What Causes Personality Change?

Medically reviewed by George Krucik, MD, MBA

Unusual or strange behavior is behavior that is not appropriate to the circumstances. It occurs when a person is unnaturally moody, aggressive, euphoric, or mild-tempered. Fluctuations in mood from time to time are normal. However, unusual... Read More

What Characterizes Strange or Unusual Behavior?

Unusual or strange behavior is behavior that is not appropriate to the circumstances. It occurs when a person is unnaturally moody, aggressive, euphoric, or mild-tempered. Fluctuations in mood from time to time are normal. However, unusual reactions to events may be a sign of a medical or mental disorder. Some examples are being happy to hear tragic news or being nonchalant in situations that would normally cause stress or aggravation.

When Is Unusual Behavior a Cause for Concern?

Grief, bad news, and disappointment can cause a normally happy person to become downtrodden. Sometimes, a person’s mood can be altered for weeks or months after hearing devastating news.

However, some people experience unusual or strange behavior for years. This usually occurs if they have been through a traumatic change or witnessed an unpleasant event.

These behavioral changes may be caused by a mental disorder, such as:

  • Anxiety: Anxiety occurs when a person feels nervous or uneasy about a situation. It is normal to experience some anxiety, but when it occurs on a regular basis without provocation, it may be a sign of generalized anxiety disorder.
  • Panic attacks: Panic attacks are periods of extreme fear. Sometimes, the fear seems to be irrational. Such situations include a person having a panic attack when seeing an elevator or speaking in public.
  • Posttraumatic stress disorder: Posttraumatic stress disorder, also called PTSD, is a mental condition marked by extreme fear, flashbacks, and hallucinations. This condition is triggered by memories of trauma, such as a terrorist attack or car accident.
  • Bipolar disorder: Bipolar disorder causes a person to have extreme fluctuations in mood. Bipolar disorder is marked by a quick switch between being happy and being upset. The switch is often extreme, causing a person to act out when hearing disagreeable things.
  • Schizophrenia: Schizophrenia is a mental disorder that makes it difficult to think clearly, to have normal emotions, to behave normally in social situations, and to distinguish between what is real and what is not real.

Medical conditions that cause a fluctuation in hormone levels can also cause strange or unusual behavior. These conditions include:

  • menopause
  • premenstrual syndrome (PMS)
  • andropause (male menopause)
  • hyperthyroidism/hypothyroidism (an over- or under-active thyroid gland)

Medical emergencies can also cause strange or unusual behavior. These situations include:

  • heart attack
  • stroke
  • dehydration
  • malnutrition

When Is Unusual Behavior a Medical Emergency?

Look for the following signs to determine if strange or unusual behavior is an emergency situation:

  • weak pulse
  • clammy skin
  • rapid heart rate
  • rapid breathing
  • shallow breathing
  • low blood pressure
  • confusion
  • dizziness
  • lightheadedness
  • difficulty talking
  • shooting pains in the arms or legs
  • pain in the chest
  • visual changes

If you or a loved one experiences any of these symptoms, seek medical attention immediately. Do not drive yourself to a hospital. Call 911.

Diagnosing Unusual Behavior

If you’ve been experiencing unusual or strange behavior, speak to your doctor about it. Make sure to note

  • when the strange behavior began
  • what times of day you experience it
  • what triggers it
  • whether it happens after taking prescription medication (bring the prescription with you)
  • if you are taking drugs
  • if you’re using alcohol
  • if you have a history of mental disorders
  • if your family has a history of mental disorders
  • any other symptoms you may be experiencing
  • if you have any underlying medical conditions

The answers to these questions will be extremely helpful to your doctor. They will help him or her diagnose the cause of your unusual behavior. They will also assist him or her in determining whether your problem is a mental or medical issue.

The doctor may choose to run tests. These may include a complete blood count, glucose level test, hormone profile, and tests for infections. If you have no discernible medical condition, he or she will refer you to a mental health specialist.

Treating Unusual or Strange Behavior

Unusual or strange behavior caused by a medical condition, such as hypothyroidism, may subside once the condition is treated. However, in some cases, this symptom will not go away with treatment of the underlying condition. In this case, you must be treated separately using mood-altering medications.

If you have a hormonal imbalance, the strange behavior may subside after being prescribed medications to balance your hormones. Replacement estrogen, low-dose birth control pills, and progesterone injections are commonly prescribed medicines.

Mental health conditions may be treated with a combination of mood-altering medications and therapy. Doctors typically prescribe medications to treat conditions such as anxiety disorder, panic disorder, PTSD, and bipolar disorder. Psychotherapy, also called talk therapy, might also be recommended to help you learn to cope with stressful situations.

Medically reviewed by George Krucik, MD on Invalid DateWritten by April Kahn

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This feature is for informational purposes only and should not be used to diagnose. Please consult a healthcare professional if you have health concerns.

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