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Personality Change

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Last updated August 27, 2020

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Understand personality change symptoms, including 9 causes & common questions.

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Personality change symptoms

It is possible for a person to undergo a change in personality due to psychological events, such as suffering extreme shock or fear; but most cases of personality change are the direct result of physical damage to the brain from injury or some form of illness.

A change that is caused only by psychological reasons can usually be helped with appropriate medication and counseling. A change that is caused only by damage to the brain cannot be cured, but can be managed with medication, counseling, supportive care, and assistance with activities of daily living. Some changes in personality are a combination of both physical damage and the emotional reaction to it. Again, both psychological and medical help will be used to ease the symptoms and improve quality of life for the patient and for the caregivers.

Emotional personality change symptoms

Changes in personality related to the emotions may include:

  • Apathy: This is disinterest in life.
  • Depression: This is often accompanied by withdrawal from social situations.
  • Anxiety
  • Irritability: This can sometimes lead to aggression.
  • Rapid mood swings or emotional lability
  • Suicidal ideation

Memory and perception difficulties

Changes in personality may result in difficulties with memory and perception as well as:

  • Confusion
  • Forgetfulness
  • Loss of organizing ability
  • Difficulty recognizing certain emotions: This may be in yourself or in others.
  • Hallucinations: These may be visual (seeing things) or auditory (hearing things, such as voices).

Behavioral problems

Personality changes may manifest as behavioral problems, such as:

  • Loss of inhibition: Doing things that are not socially acceptable, such as approaching strangers, going into the wrong house, etc.
  • Altered sexuality: This means an increased or decreased sex drive with behavior that may be inappropriate.

Medication-related symptoms, such as chemotherapy

Personality changes may result due to certain medications, such as chemotherapy. These medications may also cause:

Are personality change symptoms serious?

The severity of your personality change is ultimately determined not only by the cause, but the impact it has on your life.

  • Not serious: A certain amount of forgetfulness is not unusual in an older person, especially after a long day or when very tired.
  • Moderately serious: Struggling to cope with traumatic brain injury or other personality-changing illness can cause severe and ongoing depression. If not treated, this can lead to substance abuse or suicide attempts.
  • Serious: A personality change that arises quite suddenly can be a sign of stroke or other serious illness.

Personality change causes

Traumatic brain injury (TBI)

Traumatic brain injuries can result in personality changes due to physical damage to the brain.

  • Bleeding into the brain: This can occur from spontaneous rupture of a blood vessel.
  • Loss of oxygen in the brain: This can be due to drowning, heart attack, carbon monoxide poisoning, or other forms of suffocation. Damage occurs after just minutes and will be evident once the person is conscious again.
  • Side effects of diabetes or issues with blood sugar: Insufficient blood glucose, often in diabetics, starves the brain of energy.
  • Infections: Viral and bacterial infections of the brain and spinal cord (meningitis) can cause serious damage to those tissues.
  • If you lost consciousness: Behavior and personality sometimes change following a hard blow to the head, especially if you lose consciousness.

Personality change questionnaire

Use our free symptom checker to find out what's causing your personality change.

Personality change symptom checker

Progressive disease affecting the brain

Diseases that gradually affect the brain may lead to personality changes of varying severity and onset.

  • Neurologic diseases: Most of these are genetic. These are known for producing profound changes in personality due to their powerful effect on the brain.
  • Aging and disease: Gradual loss of brain function due to aging combined with unknown factors can sometimes lead to severe disability.

Psychiatric illnesses

These illnesses are complex, although, diagnoses can usually be determined by professionals and consultation of the DSM 5, or the Diagnostic and Statistical Manual for Mental Disorders (5th edition). These illnesses can cause disturbing or inexplicable behavior due to chemical imbalances in the brain. Changes in behavior can also result, affecting sleep habits, food cravings or appetite, as well as sexual demeanor in addition to mood.

Normal aging

Normal aging can cause irritability, anger and frustration due to:

  • Hearing loss
  • Vision loss
  • Loss of mobility
  • Chronic pain

Rare and unusual causes

A brain tumor can cause loss of certain functions due to crowding and displacement of tissue, but personality change does not always happen.

9 conditions of personality change

This list does not constitute medical advice and may not accurately represent what you have.


Depression is a mental disorder in which a person feels constantly sad, hopeless, discouraged, and loses interest in activities and life on more days than not. These symptoms interfere with daily life, work, and friendships.

Rarity: Common

Top Symptoms: fatigue, depressed mood, headache, anxiety, irritability

Symptoms that always occur with depression: depressed mood

Urgency: Primary care doctor

Mild bipolar disorder i

Bipolar disorder is a common, lifelong mental health condition of variable severity that can run in families, characterized by episodes depression and mania that last for weeks or months. Symptoms often start in adolescence or young adulthood.

Mania is a state of elevated or irritable mood, with changes in behavior, such as decreased need for sleep, increased goal-directed and risky activities, and increased talkativeness. Depressive episodes in bipolar disorder are like major depression, characterized by low mood, loss of pleasure, and low energy. Mood episodes are separated by periods of remission with stable mood and minimal difficulties with daily function.

Treatment for bipolar disorder varies from person to person, depending on symptoms and other individual factors. It often consists of medications such as mood stabilizers and antipsychotics that help reduce extreme symptoms. Hospitalization may be recommended in acute episodes. Psychotherapy can also be helpful.

