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Knowing the Difference Between Normal Teenage Behavior and Possible Mental Health Disorders


Knowing the difference between normal teenage behavior and possible mental health disorders

(855) 940-6229 Verify Insurance Typical teenage behavior patterns can change dramatically, often in what feels like the blink of an eye for their parents. Teenagers are known to be moody, complete with mood swings and odd behavioral changes. They may engage in more rebellious behaviors, including sneaking behind their parent's backs or trying out substances.  Many psychiatric disorders also emerge for the first time in adolescence, which means that parents may need to remain on the lookout for changes in a teen's behavior that could signify a severe mental health problem.1

What is Normal Teen Behavior?

There are various changing behaviors in teens that are absolutely normal: behaviors shared by a large portion of their cohort and which may indicate nothing more than typical adolescence.

1. Changed Sleep Schedules

Teens naturally shift to a delayed Circadian rhythm.2  By nature, they tend to want to head to bed around one in the morning and may naturally sleep until around ten the following day.  Unfortunately, most teens must adhere to a schedule that does not allow them to keep up with their natural body clocks. With many public schools starting at 8 am or earlier, many teens are fighting their bodies' natural sleep cycles. That means they may appear to sleep more often or look more tired during the day.  Many teens will take a mid-afternoon nap or sleep through classes—especially those they consider tedious—to help compensate for lost sleep at night.

2. Rebellious Behavior

Typical teen behavior naturally becomes more rebellious. While disciplinary style, including how much feedback and interaction parents allow, may impact overall rebelliousness, teens may also rebel due to their desire to develop their own identity apart from the family unit.3 Teens want the ability to make their own decisions, and they may push back against the behaviors their parents once prevented to showcase who they are or who they want to be. As part of that rebellious behavior, many teens will show signs of declining grades as their priorities shift. Children who did well in grade school or even early middle school may not naturally transform into teens who demonstrate high performance in school.

3. Lying

Teens may lie to their parents for any number of normal, completely natural reasons. Teens may lie because they fear punishment or want to increase privacy. Sometimes, teens will lie about relatively inconsequential things to see if they get caught and the potential consequences.  They may also lie to cover up embarrassing behavior, including things like low test scores or failing to turn in homework. In addition, teens may lie to get to do the things they want, particularly if they know that a parent will punish them for engaging in certain behaviors or prevent them from doing some of those things.

4. Defiance

In many ways, defiance is an extension of rebellious behavior. Teens may push back and test their parents to reestablish their boundaries as they seek to create that personal identity. Defiance may seem frustrating for parents, but over time, it can help teens get a better idea of who they are and where they stand on common issues.

5. Irritability

Teens often experience dramatic hormone changes, frequently within a very short period. They may also experience immense stressors. Most people would not willingly go back to middle or high school, even if they thrived in that environment at that time.  Teens are often under a great deal of pressure. They may juggle school responsibilities along with clubs and activities, after-school jobs, and responsibilities at home, all while dealing with the emotional upheaval that comes along with adolescence. Those changes and challenges can naturally result in increased irritability for many teens. They may seem "moody" or "unapproachable" to their parents.

6. Withdrawal

Some withdrawal may be natural for some teens. As they work to establish those separate identities, they may naturally shift their support groups from family members to friends. They may also want more private time to deal with their concerns or work on their projects. A certain level of withdrawal, including spending more time on social media or with technology, may be a natural result of adolescence. Knowing the Difference Between Normal Teenage Behavior and Possible Mental Health Disorders; blonde teen in a black hoodie stands in a green dimly lit tunnel with her hair covering her face

Signs of Mental Illness in Teens to Watch Out For

While considerable changes in personality or behavior are normal for many teens, parents need to know what signs to watch out for so that they can identify signs of mental illness early and seek treatment if needed.

1. Losing Interest in Preferred Activities or Socialization

As teens reach those adolescent years, their interests may naturally shift. A formerly-athletic child may decide that they do not want to participate in high school sports. A quiet teen might want to focus on their personal writing or artistic efforts rather than submitting content to the school literary magazine or art show.  However, if teens suddenly lose all interest in activities or socialization, it could indicate a deeper problem. Teens struggling with anxiety or depression may withdraw from their friends and engage in risky behavior. In addition, bullying can cause teen depression and adolescents to withdraw from the activities they once enjoyed.

