Normal Teenage Behavior vs. Signs of Mental Illness

Adolescence: It’s a time rife with hormonal surges, big decisions, and an intense desire (and need) to break away from the role of a child. Many parents notice that their kids are moody, impulsive, and sleeping at different times than they used to. For most teens, these are normal parts of growing up. For others, however, they could be the early signs of mental health conditions such as anxiety, depression, and bipolar disorder.

How can you tell the difference? Here’s a guide to normal teenage behavior vs. signs of mental illness. As always, however, if you have questions or concerns about your adolescent’s development, it’s important to consult with a physician.

Mood Swings, Anger, and Irritability

Mood swings are common during the pre-teen and teen years. Girls are more likely to vacillate between happy and sad, and boys are more likely to swing from happy to angry, but teens of both sexes can experience a wide range of emotions in a day; in some cases, they can swing from positive to negative emotions in an hour or even in minutes! How do you know whether your teen’s moodiness is normal teenage behavior or a potential mental health issue?

One way to tell the difference is the intensity of the emotions. If your teen is quick to tear up or get irritated over what you consider nothing worth crying or complaining about, that’s likely par for the course of adolescence. If, however, your child is excessively angry or destructive, that’s not normal. Neither are long periods of intense sadness or hopelessness. While positive emotions don’t usually cause alarm in parents, you should be aware of any manic behavior, particularly if it’s followed by a period of depression.

Impulsive, Risky Behaviors

A teen’s frontal cortex is not fully formed, and this can be frustrating for teens and adults alike. A teen often underestimates risks and overestimates his or her abilities. Teens often act impulsively, not pausing to think about the risks and benefits of various behaviors. Many teens believe that they are invincible and that “it won’t happen to me,” whether “it” is a car accident, a teenage pregnancy, or getting caught doing something illegal or dangerous. Teens can often feed off of each other’s dares and challenges, as evidenced by the recent Tide Pod Challenge that made its way through social media.

Some of this is normal teenage behavior. Talking to your child about making good choices and giving him or her gradually increasing levels of responsibility can help them get through this time. If your teen is very impulsive, however, and isn’t able to control his or her reckless behavior, that is a potential mental health red flag. Getting arrested, getting into more than one minor car accident, and being caught driving under the influence of a substance are all behaviors that warrant concern.

Differences in Appetite and Weight

As your teen finishes growing, he or she might put on weight in different places. “Baby fat” tends to dissipate during the early teen years. Some teens will become overweight due to diet, a lack of activity, health issues, or genetics. Many teens are concerned by these changes. Some will develop eating disorders, first in an effort to control weight, and then because they cannot control the mental processes that allow this type of disorder to continue. Know the signs of anorexia and bulimia, and be on the watch for any symptoms that you can see in your teen.

Anxiety and depression can also cause weight fluctuations that aren’t related to normal development or an eating disorder. A teen suffering from these mental health conditions might have no appetite at all and might lose weight. Other teens with these illnesses might overeat, leading to weight gain. Changes in weight can also lead to poor self-esteem. It’s not uncommon for a teen with depression to overeat and gain weight, then develop an eating disorder. If you are concerned about your teen’s weight or eating patterns, consult his or her physician.

Differences in Sleeping Patterns

You might have noticed when your teen entered adolescence that he or she wanted to stay up very late and sleep in. On weekends and during school breaks, this is normal teenage behavior. A teen’s circadian rhythm changes during the pre-teen and teen years, and they naturally find it more difficult to go to bed early. Another factor is that many teens are using smartphones and tablets late at night; the blue light emitted by these devices can interfere with melatonin production, causing insomnia. These issues can often be solved by removing the devices from their bedrooms after a specific time at night.

If your teen is having sleep disturbances and isn’t sleeping much at all, however, there might be a problem at play. For example, a teen with anxiety might not be able to wind down easily. Another issue is that depression can cause a teen to sleep many more hours than the typical teen needs; the lack of energy and overwhelming fatigue can cause a teen to stay in bed most of the day, even to the point of making it impossible for them to attend school. These problems should be addressed by a physician or mental health professional.

Teenage Apathy and Boredom

Many parents lament that their teens are bored and not interested in doing anything. If the issue is that they’re more interested in playing video games, listening to music, and texting with their friends than they are in doing schoolwork or getting a job, then it is likely just a case of teens being teens. If, however, your teenager has lost interest in the friends, activities, and interests that they used to enjoy, there could be a larger underlying problem, such as depression or substance abuse. Talk to your teen to find out if there is an issue that needs to be addressed.


Parenting a teen isn’t easy, and it can be difficult to determine whether annoying, troubling, or frustrating behaviors are par for the course or a red flag. One tip for deciphering signs of mental illness from normal teenage behavior is to to keep communication open with your teen. With an open line of communication, your teen will feel comfortable opening up to you about what’s going on in their life and how they are feeling. If you suspect that your teen might be suffering from a mental health disorder, the next step is to consult with a mental health specialist