Epilepsy includes a spectrum of seizure disorders caused by abnormal electrical activity in the brain. Approximately 1 percent of the general population has epilepsy, but having a related condition may put you at greater risk. When two or more conditions occur at the same time — such as epilepsy and depression — the conditions are said to be comorbid.
Sometimes, a comorbid disorder occurs alongside epilepsy as a consequence of epilepsy. Other times, a preexisting condition can increase the risk of later developing epilepsy. Epilepsy and comorbid conditions often share underlying biological mechanisms that can increase the risk of either condition.
Managing two conditions at the same time can affect your quality of life. If you have epilepsy, it may help to understand your risk of related conditions so you can work with your doctor or health care team to help prevent or treat the other conditions. Here’s what to know about the comorbidities of epilepsy.
Neurological disorders are brain-related conditions. Abnormalities in sodium channels, which help regulate electrical activity in the brain, may be a shared mechanism in many neurological disorders that occur alongside epilepsy.
Alzheimer’s disease is a disease of cognitive decline, brain atrophy, and dementia. Research has found that people who have Alzheimer's disease are at an increased risk of seizures or epilepsy. Approximately 10 percent to 22 percent of people with Alzheimer’s will experience at least one seizure, typically beginning in the later stages of Alzheimer’s disease.
Research in mice has shown that high levels of beta-amyloid protein in the brain (a characteristic trait of Alzheimer’s disease) can cause seizure activity. This finding has led experts to believe that Alzheimer’s disease may be a risk factor for epilepsy development.
Migraines cause intense headaches accompanied by sensitivity to light, nausea, and other symptoms. Headaches (including migraines) appear at a higher rate in people with epilepsy (52 percent of men and 57 percent of women) compared to the general population (16 percent of men and 28 percent of women). Migraines may share common genetic roots with epilepsy.
Viral encephalitis is an infection of the brain that causes inflammation. Like brain tumors, encephalitis can cause epilepsy. The frequency of seizures in cases of encephalitis ranges from 7 percent to 46 percent.
Cerebrovascular disease refers to a variety of conditions that disrupt blood flow or damage blood vessels within the brain. Problems with blood flow can lead to stroke. According to the Epilepsy Foundation, strokes are the most common cause of epilepsy in the elderly and account for 22 percent to 69 percent of seizures in this age group.
Several psychiatric and cognitive disorders are related to epilepsy, including attention deficit hyperactivity disorder (ADHD), depression, anxiety, autism, and psychosis.
ADHD is a disorder of attention and impulsiveness that affects children and adults. ADHD has been shown to occur at a higher rate in children with epilepsy than in the general population. Among all children, rates of ADHD are approximately 9 percent. Research has shown that the rate of ADHD in children with epilepsy, however, is between 27 percent and 40 percent, making ADHD one of the most common psychiatric comorbidities of childhood epilepsy.
Depression is a mood disorder related to feelings of sadness. Overall, people with epilepsy tend to have depression at higher rates than people without epilepsy. Changes in the brain chemical messengers (neurotransmitters) norepinephrine and serotonin may underlie features of both depression and epilepsy.
Epilepsy may result in the development of anxiety, a psychiatric condition that causes excessive worry and fear. Anxiety has been reported to occur in approximately 23 percent of people with epilepsy, compared to 11 percent in the general population. Because anxiety medications can be used to treat epilepsy and antiepileptic drugs can be used for anxiety, scientists believe that the conditions also share similar brain biology underpinnings.
Autism, or autism spectrum disorder, is a developmental disorder of communication. Neurotypical children (children without autism) experience epilepsy rates around 1 percent to 2 percent. However, in children with autism, the rate of epilepsy is around 30 percent. This relationship is likely due to shared genetic risk factors, as research shows that autism and epilepsy share 20 genes.
Psychosis, or when a person loses contact from reality and experiences delusions, can be a symptom of epilepsy. Research shows that people with epilepsy are at eight times the risk of psychosis than the general population.
Insomnia and sleep apnea are two sleep disorders that are associated with epilepsy.
Sleep apnea, or obstructive sleep apnea, is a serious condition in which a person repeatedly stops breathing while sleeping. According to one study, about 30 percent of individuals with epilepsy also experienced sleep apnea. The typical treatment for sleep apnea is continuous positive airway pressure (CPAP). CPAP use has also been shown to reduce seizure activity.
Autoimmune disorders also frequently occur in the context of epilepsy. The International League Against Epilepsy classification system suggests that there may be an immune component of epilepsy that could explain the association between epilepsy and some autoimmune disorders.
Doctors and researchers have noticed a relationship between type 1 diabetes mellitus (a condition in which the pancreas does not produce enough insulin) and epilepsy. Studies show that approximately 25 percent of people with diabetes also experience epilepsy, whereas epilepsy occurs in approximately 1 percent of the general population. Some scientists believe that changes in brain metabolism related to low blood sugar levels may be the link between these two conditions.
A thyroid disorder is a condition involving the dysregulation of thyroid hormones, which contribute to many functions in the body. Thyroid conditions and epilepsy have both been linked to mitochondrial dysfunction and oxidative stress. Some research suggests that thyroid disorders may lead to the development of epilepsy.
A chronic weakness of skeletal muscles known as myasthenia gravis has also been observed in people with epilepsy. One study shows that about 3 percent of people with epilepsy also experience myasthenia gravis, a condition that affects less than 1 percent of the general population.
Multiple sclerosis (MS) is an autoimmune disease that attacks the brain and spinal cord. This condition occurs more frequently than by chance in people with epilepsy. Some researchers suspect that MS lesions in the brain can act as a focal point for an epileptic seizure.
Lupus is an autoimmune disease involving inflammation and pain in connective tissues. Research shows that people with lupus are at nearly a sixfold risk of developing epilepsy compared to people without lupus.
Other medical conditions have also been shown to be comorbid with epilepsy. These disorders related to epilepsy include:
Your doctor can help you understand your risk factors for developing related conditions. The doctor can also recommend steps to manage or lower your risk. Always make sure your health care provider is aware of every medication you are taking for any condition, whether the medication is available over the counter or by prescription, including any vitamins or herbal supplements. Some medications can cause dangerous interactions. Open communication with your doctor ensures you can be partners in decision-making about your health.