2. Sleeping Excessively

Teens may sleep a lot. However, a young person who naturally wants to sleep until 1 or 2 in the afternoon on the weekend should be up and engaged at other times. Parents who notice their teens staying in bed all day and night may want to screen their troubled teen for further potential signs of mental illness.

3. Obvious Signs of Restlessness or Feeling "On Edge"

Teens may suffer from higher degrees of anxiety than ever before. As many as 1 in 5 youth, including children under 13 and adolescents between 13 and 18, experience clinically heightened anxiety levels.4 Many of those teens will show symptoms of restlessness. They may have a hard time sitting down, or they may snap at parents, caregivers, and siblings over minor issues. Teens may also show signs of restlessness or being on edge when struggling with addictive behaviors. Since almost 40% of teens between 12 and 17 reports having used at least one illicit drug in their lifetime, parents may want to take careful note of those behaviors.5

4. Increased Academic Struggles

In many cases, increased academic struggles can indicate a serious problem for adolescents. While grades may naturally fall as teens' interests shift to other areas, parents should pay careful attention to patterns in their children's grades and academic behaviors. For example, if a student's grades suddenly fall in his favorite subject, that could serve as a warning that something more serious might have occurred. Parents should also note if a teen unexpectedly starts failing classes or dealing with more academic stress than usual.

5. Obvious Signs of Self-Harm

Around 27% of adolescents self-reported thoughts of self-harm over the course of a year.6 15% committed some type of self-harming act. Signs of self-harm in teens may include visible burns, bruises, or cuts and suddenly wearing long pants or sleeves that could cover up those marks. Parents should also note missing first aid supplies or other signs that their teens may suffer from a mental health issue.

6. Signs of Substance Abuse

Many teens will experiment with alcohol or some type of illicit drugs during their adolescent years. In many cases, teens will try out drinking or drugs socially with friends. Unfortunately, even a minor experiment can lead to more severe addiction. Signs of addiction may include withdrawal, red or glazed eyes, acting obviously high, engaging in excessively dangerous behaviors, or changing their schedules dramatically, often to get high or to get their substance.

7. New Anxieties and Worries

Many teens will withdraw from their parents or refuse to talk about their worries. However, parents may notice several obvious signs that teens find themselves dealing with new, heightened worries. They may ask questions about the same things repeatedly, including asking questions about scenarios unlikely to occur, or they may avoid certain topics. Parents may also notice their teens engaging in behaviors designed to protect against certain events, like putting together first aid kits or reviewing safety protocols.

8. Dramatic Changes in Weight

Teens often go through dramatic changes in appearance within a relatively short timeframe. They may grow rapidly, causing them to look thinner than usual. Girls may develop curves what feels like overnight.  However, parents should pay careful attention to dramatic changes in weight, which could indicate an eating disorder. 7 Both sudden weight gain and sudden weight loss could indicate an eating disorder.

9. Obsession

Obsessions can be common among teenagers, but it's important to recognize when they become unhealthy fixations. Signs of unhealthy obsessions include spending excessive amounts of time on a single activity or interest. They also include becoming defensive or hostile when questioned, and prioritizing perfectionism or control. Additionally, for parents seeking answers about their children's mental health, our What We Treat page on the treatments offered at MCAW can serve as a valuable resource.

Common Types of Mental Health Disorders in Teens

Teens can suffer from many of the same mental health disorders as adults. Many of those symptoms will become evident for the first time in adolescence.


Many teens may suffer from high levels of anxiety. Sometimes, that anxiety stems from external stimuli, including tests, sports, or friends. In other cases, however, teens may develop increased anxiety or worry over things they cannot control. Anxiety can quickly grow out of control, leaving teens struggling to engage in everyday activities or to unwind.


Many teens may struggle with depression, including bouts of irritability or anger. Depression in teens can cause several significant problems, including withdrawal from the things and people they usually enjoy spending time with. Teens may struggle to understand feelings of depression and cope with them effectively.

Eating Disorders

Teens often struggle with self-image issues, which can lead to anorexia or bulimia. Teens struggling with other mental health disorders may also have a higher risk of dealing with binge eating disorders. Some teens may have difficulty developing a healthy relationship with food, often due to a hectic schedule.

