Sudden Behavior Changes in Kids: What Do They Mean?

By James Lehman, MSW

Whether we like it or not, kids change. Their behavior, their attitudes, their likes, and their dislikes. These changes occur throughout childhood but are most pronounced during adolescence.

Kids can suddenly lose interest in the things they used to play with. One day your child is playing with dolls or trucks, and the next, they want to wear nail polish and make-up and to have a cell phone.

Many of these changes are part of normal childhood development and are to be expected and even encouraged.

Related content: Sudden Behavior Changes in Kids: 7 Things You Can Do Today

Nevertheless, parents need to be aware that sudden changes can also stem from trauma, substance abuse, or other problems.

Behavior Changes from Bullying

Ridicule and rejection, especially in adolescence, can be very, very traumatic for kids. If you live in an urban, suburban, or even rural area, often there are groups and bullies in school who hold a lot of sway over the other students.

I’m not talking about dangerous gangs with guns like you see in the movies. I’m talking about groups of kids who hang out together and target other students as their victims, usually via public ridicule or physical intimidation.

Know that once a bully targets your child, they are probably doing so every day. Whether it’s ridicule or physical abuse, it’s terrible for kids and often results in severe mood changes.

If you suspect your child is being bullied, you may see a difference in their grades and their attitude. They may be more irritable and more easily frustrated.

Many kids won’t talk with anyone about the fact that they’re being picked on. Instead, they withdraw from the world. Their daily life is very painful for them, and so their coping skills become withdrawal and avoidance.

Pre-teens who are bullied often won’t want to get dressed in the morning. And you’ll start to hear them say, “I don’t want to go to school.”

For more on bullying, including what to do about it, read My Child is Being Bullied—What Should I Do? and The Truth About Bullies.

Behavior Changes from Substance Abuse

One of the things parents often described to me in my office was how their child changed overnight. Their grades went downhill. They became more secretive. They withdrew from family life.

The speed of the change is what was most notable.

Your child will undoubtedly undergo some pretty major changes between the ages of 10 to 18, and adolescents might even change fairly dramatically over any given six-month period. But if substance abuse is involved, behavioral changes can occur very quickly. Perhaps within a week or two.

If substance abuse is occurring, you will likely see your child stop or resist doing homework. A drop in school grades often shows up first because it’s clear and fairly immediate. Your child gets graded on his or her performance in school daily so the change in their performance is measurable.

If one month your child gets an A, and the next month he gets a D, that’s a pretty clear sign that something is going on, especially if you notice his grades going down in all subjects.

If he loses interest in things like sports or his old friends, it’s another indication that substance use may be involved.

Usually, when kids get involved with substances they start by using them intermittently, on the weekends, or at a certain friend’s house. Some kids experiment for a bit and then walk away, and get on with their lives.

But others experience a sense of relief from the pressures of adolescence when using substances. Those kids are at risk for deeper involvement.

Drugs and alcohol become an increasingly primary part of their lives. They stop caring about the things they used to care about. It may not matter to them if they’re neatly dressed and groomed anymore. They will go from being concerned about school and willing to work to achieve good grades to saying, “Ah, who cares if it’s an ‘A’ or a ‘B’? In other words, they start making excuses and justifications for the fact that their grades are falling.

Don’t get me wrong, sometimes kids do have a bad experience with a teacher or a hard time with a certain subject. But if that’s the case, you’ll see their grades fall in that specific course—it won’t result in a global, or overall, effect.

Realize that if your child is undergoing a personality change due to substance use, it usually impacts every facet of their life. You’ll see it with their attitude toward their siblings and toward you. A previously honest child will begin lying more and keeping secrets.

Sometimes things begin to go missing around the house, especially money and valuables.

You’ll see your child start to gravitate toward a different type of friend. These kids won’t be achievers. They aren’t the kids who care about their grades or are involved in sports. They aren’t the kids who want to be involved in any sort of family activities. Their primary interest is to party on the weekends and after school.

Sadly, you will see all these changes when substance abuse starts to take over more and more of your child’s life. Eventually, the day comes when if they can’t get high or drink, they don’t feel they have anything worthwhile to do.

If you suspect that your child has a substance abuse problem, I think you need to be very clear in your language to them. Let them know that they have to take responsibility for it. If that means going with you to see a professional who can assess them, you have to make your expectation clear.

I recommend that kids in this situation see a qualified substance abuse counselor, preferably one who deals with adolescents.

If your child refuses to go, you can say, “Okay, then kiss your cell phone goodbye. And kiss the computer goodbye too, we’re taking it out of your room. Kiss the car goodbye.”

I think you need to be very black and white about your expectation that they take responsibility for this problem. Be strong. I don’t mean that you should be nasty or hostile, just take a stand, state your expectation, and stick with it, no matter how much complaining or blaming or arguing they throw at you.

Substance abuse is a fight worth fighting, so you have to try to stay strong.

Sexual Abuse

You will also see a child’s behavior change when they have been sexually abused, either by a stranger or someone they know. This personality change is often drastic. A child who has been molested often becomes more isolated and withdrawn. Their grades go down and they become more fearful of people and places.

If you ever suspect that your child has been sexually abused, immediately report whatever you know to the police, and have your child seen by medical and mental health professionals right away.

Any time your child’s behavior or personality changes drastically overnight, it’s important to have them evaluated immediately by a professional to rule out any physical reasons for the change, whether it’s from substance abuse, trauma, or the onset of depression or anxiety.

Whether changes in kids are slow or sudden, parents have a hard time with the fact that they can’t protect their children once they leave home in the morning. Once your kids walk out the door, you simply can’t insulate them from the kind of culture that is out there: the violence, the sexualization, and the glamorization of criminal behavior. The rub is that if you fight your child’s need to individuate, you’re fighting their every instinct—and it’s a losing battle.

So it’s not whether or not they individuate that you can influence, it’s how they individuate and what the rules of their rebellion are going to be that can make your family life easier. There are no guarantees in life, but as parents, we have to try our best to keep our children on the right path to adulthood.

Related content: Parenting Teens: Parental Authority vs. Peer Pressure