A change in someone’s personality could be subtle and come on slowly, or dramatic and sudden. A person may seem more down, irritable or angry. Or they can be more activated or “hyper.” Someone can start to seem forgetful or be confused. Often these changes are noticed by family members.
Understanding the cause of personality changes can be complicated because several types of mental illnesses and medical illnesses may trigger them. It can be from depression, anxiety, or dementia. But it can also be caused by a concussion, a tumor, or even a urinary tract infection, especially in the elderly. Certain medications may also cause personality changes.
It’s important to talk with your doctor about any personality changes. Keeping a mood log—and tracking any physical symptoms you have—can help your doctor identify the cause and develop a treatment plan.
Pro Tip
There are many causes for personality changes, as well as many potential treatments. Your doctor will need your medical and psychiatric history to get a better handle on why this could be occurring. —Dr. Keerthan Somanath
3. Dementia (including Alzheimer’s disease)
Symptoms
- Cognitive decline (not due to delirium or another mental disorder)
- Forgetfulness
- Restless sleep
- Mood changes
- Anxiety
- Confusion
- Irritability
Dementia is a decline in cognitive abilities that affects your short-term memory, reasoning, language, and ability to focus. These deficits interfere with being able to carry out everyday activities. People with dementia often have behavioral and personality changes. They may be sad, anxious, or clingy.
Dementia is a progressive disease, which means it gets worse with time. There are three common types of dementia:
- Alzheimer’s disease. This creates plaques in the brain that cuts off nutrients to brain neurons. It’s the most common form of dementia. It mainly affects older adults, with symptoms often occurring between age 60 to 70.
- Vascular dementia. In this case, dementia is caused by blocking, narrowing, or damage to blood vessels in the brain, which can occur during a stroke or brain bleed.
- Frontotemporal dementia. This type of dementia is a progressive loss of nerve cells in the brain’s frontal and temporal lobes. Frontotemporal dementia occurs in people between age 45 to 65.
Pro Tip
A patient with frontotemporal dementia may say, “My family has been telling me I’m behaving differently. Specifically, that I’ve been saying things to people that I normally wouldn’t say.” A patient with depression who has become withdrawn may say, “I have been feeling down and depressed.” —Dr. Somanath
Treating dementia
While dementia cannot be cured, the symptoms can be temporarily managed with medication, lifestyle and behavioral changes, and social connection and support. Existing medications are somewhat controversial. Talk to your doctor to weigh the benefits and risks of any medications.
4. Urinary tract infection
Symptoms
- Pain when urinating
- Feeling like you always need to urinate (even if you just did)
- Foul-smelling urine
- Cloudy urine
- Confusion
- Agitation
A urinary tract infection, or UTI, occurs when bacteria invade the urinary system, including the bladder. In older adults, an untreated UTI can cause temporary personality changes such as confusion and agitation.
Usually, personality changes caused by a UTI come on suddenly and go away once the UTI is treated.
Treating a UTI
Your doctor will diagnose a UTI by taking a urine sample. A UTI is treated with antibiotics.
5. Post-concussion syndrome
Symptoms
- Headache
- Decreased concentration
- Memory problems
- Fatigue
- Irritability
- Vision problems
- Sleep disturbances
A concussion is a type of brain injury that damages brain cells and affects how your brain functions. This can lead to physical and personality changes. Your symptoms may last for a few days or a month, or they may linger for months or even years. This is called post-concussion syndrome (PCS).
There are several types of injuries that can lead to a concussion and PCS, including a car accident, a sports injury, or a fall. Older people are more likely to develop PCS following a concussion.
Treating PCS
Your doctor will diagnose PCS based on your symptom history and, in some cases, brain imaging tests. Treatment depends on the severity of your symptoms and the type of injury you have.
Lifestyle changes, such as getting more rest and limiting screen time, are recommended. You may also be referred to a specialist. For example, you may need to see a neurologist if you have problems like lack of concentration and headaches.
6. Brain tumor
Symptoms
- Headache
- Nausea
- Vomiting
- Slurred speech
- Blurry vision
- Confusion
- Personality changes
- Loss of balance
- Seizures
A brain tumor, or mass, is an abnormal growth of tissue in the brain. Many brain tumors are benign, while others are malignant. Some tumors form in the brain, while others occur when a cancer in another part of the body spreads to the brain.
Treating a brain tumor
If your doctor suspects a brain tumor, they will do a neurological exam and order imaging tests such as a CT scan or MRI. If the tumor is benign, it may or may not be treated depending on your symptoms.
Benign tumors can be removed surgically if necessary. If the tumor is malignant, it must be treated. Your doctor will recommend a combination of surgery, radiation therapy, and chemotherapy.
Other possible causes
Several other medical and psychiatric conditions can lead to changes in your personality. These include:
- Bacterial or viral encephalitis
- Low blood sugar
- Side effects of certain medications
- Psychotic disorders, such as schizophrenia or drug-induced psychosis
- Personality disorders, such as borderline personality disorder, which can cause impulsiveness, self-destructive behaviors, chronic feelings of emptiness, and extreme mood swings
- Aging
- Going through a stressful situation
