In the past 30 years, there’s been a dramatic decline in the achievement and psychological health of American children.

That’s not just hyperbole, said Dr. Leonard Sax, a practicing physician, PhD psychologist, and the author of The New York Times bestseller, “The Collapse of Parenting.” It’s the sad result, he told LifeZette, of parents who let their kids call the shots.

“Devices with internet access should be used in a public space, such as the kitchen.”

Activities with same-age peers now commonly displace family activities. Children today often choose what’s for supper. They choose which social media they will engage. They often choose their bedtime. Sometimes they even choose their schools.

“These factors and related influences have led to children and teenagers being less resilient, less physically fit, and more likely to become anxious or depressed — and far more fragile — compared with kids from the same demographic 30 years ago,” Sax said.

Parents today are unsure of their role. “They ask, ‘Should I be my child’s most trusted confidante? My child’s best friend? But if I am my son’s best friend, how can I tell him that he is not allowed to play violent video games?'”

Sax, who is based in Exton, Pennsylvania, shared more of his thoughts with LifeZette in an interview.

Question: What does it mean to treat your child like a grown-up?
Answer: I find many parents who are confused about their role as parents. They think that good parenting means letting kids decide. In some domains, that’s true. But in other domains, it’s not true. For example, should you let your daughter take her mobile phone to bed with her?

Related: Social Media Zaps Our Empathy

My answer is: No, you should not let your daughter take her mobile phone to bed with her. At 9 at night, you the parent take the device and you plug it into the charger, which stays in your bedroom, the parent’s bedroom. Your kid can have it back the next morning. (And again, that’s not just my opinion; the official guidelines from the American Academy of Pediatrics recommend no mobile phones in the bedroom.)

This is your job. It’s not reasonable to put this burden on your son or daughter. What is she supposed to say, when her friend asks her tomorrow in school, “Hey I texted you last night at midnight, how come you didn’t answer?” Do you expect her to say, “Well, I thought it was more important for me to get a good night’s sleep than to answer your text?” It’s not plausible to expect a child or teenager in this era to say such a thing. You have to allow her to say, “My evil parents take my phone every night at 9 and they don’t let me have it back until the next morning!”

Who do you think would win the Presidency?

By completing the poll, you agree to receive emails from LifeZette, occasional offers from our partners and that you've read and agree to our privacy policy and legal statement.

You have to be the evil parent. Turn the devices off at 9 p.m. Devices with Internet access — the laptop, the iPad and the smartphone — should be used in a public space, such as the kitchen. The bedroom should be primarily for reading and for sleeping.

Some parents push back when I make such suggestions. “My daughter will be going away to university in three years,” one mother said to me. “I won’t be there to supervise how she uses her devices, or to switch off her phone at 9 p.m. So shouldn’t I let her get used to that freedom now?” My answer is: If you inculcate good habits now, your daughter (or son) will be at least somewhat more likely to continue those good habits at college.

Related: Social Media Is Not Your Friend

On the other hand, if your daughter gets in the habit of spending hours a night on social media, or texting after midnight; then it’s not very likely that when she arrives at university, she will say, “Ah, now that I am at the university, I will renounce my former unproductive ways and become more virtuous, even while my peers are indulging themselves.”

Wise parenting means recognizing sometimes your kid should make the decision, sometime you should, and what the difference is between those two.

Q: Surely there is a benefit to being “friends” with your children, isn’t there?
A: It’s easy to get tripped up by the choice of words. Of course you want to be friendly and loving with your child. Of course you want your child to be comfortable confiding in you. Of course you want to spend as much time as possible doing fun stuff with your kid. But a friend is a peer. A friend can’t give orders. A friend can’t say, “I will not allow you to pig out on ice cream right before supper.” Only a parent can say that. A friend can’t say, “I’m not letting you take your phone to bed with you, because it’s more important for you to get a good night’s sleep than to be up texting your friends at midnight.”

“If you’re doing your job as a parent, there will be times when your child pushes back and is upset with you.”

