Skip to content
My WebMD Sign In, Sign Up

Mental Health Center

Font Size

Changes in Behavior

A change in how a person acts is called altered behavior. A change may include:

  • Confusion.
  • Disorientation to time and place.
  • Unusually aggressive or combative behavior.
  • Lethargy, unexplained sleepiness, or the inability to arouse a person from sleep.

Altered behavior can be caused by conditions or substances that may affect the brain, such as:

  • Prescription and nonprescription medicine.
  • Drug and alcohol abuse or withdrawal.
  • Electrolyte imbalances.
  • Exposure to toxins, such as carbon monoxide, arsenic, or lead.
  • Lack of oxygen to the brain.
  • Head injury.
  • Seizure.
  • Abnormally high blood sugar (hyperglycemia) or abnormally low blood sugar (hypoglycemia).
  • Infection, especially in older adults.
  • Mental health problems, such as anxiety disorders, depression, or psychosis.
  • Blockages in the blood vessels in the brain, such as in a stroke.
  • Bleeding in the brain from a head injury or stroke.
  • Destruction of brain tissue by a tumor.
  • Pressure on brain tissue by a tumor or swelling.

Changes in behavior may be sudden, such as those caused by a stroke or head injury. Or they may be gradual, such as those caused by a tumor or swelling in the brain.

ByHealthwise Staff
Primary Medical ReviewerWilliam H. Blahd, Jr., MD, FACEP - Emergency Medicine
Specialist Medical ReviewerH. Michael O'Connor, MD - Emergency Medicine
Last RevisedSeptember 1, 2011

WebMD Medical Reference from Healthwise

Last Updated: September 01, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Today on WebMD

Hands breaking pencil in frustration
Woman looking out window
woman standing behind curtains
Pet scan depression
Woman standing in grass field barefoot, wind blowi
Plate of half eaten cakes
mother kissing newborn
Woman multitasking
colored pencils
Woman relaxing with a dog

WebMD Special Sections