The International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE) define epilepsy as a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures and by the biologic, cognitive, psychological, and social consequences of this condition. This association may reflect the anatomical and neurobiological source of both epileptic seizures and the behavioral manifestations.
Antiepileptic drugs (AEDs) can play a role in the genesis of psychiatric symptoms; on the other hand, some psychotropic medications can lower the seizure threshold and provoke epileptic seizures.
Indeed, there is a general agreement that the incidence of neurobehavioral disorders is higher in patients with epilepsy than in the general population, although some authors argue that this apparent overrepresentation is due to sampling errors or inadequate control groups. Many, but not all, authors also accept the proposition that the link between neurobehavioral disorders and temporal lobe or complex partial epilepsy is particularly strong.
Factors in the relationship between epilepsy and behavioral disorders
Mechanisms for a relationship between epilepsy and behavioral disorders include the following:
Ictal neurophysiologic effects
Inhibition or hypometabolism surrounding the epileptic focus
Alteration of receptor sensitivity
Secondary endocrinologic alterations
Primary, independent psychiatric illness
Consequence of medical or surgical treatment
Consequence of psychosocial burden of epilepsy
Multiple interacting biologic and psychosocial factors determine the risk for the development of either schizophreniform psychoses or major depression in patients with epilepsy, and behavioral disorders in epilepsy have multiple risk factors and multifactorial etiologies.
Role of the neurologist in the psychiatric management of patients with epilepsy
As neurologists, we tend to focus on seizure control, and psychiatric comorbidities are often underestimated. Recognizing psychiatric manifestations is an area that needs improvement. Once symptoms are identified, the following questions arise
Are the symptoms related to the occurrence of seizures (preictal, ictal, postictal)?
Are the symptoms related to AEDs?
Is the onset of symptoms associated with the remission of seizures in patients who had previously failed to respond to AEDs?
Because of the phenomenology of epilepsy, the close association between epilepsy and psychiatry has a long history. The traditional approach to epilepsy care has been to focus on the seizures and their treatment. Concentrating only on the treatment of the seizures, which occupy only a small proportion of the patient’s life, does not seem to address many of the issues that have an adverse impact on the quality of life of the patient with epilepsy.
Sackellares and Berent stated that comprehensive care of the epileptic patient requires “attention to the psychological and social consequences of epilepsy as well as to the control of seizures.”
Although undoubtedly important in the care of the patient with epilepsy, advances in neurologic diagnosis and treatment tended to obscure the behavioral manifestations of epilepsy until Gibbs drew attention to the high incidence of behavioral disorders in patients with temporal lobe epilepsy.
Frequency of psychiatric disorders in patients with epilepsy
It is estimated that 20-30% of patients with epilepsy have psychiatric disturbances.
Of patients with intractable complex partial seizures, 70% may have 1 or more diagnoses consistent with the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R); 58% of these patients have a history of depressive episodes, 32% have agoraphobia without panic or other anxiety disorder, and 13% have psychoses.
The risk of psychosis in patients with epilepsy may be 6-12 times that of the general population, with a prevalence of about 7-8%; in patients with treatment-refractory temporal lobe epilepsy, the prevalence has been reported to range from 0-16%.
Differences in the rates may result from differences in the populations studied, time periods investigated, and diagnostic criteria.
The most common psychiatric conditions in epilepsy are depression, anxiety, and psychoses.
(See the Table below.)
Table. Prevalence Rates of Psychiatric Disorders in Patients With Epilepsy and the General Population (2007 data)
(Open Table in a new window)
Patients With Epilepsy
Major depressive disorder
The psychiatric symptoms characteristic of the neurobehavioral syndrome of epilepsy (ie, Morel syndrome) tend to be distinguished in the following ways:
Atypical for the psychiatric disorder