What causes personality change?

Sometimes, personality change is a normal part of development. It can also be the result of deliberate effort or therapy. Sometimes, however, personality change is unexpected, unwanted, or not controlled. In these cases, it may be related to an underlying mental illness or damage to the brain.

Mental illness causes of personality change

Personality change may be caused by many different mental illnesses including:

  • Anxiety disorders such as obsessive compulsive disorder and post-traumatic stress disorder
  • Borderline personality disorder (condition characterized by unstable relationships)
  • Dementia (including Alzheimer’s disease)
  • Schizophrenia

Other causes of personality change

Personality change can also be caused by other conditions or events including:

  • Brain damage or tumor
  • Certain medications
  • Deliberate effort
  • Drug or alcohol abuse
  • Exposure to toxic substances or poisons
  • Head injury
  • Infection
  • Major life changes
  • Stress
  • Surgery

Serious or life-threatening causes of personality change

In some cases, personality change may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:

  • Brain tumor
  • Elevated cerebrospinal fluid pressure
  • Intracranial hemorrhage
  • Severe infection
  • Stroke
  • Traumatic brain injury

    Questions for diagnosing the cause of personality change

    To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your personality change including:

    • When did you first notice your personality change?
    • Do you have any other symptoms?
    • Have you been ill recently?
    • Have you had a recent injury?
    • Have you experienced any major life events recently?
    • Do you have any diagnosed mental illnesses?
    • Do you have a family history of mental illness?
    • What medications are you taking?

    What are the potential complications of personality change?

    Personality change can be normal, and in some cases may even be the positive result of your deliberate effort or the result of therapy. In other cases, however, personality change is unwanted, unexpected, or uncontrollable. In these situations, personality change may be the result of brain damage or infection, or a mental disorder.

    Because spontaneous personality change can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

    • Absenteeism from work or school
    • Alcohol or drug abuse
    • Depression
    • Development of mental illness
    • Inability to perform daily activities
    • Loss of employment
    • Loss of relationships
    • Paralysis
    • Social isolation
    • Spread of infection
    • Tumor progression


    1. Borderline personality disorder. National Institute of Mental Health. http://www.nimh.nih.gov/health/topics/borderline-personality-disorder/index.shtml.
    2. Personality disorders. PubMed Health, a service of the NLM from the NIH. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001935/
    3. Lieb K, Zanarini MC, Schmahl C, et al. Borderline personality disorder. Lancet 2004; 364:453.

    What is personality change?

    Personality change refers to a shift in the way you think, act or feel. It may be noticeable only to you, or it may be evident to people close to you.

    Gradual personality changes can be normal as you age. It is also normal for you to have changing behaviors or feelings based on your mood, but these changes are temporary and can usually be attributed to a specific event. A sudden, ... Read more about personality changeintroduction


    What other symptoms might occur with personality change?

    Personality change may accompany other symptoms, which vary depending on the underlying disease, disorder or condition. Symptoms that frequently affect the brain may also involve other body systems.

    Mental illness symptoms that may occur along with personality change

    Personality change may accompany other symptoms that result from an underlying mental illness including:... Read more about personality changesymptoms

    Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Sep 20, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

    This Article is Filed Under: Mental Health and Behavior