Personality Change Due To Another Medical Condition

A number of medical conditions can cause personality changes. Along with the few listed above, personality changes can be caused by:

• A cerebrovascular accident
• Anoxic brain injury
• Focal radiation
• Encephalitis/vasculitis
• Wilson disease
• Epilepsy
• Neurosyphilis
• Heavy metal poisoning
• Chemotherapy
• HIV disease
• CNS neoplasms
• Personality disorders

Researchers are still learning more about how a TBI is linked to medical personality change (MPC) in adults. Research suggests that a TBI causes MPC in 20-48% of patients, but in adults, personality change hasn’t been linked to a specific injury severity, age of occurrence, or time since the injury occurred. However, in children, the severity of the injury tends to be related to a personality change. In one study, 38% of children who experienced a severe TBI had persistent changes to their personalities. 

Scientists have identified a link between brain tumors and MPC in adults. Frontal and temporal lobe tumors may be more likely to cause a personality change and almost all patients who have a bilateral glioma experience a personality change. 

Symptoms that accompany a personality change due to another condition may depend on the original condition. Below are a few common medical conditions that can lead to a personality change.

Traumatic brain injury

A traumatic brain injury, or TBI, may cause a variety of symptoms including: 

• Irritability
• Emotional dysregulation
• Inappropriate laughter
• Rapid mood changes
• Sudden euphoria³
• Disinhibition
• Apathy
• Paranoia

Brain tumor

Common personality changes that occur when someone has a brain tumor include: 

• Hypersexuality
• Aggressive behavior
• Disinhibition
• Withdrawal
• Exaggerated mood changes
• Rage
• Depression 

Huntington’s disease

In patients with Huntington’s disease, nerve cells in the brain slowly break down and die, leading to mental, physical, and emotional changes. Personality changes related to the disease include: 

• Depression
• Aggression
• Anxiety
• Mania
• Disinhibition
• Altered sexuality

While not all patients experience the same symptoms, there are often predictable changes in behavior that they and their caregivers can expect. Prevalence of the changes may depend on the type and stage of the disease. 

Multiple sclerosis

Researchers have identified three primary disorders and symptoms associated with MS: depression, euphoria, and pathological laughing or crying. In addition, personality disorders are commonly connected to multiple sclerosis, which may cause personality changes. Researchers believe a frontal lobe syndrome may be a cause of personality changes with MS, as well. 

Urinary tract infection

Urinary tract infections are more common among older adults. These infections can cause delirium in the elderly and people with dementia, with changes including agitation, increased confusion, or withdrawal.

Thyroid disease

Hypothyroidism, a condition where the thyroid does not make enough of the thyroid hormone,⁴ has been linked to:

• Forgetfulness
• Lethargy
• Rapid and exaggerated mood changes
• Delirium

Hyperthyroidism occurs when the thyroid gland produces too much of the thyroid hormone. It can cause a variety of symptoms, including mood swings, and symptoms may be incorrectly interpreted as depression or dementia.

Treatment of personality change due to another medical condition typically involves treating the underlying condition. Treatment could include medication, surgery, and/or a variety of therapy options.

Medication

Sometimes, a personality change due to another medical condition can be resolved with a medication that treats the condition. For example, both hypothyroidism and hyperthyroidism can cause mood changes, such as depression, anxiety, mood swings, and even short-term memory issues. However, medication can often be used to help level your thyroid hormones and ultimately restore your original personality characteristics. 

A few conditions that cause personality changes that cannot be cured, include Huntington’s disease and Alzheimer’s. In those cases, a medical professional may recommend treatment that decreases the severity of the symptoms and preserves the quality of life for the patient. For instance, medication may be used to treat depression and other psychiatric disorders caused by Huntington’s disease.

It is important to consult with a doctor or medical professional before beginning or changing any medication plan. The information provided in this article is not intended as medical advice; please consult a qualified healthcare professional for personalized guidance.

Other treatment options 

Some medical conditions, such as brain tumors, will likely be treated through a mixture of surgery, radiation, and chemotherapy based on the oncologist’s recommendations. Multiple sclerosis may be treated by a variety of therapies, including plasma exchange. 

Self-care

Self-care can be a crucial aspect of caring for your mental health. The National Institute of Mental Health offers a few self-care suggestions that may help you take better care of both your mental health and your physical health, including the following: 

• Engage in regular exercise. 
• Eat nutritious, regular meals. 
• Stay hydrated with water and limit caffeinated drinks.
• Prioritize sleep by following a schedule and limiting blue light exposure before bed.
• Stay connected with family and friends who can offer their support.
• Practice gratitude by reflecting on the things for which you are thankful.
• Prioritize what needs to get done and practice saying no when you begin to feel overwhelmed. 

Turning to a therapist when you experience personality change due to another medical condition may better equip you to handle the unexpected changes in yourself. While these personality changes may seem out of your control at times, working with a therapist may help you acquire healthy coping and de-escalation skills. A therapist can also help if someone you love has had a personality change and you’re not sure how to cope with it.

Depending on your condition, you may want to choose a general or specialized therapist. While almost all professionals are equipped to work with patients experiencing anxiety and depression, some may have specialized experience to help those who have experienced a TBI or have developed PTSD. Consider asking your primary care physician for a referral or utilize online providers such as BetterHelp.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) also contains information about all diagnosable mental health conditions, including personality change due to another medical condition. 

For help with substance use, contact SAMHSA’s National Helpline at 1-800-662-HELP (4357).

Please see our Get Help Now page for more immediate resources.

Apathy is a common personality change caused by another medical condition. Approximately 45% to 50% of people with a severe traumatic brain injury (TBI) experience apathetic personality change, which can result in poor rehabilitation outcomes and difficulty with social reintegration. Research shows that caregivers may maximize stimulation, strongly encourage patients to participate in enjoyable activities, and provide verbal cues and checklists. 

Another study looked at a medication for Huntington’s disease. While the disease involves both physical and mental decline, cognitive and behavioral changes can precede motor deficits by up to 15 years. Researchers found that treatment with cariprazine during the early stages of Huntington’s disease led to improvement in apathy, cognitive function, and depressed mood.

Here are some key statistics on personality change due to another medical condition. 

• Between 8% to 67% of people with a brain tumor will also experience a medical personality change. However, it can be challenging to distinguish the medical personality change from the changes caused by surgery, chemotherapy, and radiation. 
• Common chronic⁵ conditions including cancer, hypertension, heart disease, stroke, respiratory disease, and arthritis have also been shown to cause personality changes. Researchers found that these conditions decrease patients’ extraversion, emotional stability, and conscientiousness. 
• Approximately 40% of people who experience a traumatic brain injury may have severe trouble controlling their anger, which can have a lasting impact on their ability to maintain a job and invest in their relationships with others.
• Often, a personality change due to a medical condition includes symptoms of depression or anxiety. While it’s still necessary to treat the original condition causing the changes, online therapy can significantly improve symptoms of depression and anxiety within 8 weeks. Even a year after therapy is complete, individuals may continue to see improvement.