Behavior - unusual or strange

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

Possible causes of strange behavior in older people include:

• Alcohol in excess
• Alzheimer's disease
• Chronic exposure to cold (hypothermia)
• Dehydration
• 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
• Thyroid disorders (either underactive or overactive)
• Unfamiliar surroundings

Possible causes in people of all ages include:

• Anxiety, emotional problems
• Diseases affecting the nervous system (neurological diseases)
• Illicit drug use (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 antidepressants, such as Prozac
• Side effects of medication for attention deficit disorder, such as Ritalin

A doctor should check any unusual behaviors or personality changes. Treatments are based on the following causes of delirium:

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

Contact 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