Substance Abuse Disorders

While a high percentage of teens may try drugs and alcohol, including  marijuana, some go from experimenting to a full-blown substance abuse disorder. Not only can substance use disorders cause a range of dangerous behaviors, but as teens become increasingly addicted, they may engage in several other dangerous behaviors to get the drugs they crave.  By eighth grade, more than 80% of adolescents have already tried alcohol.8 Unfortunately, teens struggling with another type of mental health disorder may have a higher risk of abusing substances when they try them.  Worse, teens may struggle with higher levels of addiction throughout their lives when they engage in those behaviors at young ages. Even vaping, often seen as inconsequential by many teens, can pose serious addiction problems.


ADHD, or attention deficit hyperactivity disorder, can make life difficult for many teens. Many teens who managed ADHD successfully in their primary school years may struggle more once they find themselves dealing with the demands of middle and high school. ADHD can interfere with academic performance and increase the risk of impulsive behaviors, including dangerous ones. However, ADHD is often over diagnosed due to the fact that teens may show symptoms of poor focus and attention for many other reasons, including exterior pressures.


In many cases, self-harm continues to go underreported since many teens will not admit to it. However, an increasing number of teens struggle with self-harming behavior, including cutting, burning, or otherwise harming themselves.

Suicidal Thoughts

Many teens and adolescents start thinking about suicide due to serious psychological challenges. They may struggle with suicidal ideation or even contemplate suicide. In extreme cases, teens may attempt suicide.

Borderline Personality Disorder

Symptoms of borderline personality disorder often start to show in adolescence. Teens may suffer from frequent bouts of anger or struggle between shifting extremes. Many patients with borderline personality disorder suffer from a high sensitivity to rejection and may engage in dangerous behaviors, including risky sexual behavior.

Attachment Disorder

Attachment disorders occur when teens and adolescents struggle to develop emotionally healthy connections with friends and loved ones. Many children will show signs of attachment disorders during their pre-adolescent years, but the symptoms may grow increasingly apparent during the teenage years.


Obsessive-compulsive disorder often appears as obsessive thoughts or repetitive behaviors. In many cases, teens may struggle to separate themselves from those behaviors or limit them. They may ritualize behaviors to avoid certain outcomes, including negative ones they have built up in their minds.

Treatment for Teen Mental Illness

Discerning the difference between normal teenage behavior and the potential for mental illness can be challenging. Behaviors like lying, defiance, and irritability are typically seen as normal teenage behaviors. However, if your teen loses interest in hobbies, becomes antisocial, or develops new obsessions these may be signs of mental illness.   Massachusetts Center for Adolescent Wellness offers day treatment and after-school outpatient program, as known as intensive outpatient programs, for teens who are struggling with mental health or susbtance abuse. If a teen you love appears to be struggling with symptoms of a mental health disorder, reach out to MCAW today. Our admissions team can answer any questions you may have and give you a better understanding of our outpatient program. Knowing the Difference Between Normal Teenage Behavior and Possible Mental Health Disorders; asian teenage girl with long hair and glasses sits on a couch during a therapy session with peers


  1. Giedd, Jay N, Matcheri Keshavan, and Tomas Paus. "Why do many psychiatric disorders emerge during adolescence? Nat Rev Neurosci. 2008 December
  2. Hagenauer, M. H., Perryman, J. I., Lee, T. M., & Carskadon, M. A. (2009). Adolescent changes in the homeostatic and circadian regulation of sleep.
  3. Frankel, J., & Dullaert, J. (1977). Is adolescent rebellion universal?.
  4. Racine, N., McArthur, B. A., Cooke, J. E., Eirich, R., Zhu, J., & Madigan, S. (2021). Global Prevalence of Depressive and Anxiety Symptoms in Children and Adolescents During COVID-19: A Meta-analysis.
  5. Lynskey, M., White, V., Hill, D., Letcher, T., & Hall, W. (1999). Prevalence of illicit drug use among youth: results from the Australian School Students' Alcohol and Drugs Survey.
  6. Stallard, P., Spears, M., Montgomery, A. A., Phillips, R., & Sayal, K. (2013). Self-harm in young adolescents (12-16 years): onset and short-term continuation in a community sample.,one%20act%20of%20self%2Dharm.
  7. Ward, Z. J., Rodriguez, P., Wright, D. R., Austin, S. B., & Long, M. W. (2019). Estimation of Eating Disorders Prevalence by Age and Associations With Mortality in a Simulated Nationally Representative US Cohort.
  8. Faden V. B. (2006). Trends in initiation of alcohol use in the United States 1975 to 2003.

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