Rarity: Rare

Top Symptoms: fatigue, irritability, depressed mood, difficulty concentrating, trouble sleeping

Symptoms that always occur with mild bipolar disorder i: periods of feeling very energetic and needing little sleep

Urgency: Primary care doctor

Borderline personality disorder

Borderline personality disorder is a personality disorder, or a persistent abnormal behavior pattern manifesting during childhood or adolescence, involving unstable mood and relationships, unstable self-image, and recurrent self-harm or suicida...

Alzheimer's disease

Alzheimer's disease is a progressive neurological disorder that slowly destroys memory and the ability to think clearly. As symptoms worsen, patients are often unable to perform basic tasks.

Rarity: Common

Top Symptoms: trouble sleeping, forgetfulness, anxiety, aggression or confusion, anxiety, irritability, depressed mood

Symptoms that always occur with alzheimer's disease:forgetfulness, anxiety, aggression or confusion

Urgency: Primary care doctor

Brain tumor or mass

In medical terms, "mass" and "tumor" mean the same thing: the unexplained, out-of-place growth of tissue anywhere in the body, including the brain.

The cause of any sort of brain tumor is unknown. Some originate in the brain, while others spread from cancers growing in other parts of the body.

Symptoms may include increasing headaches; nausea and vomiting; blurred or double vision; loss of sensation in an arm or leg; loss of balance; confusion; speech difficulties; or seizures.

If symptoms persist, it is important to see a medical provider so that any treatment can begin as soon as possible.

Diagnosis is made through neurological examination, CT scan, and/or MRI.

If the mass or tumor is found to be benign, that means it is not cancer and not harmful. It may or may not be treated.

If it is malignant, that means it is cancer and must be treated. This will involve some combination of surgery, radiation therapy, and chemotherapy, followed by specialized therapy to help with recovery.

Rarity: Rare

Top Symptoms: fatigue, headache, nausea, loss of appetite, irritability

Symptoms that always occur with brain tumor or mass: focal neurological symptoms

Urgency: In-person visit

Low calcium level

Hypocalcemia is a condition where there is not enough calcium in the blood. Calcium is a mineral contained in the blood, which helps the heart and other muscles function properly, and is needed to maintain strong teeth and bones.

Rarity: Rare

Top Symptoms: fatigue, shortness of breath, irritability, general numbness, tingling foot

Urgency: Primary care doctor

Viral encephalitis

Encephalitis is irritation and swelling (inflammation) of the brain, most often due to viral infections. Encephalitis caused by the herpes simplex virus is the leading cause. Several other causes of encephalitis (St. Louis, California, Japanese and Eastern Equine encephalitis infections) are transmitted by bites from an infected mosquito.

Rarity: Rare

Top Symptoms: fatigue, being severely ill, loss of appetite, new headache, vomiting

Symptoms that always occur with viral encephalitis: being severely ill

Urgency: Hospital emergency room

Cerebral paragonimiasis

Paragonimiasis, or lung fluke disease, is caused by infection with a number of species of trematodes (flat worms) belonging to the genus Paragonimus. These organisms mostly inhabit areas in East Asia, and travel to those areas can increase the risk of contracting this disease. The larva (early life stage of the worm) enters the body through the intestine and travels up to the brain, where it develops into an adult form.

Personality change questionnaire

Use our free symptom checker to find out what's causing your personality change.

Personality change symptom checker

Rarity: Ultra rare

Top Symptoms: cough, new headache, nausea or vomiting, fever, vision changes

Urgency: Hospital emergency room

Tertiary phase of syphilis infection

Syphilis is a common sexually trasmitted infection (STI). Late phase, or tertiary, syphilis is uncommon, as it occurs years to decades after initial exposure to the infection. It is the most progressed and serious stage of the disease. Late phase syphilis infection can lead to loss of function of multiple organ systems, especially the nervous system, the heart and blood vessels, and the liver.

Rarity: Rare

Top Symptoms: joint pain, fatigue, irritability, numbness or tingling sensations in skin, dizziness

Urgency: Primary care doctor

Personality change treatments and relief

When to see a doctor

You should visit a physician to address the following.

  • Any ongoing behavior that seems unusual for yourself or a person in question: Especially if it is inappropriate, baffling, or dangerous.
  • Support: Ask your medical provider about advice and support for caregivers, so that the caregivers do not become exhausted and overstressed while helping a partner or parent with personality change.
  • Psych evaluation: Ask your medical provider about a referral to a psychologist, particularly one who can help both the patient and the caregiver cope with the symptoms of personality change and with the difficulties of the illness that may be causing it.

When it is an emergency

Seek immediate personality change treatment in the emergency room or call 911 for the following.

  • Symptoms of bleeding into the brain (stroke) with severe headache, confusion, and loss of function on one side of the body
  • Extreme confusion and disorientation: Especially if the person is suffering from visual or audial hallucinations

Questions your doctor may ask about personality change

  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Are you feeling irritable (easily made upset)?
  • Are you feeling less alert than normal?
  • Are you experiencing a headache?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Share your story

Janeen has worked over eight years as a full-time medical transcriptionist, specializing in pain management and gynecologic oncology. She later began transcribing reports for hospital emergency rooms and acute care admissions. This background gave her a strong medical vocabulary as well as a heart for making medical information accessible to the average person, leading her to work as a medical writer. She began as a pre-veterinary medicine major at Texas State University.

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