist and prescriber, plus early intervention, to get it to come out right.

Unfortunately for your daughter, a diagnosis is not the same thing as an excuse. What I’m curious about is how in the world she’s gotten this far without massive retaliation, from you, her friends, school, the cops. As Samantha notes, you’re almost out of time with her as a minor, yet she seems undaunted by consequence. So something is really wrong here, and it’s up to you to correct it, fast.

My approach is slightly different than Sam’s. I’d be playing hardball right now. She can’t afford anything less than super-tough love. I’d turn her whole world into a contingency plan for telling the truth and playing fair. Does she have a car? A cell phone? A room in your house? A metro pass? Does she plan to go to college on your dime? If so, now would be a great time to link all those goodies to pro-social behavior. Young people who lie, cheat and steal are violating a core social contract with their families and community. Somehow she hasn’t gotten that message, so I’d start selling off her property, ASAP. That’s what eBay is for. You can stop when she stops, and see what happens. She’ll push back. Maybe move out. Get in trouble. When she does, DO NOT under any circumstance lawyer up or bail her out. She’s bought her ticket. Now she gets to ride. I won’t tell you this is easy, but if things are as bad as you say, you have to take decisive action.

Finally, you need to do all this under the treatment of a good therapist. However, I wouldn’t waste a dime on individual therapy. You (both parents) have to be involved directly. Of course you’ll find lots of therapists out there ready to take your money and see your daughter ever week. But in your case, therapy needs to be about supporting you in maintaining a hard line. Once she’s operating like less of a sociopath, the therapist can let her discuss what she prefers. Until then, you have to take her down a few pegs, before someone comes along (read: the court) and enforces social convention for you. I’ll send you a couple of names in your area. They know how to deal with these sorts of situations.

— Dr. Wes Crenshaw is a board-certified family psychologist and director of the Family Therapy Institute Midwest. Samantha Schwartz is a senior at Lawrence High School. Opinions and advice given here are not meant as a substitute for psychological evaluation or therapy services. Send your questions about adolescent issues (limited to 200 words) to doubletake@ljworld.com. All correspondence is strictly confidential.