Definition of Behavior - unusual or strange:

Unusual or strange behavior involves performing actions that are not normal for the person.

Considerations:

Unusual or strange behavior may include:

• Loss of memory that continues over time or gets worse
• Loss of the ability to concentrate and perform other mental tasks

Common Causes:

There are many causes of unusual or strange behavior, including medical and psychiatric illnesses. Two of the more common medical causes are:

• Delirium -- Sudden or quick onset of reduced consciousness, awareness, perception, or thought that may be a symptom of a medical illness such as brain or mental dysfunction
• Dementia -- Chronic, worsening loss of cognitive function that occurs with brain disorders

Psychiatric illnesses that are often associated with unusual or strange behavior include:

• Anxiety disorder
• Bipolar disorder
• Depression
• Psychosis
• Schizophrenia

Possible causes of strange behavior in older people include:

• Alcohol consumption in excess
• Alzheimer's disease
• Chronic exposure to cold (hypothermia)
• Dehydration
• Hypoglycemia
• Electrolyte abnormality
• Emotional problems (depression or feeling useless)
• Head injury (subdural hematoma)
• Heart attack, pulmonary embolism, stroke
• Infection (including pneumonia, gastroenteritis, urinary tract infection)
• Malnutrition (particularly vitamin B12 and thiamine deficiency)
• Medications (sleeping pills, pain relievers)
• Thyroid disorders (either underactive or overactive)
• Unfamiliar surroundings

Possible causes in people of all ages include:

• Diseases affecting the nervous system (neurological diseases)
• Recreational drugs (such as amphetamines and cocaine)
• Environmental hazards
• Low or high thyroid function
• Non-neurological diseases, especially those with fever (for example, pneumonia)
• Side effects of medications

Home Care:

A doctor should evaluate any unusual behaviors or personality changes. Treatments are based on the following causes of strange behavior:

• Alzheimer's disease -- medications, sympathetic care, occupational therapy, family support
• Brain tumor, head injury, stroke, infection, fever, or pneumonia -- seek immediate medical attention
• Emotional or psychiatric problems -- support, talk therapy, and medications
• Environmental causes -- change the environment or change environments
• Excess alcohol -- stop drinking (abstinence)
• Huntington's disease -- supportive care
• Hypothermia -- warmth (rewarming should be carefully monitored)
• Illicit drug use -- stop taking the drug and seek a doctor's advice for withdrawal symptoms
• Low thyroid function -- see your health care provider about thyroid hormone replacement treatment
• Malnutrition -- medical exam, followed by proper diet and vitamin supplements
• Medication -- ask the doctor about adjusting the dosage, changing medications, or stopping them
• Surgery -- this is usually temporary, but avoid long-term use of sedatives and painkillers

Call your health care provider if:

Schedule an appointment with your regular health care provider or a doctor who treats disorders of the nervous system (neurologist) if:

• The unusual or strange behavior is severe, long-term, unexplained, or is affecting your life
• You have dementia or delirium

What to expect at your health care provider's office:

The health care provider will perform a physical examination and will take a medical history. The physical examination will probably include a detailed evaluation of the nervous system (neurological evaluation).

Medical history questions may include:

• What unusual behaviors are present?
• How much is your lifestyle affected?
• Can you eat, dress, and perform other everyday activities?
• When did the unusual behavior begin?
• Is it getting worse, better, or staying about the same?
• How fast is the behavior changing?
• What other symptoms are present?

The following tests may be performed:

• Blood tests
• CT scan or MRI of the head
• Electroencephalogram (EEG)
• Mental status test
• Neuropsychological testing
• Urine tests