Dramatic personality changes in teenagers: What’s typical and what’s not?


“Who are you and what have you done with my child?” is a common joke parents make when their children start exerting their individuality. To accomplish the healthy separation process of development, children test boundaries to become separate individuals. These changes are particularly evident during toddlerhood and again during adolescence, as any parent may attest. Although teenage drama inevitably affects the entire family, having a clear idea of typical behavior and ways to respond helps everyone through the process as unscathed as possible.

What causes personality changes?

Personality is the culmination of biological, psychological and external factors that determine perception and response to events. Thus, certain aspects of a teenager’s personality might be evident in some situations and not in others. The debate over whether or not personality changes over time is an old and still ongoing one. However, three important conclusions emerged from reviewing recent genetic and behavioral research: 1) About half of personality is determined by innate characteristics (nature) and half through environmental influences (nurture); 2) Personality traits and associated behaviors can change over time; 3) Sudden personality changes are not typical and usually occur as a result of substance abuse, disease process or a very traumatic experience. However, because changes during adolescence occur so rapidly, it might be difficult to ascertain what exactly is happening.

Traits and facets of personality

Personality traits are generally defined according to field of application and associated theoretical framework. One popular personality theory described by McCrae and Costa is known as the “Big Five,” which describes the five traits that comprise personality to include openness, conscientiousness, extraversion, agreeableness and neuroticism. Each of these five traits has defining facets that have been shown to predict behavior and determine suitability for vocational assessment. The facets of each trait are measured along a continuum. These traits and corresponding facets are as follows in the form of the mnemonic “OCEAN”:

Openness: Intellect and openness

Conscientiousness: Industriousness and orderliness

Extraversion: Enthusiasm and assertiveness

Agreeableness: Compassion and politeness

Neuroticism: Volatility and withdrawal

The “Big Five” theory is just one approach to personality assessment. This approach has resulted in multiple psychometric assessment tools of various length and depth that are used primarily in vocational assessment and selection. Like most theories, the “Big Five” has its limitations and critiques, but does offer a starting point from which to consider the concept of personality.

What teen behavior is typical and what requires attention?

Though people in general demonstrate some level of all of these traits, most demonstrate each facet in different degrees and intensity levels. Some examples of behavior typically seen during adolescence for each of the “Big Five,” as well as some that warrant attention are shown in the table below.

Personality Trait Trait Facets Typical teen behavior Behavior requiring attention
Openness Intellect and openness Increased need for independent problem-solving; needs more privacy Sudden drop in grades; withdraws from family and/or friends
Conscientiousness Industriousness and orderliness Needs constant reminders; messiness Obsessive or compulsive behavior; neglected personal hygiene
Extraversion Enthusiasm and assertiveness Absence of enthusiasm;  stubbornness; changes in tastes (food, clothing, activities) Anhedonia (loss of pleasure in most things); defiance, irresponsibility
Agreeableness Compassion and politeness Disagreeableness; rudeness, disrespect Discipline problems outside of the home; encounters with law enforcement
Neuroticism Volatility and withdrawal Temper outbursts, moodiness Physical violence, road rage, substance abuse

Adolescence is a time for rapid change and renegotiation of the unspoken rules of engagement. New and different behaviors may evolve that concern or confuse family members. Sometimes teens themselves don’t understand why their own behavior is changing. As a result, teens need supportive adults to guide them through this challenging phase of development. Part of providing guidance is the ability to detect when adolescents need help, as teens are rarely able to recognize or verbalize their level of distress.

A few general points to remember regarding teenage personality changes:

  • Maintain open dialogue and eliminate unspoken tension.
  • Sudden, dramatic personality changes always warrant attention. Medical problems, substance use and traumatic abuse must be ruled out.
  • Parents should trust their own instinct regardless of others’ opinions.
  • Address behavior with consequences affecting the teen’s future.
  • New, effective treatments are available for adolescents struggling with behavioral health problems, underlying mental illness or substance use disorders.


Adolescence can be an exciting time for teens and their families. Teens need support and guidance through this difficult time. Changes in behavior are both common and necessary, but sometimes such changes can be a sign of serious underlying issues. Early intervention has been shown to improve long-term outcomes and may prevent violence or suicide. Mental health treatment can also improve communication among family members, giving teens the security and confidence they need to develop into happy, healthy, functional adults.

White River Academy is a boarding school and treatment center for boys aged 12 to 17 who are recovering from trauma, substance abuse or co-occurring mental illness. At the White River Academy, the faculty and staff recognize the unique personality of all residents, and strive to help each boy maximize his potential based on his special gifts and challenges. For more information, please call 866-520-0905 to speak to one of our experienced advisors.

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