Does epilepsy predispose patients to particular psychiatric illnesses or behavioral problems?
The relationship between behavioral conditions and epilepsy has long been controversial. Until the early 20th century, seizures were often considered a form of psychopathology and people with epilepsy were routinely confined to asylums. Perhaps in response, some more recent advocates for the epilepsy community have argued that there is no increased risk of psychiatric or behavioral symptoms among epilepsy patients.
Data from a wealth of clinical and research studies now support a balanced position, concluding that people with epilepsy are at higher risk for certain types of psychiatric disorders and behavioral symptoms, although most do not develop severe psychiatric illness or maladaptive behavior.
For example, depressive disorders are more likely to occur among people with epilepsy than in the general population. A recent survey carried out in 185,000 households revealed that 29% of people with epilepsy had experienced one episode of major depression, compared to 8% of people reported to be healthy and 16% of people with asthma or diabetes. Depressive disorders are much more frequent among people with poorly controlled seizures than among people whose seizures have been controlled with medication.
Studies carried out in the 1990s revealed that the relationship between psychiatric disorders and epilepsy may be complex and may, in fact, be bi-directional rather than uni-directional. For example, there is clear evidence that not only are patients with epilepsy at higher risk of developing depression, but patients with depression have a four- to six-fold higher risk of developing epilepsy. Clinicians who care for patients with epilepsy must consider the possibility of epilepsy-related psychiatric symptoms, since specialized evaluation and treatment may be necessary.
A significant number of people have been erroneously diagnosed with epilepsy who in fact do not suffer from an epileptic seizure disorder. These patients present recurrent episodes that clinically mimic epileptic seizures, but in fact they are experiencing nonepileptic seizures, covered in more detail elsewhere.
Nonepileptic seizures may be of psychogenic origin or may represent a variety of organic conditions such as:
- syncope (fainting spell)
- a form of sleep disorders
- panic attacks
- a type of movement disorder
Until the correct diagnosis of psychogenic nonepileptic seizures is established, most of these patients are considered to have intractable epilepsy and are treated with high doses of antiepileptic medications. The correct diagnosis often is established only after they are referred to an epilepsy center to be evaluated for epilepsy surgery. In fact, one out of every four to five patients referred to an epilepsy center with a diagnosis of intractable epilepsy suffers from nonepileptic seizures, most of which are psychogenic.
A certain percentage of patients with psychogenic nonepileptic seizures also may suffer from epileptic seizures, or may have had epileptic seizures in the past, which may be under control with their antiepileptic medication. For patients with both epileptic and nonepileptic seizures, it is essential to distinguish between the two types so the epileptic seizures can be treated with antiepileptic medication, while the nonepileptic seizures receive other appropriate treatment.
What psychiatric conditions are most common?
Depressive, anxiety, psychotic, and attention deficit disorders are more common in people with epilepsy than in the general population. This table compares the prevalence rates of these psychiatric disorders between people with epilepsy and the general population:
|Psychiatric Disorder||Prevalence Rates|
|People with epilepsy||General population|
|Depression||11 - 60%||3.3%: Dysthymia
4.9 - 17%: Major depression
|Psychosis||2 - 9%||1%: Schizophrenia
0.2%: Schizophreniform disorder
|Generalized Anxiety Disorders||15 - 25%||5 - 7%|
|Panic Disorder||5 - 21%||0.5 - 3%|
|ADHD||12 - 37%||4 - 12%|
What are the causes of psychiatric complications in epilepsy?
Evidence supports a neurobiologic basis for many of these conditions, but other predisposing factors may play a major role in the development or severity of psychiatric complications in some patients:
- The person's environment while growing up might have restricted social development and intellectual functioning. Elements of this environment might include parental overprotectiveness, strict medication regimens, limitations on participation in sports or other activities, and repeated seizures.
- Social stigma, restrictions, and biases (both while growing up and in adulthood) may adversely affect self-esteem and limit involvement in academics, employment, and social activities.
- Neurologic disorders associated with the seizure disorder may produce symptoms other than seizures that make it difficult to negotiate everyday life.
- The introduction of antiepileptic drugs (AEDs) with negative psychotropic properties is a well known cause of psychiatric symptoms. In addition, discontinuation of AEDs with mood stabilizing properties, such as carbamazepine (Tegretol, Carbatrol), valproic acid (Depakote), and lamotrigine (Lamictal) may unmask an underlying mood disorder.
- Genetic predisposition for psychiatric disorders such as mood disorders, panic disorder, and attention deficit disorder can facilitate their occurrence in the presence of epileptic seizure disorders.
Adapted from: Holzer JC and Bear DM. Psychiatric considerations in patients with epilepsy. In: Schachter SC, Schomer DL, eds. The comprehensive evaluation and treatment of epilepsy. San Diego, CA: Academic Press; 1997. p. 131-148. With permission from Elsevier (www.elsevier.com).