Excerpt from Psychiatric Disorders Associated With Epilepsy

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Both neurology and psychiatry deal with diseases of the same organ—the brain. Predicting interaction between neurologic and psychiatric diseases is not, therefore, unreasonable. In an editorial in the journal Neurology in 2000, Price, Adams, and Coyle explored these interactions. The clinical relationship between epilepsy and behavioral disorders remains controversial.

Some authors find a greater incidence of behavioral disorders in patients with epilepsy than in the general population. Other authors argue that this apparent overrepresentation is due to sampling errors or inadequate control groups. Mechanisms for such a relationship include the following:

• Common neuropathology
• Genetic predisposition
• Developmental disturbance
• Ictal or subictal neurophysiological effects
• Inhibition or hypometabolism surrounding the epileptic focus
• Secondary epileptogenesis
• Alteration of receptor sensitivity
• Secondary endocrinologic alterations
• Primary, independent psychiatric illness
• Consequence of medical or surgical treatment
• Consequence of psychosocial burden of epilepsy

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. Agreement now is general that the incidence of neurobehavioral disorders is higher in patients with epilepsy than in the general population. 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. Edeh and Toone asserted that the difference is between focal epilepsies, both temporal lobe and nontemporal lobe, and primary generalized epilepsy.

Vuilleumier and Jallon estimated that 20-30% of patients with epilepsy have psychiatric disturbances. Tucker reported that one study found that 70% of patients with intractable complex partial seizures had one or more diagnoses consistent with Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R)—58% had a history of depressive episodes, 32% had agoraphobia without panic or other anxiety disorder, and 13% had psychoses. Torta and Keller reported that the risk of psychosis in populations of patients with epilepsy may be 6-12 times that in 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 populations studied, time periods investigated, and diagnostic criteria.

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
• Episodic
• Pleomorphic

In studying the relationship between epilepsy and psychiatric disorders, care must be taken to differentiate between the following:

• Psychiatric disorders caused by the seizures of the epilepsy - Ictal disorders, postictal disorders, and interictal disorders
• Epileptic and psychiatric disorders caused by common brain pathology
• Epileptic and psychiatric disorders that happen to coexist in the same patient but are not causally related

Schmitz et al found that multiple interacting biological and psychosocial factors determine the risk for development of either schizophreniform psychoses or major depression in patients with epilepsy and concluded that behavioral disorders in epilepsy had multiple risk factors and multifactorial etiology.

For excellent patient education resources, visit eMedicine's Brain and Nervous System Center. Also, see eMedicine's patient education article Epilepsy.

Please click here to view the full topic text: Psychiatric Disorders Associated With Epilepsy