Only a parent can say that. I have found that some parents conceptualize themselves as their child’s best friend, and then they find it harder to do the things that only parents can do – such as enforcing a reasonable bedtime — because a friend can’t give orders.

Other critics have said that good parents never give orders. Good parents just offer suggestions, and let kids decide. Again, there are some domains where that might be reasonable. But in other domains, such as whether it’s OK to have a big bowl of ice cream right before supper, parents sometimes have to act like parents, not like best friends.

Don’t be afraid to do your job. If you’re doing your job as a parent, there will be times when your child pushes back and is upset with you. That’s OK. It’s not the end of the world.

Q: Can the rising levels of ADHD, depression and anxiety among young people really be traced to parents who let their kids call the shots?
A: It’s complicated. There are many ways in which parents’ uncertainty about their role has led, unintentionally, to more kids being diagnosed and treated for conditions such as ADHD, depression and anxiety, all of which are much more common among American children and teens than was the case 25 years ago.

Related: How My Son Made My Day — and It’s Not Even Mother’s Day Yet

One of the basic duties of a parent is to ensure that the child gets a good night’s sleep rather than staying up late playing games.  That’s not a new idea. But 30 years ago, we didn’t have Internet-enabled devices that make it easy for kids to play online with other kids at 2 a.m. Now we do. This means that parents have to be more assertive of their authority than in previous decades. But many American parents have abdicated their authority rather than asserting it. The result is: boys playing video games at 2 a.m., girls staying up past midnight texting their friends on their cell phones, or uploading their selfies to Instagram.

Based on my experience over the past 30 years as a physician and a PhD psychologist, I believe that sleep deprivation is one reason why American kids today are more likely to be diagnosed with ADHD, compared with American kids three decades ago. And the failure of parents to assert their authority is a big part of the reason that American kids are getting less sleep than they used to.

Q: How about the rising levels of obesity among young people? Who takes the blame for that?
A: This abdication of authority by parents is one factor driving the rise in the rates of obesity among American children and teenagers. It’s not the only factor, but it is one factor.

I was speaking to parents in Chappaqua, New York, an affluent suburb in Westchester County, north of New York City [where Bill and Hillary Clinton have a house]. A well-educated professional couple told me how they had carefully prepared a healthy and nutritious supper for their daughter and son. When the two kids came home, they said “Yuck. We don’t want to eat that. Can we just order pizza?”

Related: The Biggest Cause of Our Kids’ Weight Gain

The dad ordered pizza to the kids’ specifications. I asked him: “Why? Why not just tell them, ‘This is what’s for supper?'” He answered, “I don’t believe in using starvation as a means of discipline.”

I said, “They’re not going to starve. If they’re hungry, they’ll eat it.”

In 1971, only 4 percent of American kids were obese. Today, 17 percent of American kids are. Forty years ago, American parents (usually Mom) made supper, and kids either ate it or went to bed hungry. In that era, if Mom made supper and the kids didn’t want to eat it, she would most likely say, “This is what’s for dinner. If you’re hungry enough, you will eat it.” She didn’t order a pizza for her kids just because they didn’t approve of the supper she had prepared. Forty years ago, pizza, French fries, potato chips, and ice cream were occasional treats. Today, in some homes, they are daily fare.

Q: What can parents do to change their children’s behavior?
A:
The older the child, the harder it is to make a big change. But as long as your child is living at home with you, it’s not too late. Don’t try to be cute. Sit down with your child and explain that you’ve been doing some things wrong as a parent. There will be some big changes, starting today. No video games and no social media until all the homework is done and all the chores are done. No screens in the bedroom. Phones will be switched off and placed in the charger, which stays in the parents’ bedroom, no later than 9 p.m. The first day you make this announcement, there may be an explosion and shouting.

The first week, you may get a cold shoulder and angry stares. But if both parents stand their ground, after six weeks your child will be happier and healthier, and the family will be on much more solid ground.