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23 Red Flags In Teenage Behavior

As parents, we’ve all been there—our once sweet, innocent child suddenly morphs into a moody, eye-rolling, door-slamming teenager, and we’re left wondering what on earth just happened. 

Welcome to the turbulent world of adolescence, when hormones, peer pressure, social pressures, physical changes, and emotional growth collide, leading to significant changes in emotions and behaviors.

Even though dealing with teenage years may feel like walking through a dense forest, red flags can serve as our compass, guiding us toward early intervention and even professional help if necessary.

red flags in teenage behavior teen in depression isolation

Red flags in teenage behavior

Here are some major red flags that may indicate problems in a teen.

  1. Drop in academic performance
  2. Excessive isolation
  3. Disruption in sleep patterns
  4. Lose interest in social activities or extracurricular activities once enjoyed
  5. Mood swings or excessive moodiness
  6. Irritability from time to time
  7. Aggressive behaviors
  8. Excessive anger
  9. Excessive risky behaviors
  10. Unusual rebellious behavior
  11. Secretive behavior
  12. Avoidance behaviors
  13. Social isolation
  14. Extreme weight loss or dramatic weight gain
  15. A lack of personal hygiene
  16. Impulsive behavior
  17. Loss of appetite
  18. Feelings of worthlessness or hopelessness
  19. Covering up arms in the summer
  20. Excessive weight concerns
  21. Extreme dieting
  22. Delinquent behavior
  23. Risky sexual behavior

Issues behind the behavioral changes

Every warning sign can have several causes. Therefore, do not jump to conclusions after observing only one behavioral red flag. 

An isolated red flag might be a mere coincidence.

Some behaviors may also be considered typical teenage behavior. For instance, a teen’s mood swings are normal teenage behavior, but extreme mood shifts are not.

Excessive red flag behaviors or multiple ones often indicate that the teen is grappling with issues or challenges.


Here are some common signs of clinical depression in teens​1​, a serious mental health disorder.

  • Excessive sleeping or insomnia
  • Loss of interest in once enjoyable activities
  • Appetite loss
  • Lack of engagement with daily life
  • Feelings of guilt or worthlessness
  • Chronically low mood
  • Isolation from family members or stop spending time with your teen’s friends
  • Suicidal thoughts or talk of suicide

General anxiety disorders and other mental health disorders may show similar symptoms.

If you observe these signs or abrupt changes in behaviors, seek help from mental health professionals who can properly diagnose them.

red flag behaviors sad teenager sitting


Self-injurious or self-destructive behavior is direct and deliberate bodily harm without suicidal intent. Self-injury typically involves cutting or carving the skin to decrease negative emotions or as a cry for help​2​.

Some common warning signs include

  • Unexplained wounds or scars, often in patterns
  • Hiding the skin, such as wearing long sleeves on a hot summer day
  • Being alone in the bathroom or bedroom for an extended period
  • Sharp objects such as knives or razor blades hidden in possession
  • Frequent accidental injuries
  • Self-criticism
  • Feelings of helplessness or hopelessness

Self-harm is one of the symptoms of mental illness, such as borderline personality disorder​3​.

It is also associated with adolescent sexual and physical abuse. Seek help from a mental health expert immediately if you notice these in your teen’s behavior.​4​

Eating Disorder

Drastic changes in weight are common signs of eating disorders such as anorexia nervosa and bulimia nervosa.

Major signs of eating disorders are

  • Obsessive weight measuring or calorie counting
  • Patterns of weight loss
  • Intense fear of gaining weight
  • Negative body image

Many teenage girls are concerned about being overweight and may diet inappropriately. This is normal behavior for adolescents, and most do not have an eating disorder​5​. But don’t hesitate to speak to your family health practitioner if you have any doubts.

Substance abuse

Alcohol and drug abuse problems are prevalent among young people in the US, and most drug use begins during the teen years​6​. The substance abuse problem often co-occurs with a mental health condition.

Early intervention can be sought if parents can recognize the potential red flags.

  • Red face, bloodshot eyes, or breath odors of alcohol​7​
  • Lack of personal hygiene
  • Irritability
  • Extreme rage or mood swings
  • In possession of illegal drug
  • Difficulty focusing in school or completing assignments
  • Secretive behavior, such as hiding in the bathroom or bedroom for long periods
  • Signs of depression, bipolar disorder, or general anxiety disorder​8​

Also See: Coping Skills for Teens

Abusive relationship

Research indicates that a significant proportion, approximately 45%, of adolescents aged 13-14 have experienced abuse within their dating relationships.​9​

Vigilance from parents plays a crucial role in identifying any distress signs in their teenager’s behavior. But teaching their teens about potential warning signs is also important.

For many teens, dating relationships are a novel experience, and they may not easily discern what constitutes abuse. Here are some types of dating violence teens must be aware of.​10​



  • Sexual abuse
  • Sexual coercion
  • Controlling behavior, such as monitoring the whereabouts of a partner or controlling their activities
  • Emotional abuse, such as creating a “hate” website about a former partner


  1. 1.
    Fava M, Kendler KS. Major Depressive Disorder. Neuron. Published online November 2000:335-341. doi:10.1016/s0896-6273(00)00112-4
  2. 2.
    Nock MK. Self-Injury. Annu Rev Clin Psychol. Published online March 1, 2010:339-363. doi:10.1146/annurev.clinpsy.121208.131258
  3. 3.
    Hodgson S. Cutting through the Silence: A Sociological Construction of Self-Injury. Sociological Inquiry. Published online May 2004:162-179. doi:10.1111/j.1475-682x.2004.00085.x
  4. 4.
    Hawton K, Saunders KE, O’Connor RC. Self-harm and suicide in adolescents. The Lancet. Published online June 2012:2373-2382. doi:10.1016/s0140-6736(12)60322-5
  5. 5.
    Rosen DS. Identification and Management of Eating Disorders in Children and Adolescents. Pediatrics. Published online December 1, 2010:1240-1253. doi:10.1542/peds.2010-2821
  6. 6.
    Burstein M. Use and Abuse of Alcohol and Illicit Drugs in US Adolescents. Arch Gen Psychiatry. Published online April 1, 2012:390. doi:10.1001/archgenpsychiatry.2011.1503
  7. 7.
    Saini G, Prabhat K, Gupta N. Drug addiction and periodontal diseases. J Indian Soc Periodontol. Published online 2013:587. doi:10.4103/0972-124x.119277
  8. 8.
    Simon NM. Generalized Anxiety Disorder and Psychiatric Comorbidities Such as Depression, Bipolar Disorder, and Substance Abuse. J Clin Psychiatry. Published online April 2009:10-14. doi:10.4088/jcp.s.7002.02
  9. 9.
    Fox CL, Corr ML, Gadd D, Butler I. Young teenagers’ experiences of domestic abuse. Journal of Youth Studies. Published online March 25, 2013:510-526. doi:10.1080/13676261.2013.780125
  10. 10.
    Zweig JM, Dank M, Yahner J, Lachman P. The Rate of Cyber Dating Abuse Among Teens and How It Relates to Other Forms of Teen Dating Violence. J Youth Adolescence. Published online February 15, 2013:1063-1077. doi:10.1007/s10964-013-9922-8


    * All information on is for educational purposes only. Parenting For Brain does not provide medical advice. If you suspect medical problems or need professional advice, please consult a physician. *