Introduction (2005)

The links between epilepsy and psychiatry have been discussed for many years, and a number of controversies have been generated. However, it now seems reasonably secure that patients with epilepsy have behavior disorders with greater frequency than do patients who do not have epilepsy, but that the spectrum of the psychopathology is wide. It ranges from the more severe psychoses to anxiety disorders and minor depression. The associations between site and type of lesion leading to epilepsy and the effects of antiepileptic drugs (AEDs) and seizure suppression on psychopathology emphasize several aspects of the underlying neurobiology. One of the more established areas of overlap is the use of AEDs for the management of psychopathologies in patients who do not have epilepsy. This story emerged in the 1960s in particular, with observations that valproate and carbamazepine (CBZ) had mood-stabilizing properties in people with recurrent mood disorders, particularly those with bipolar disorder. These compounds, which are now referred to as AEDs, clearly have effects that go well beyond the straightforward suppression of seizures. Indeed, they are all neuromodulators, as are, for example, antiparkinsonian drugs, antidepressants, and antipsychotic medications. What seems to be emerging, however, is that being antiepileptic is not a sine qua non for having an effect on mood, and neither is simply having a mood disorder an indication for the prescription of one of the AED compounds. Indeed, it is refreshing to learn, as information is slowly gathered over time, that only some AEDs seem to possess effects on mood, although it is an axiom that nearly all AEDs that are brought to the market for the management of epilepsy are now investigated for their potential mood-stabilizing effects. This is important in the sense that it leads to further explorations of the underlying neurophysiology and neurochemistry of bipolar disorders and leads to the potential for the development of other mood-stabilizing compounds. With regard to psychiatry, more recent studies are suggesting which patients may respond to individual drugs and over what length of time. The authors of this supplement, acting under the auspices of the Commission on Psychobiology of the Internal League Against Epilepsy, continue to emphasize the overlaps between neurology and psychiatry and, in particular, emphasize the importance of a neuropsychiatric perspective to the overall management of patients with epilepsy. To these ends, with an unrestricted educational grant from Glaxo SmithKline, the authors collected a group of experts who had been working in the field of either epilepsy, mood disorders, or both, with a view to updating information in this interface area for interested researchers and clinicians. The necessity of the meeting was emphasized further by the introduction (in the last 15 years) of some 11 new AEDs, which are now gradually percolating, through clinical trials, into an established clinical use in either epilepsy, mood disorders, or both. The monograph begins with an attempt to clarify the current diagnostic criteria for various bipolar disorders, which is followed by a chapter on epidemiology. These chapters emphasize the wide spectrum of clinical presentations now accepted under the rubric of bipolar disorder, but also, with this broader spectrum, the considerable frequency in clinical practice with which these disorders are met. The next three chapters concentrate on the underlying neurobiology of bipolar disorders, with new data on both brain imaging and neuropsychology that emphasize not only the often unrecognized underlying cerebral changes to be found in bipolar disorders, but also the enduring interphase mental state, which is one of continuing cognitive deficits and mood instability. The next article, which deals with the clinical pharmacology of the old and new AEDs, appears before an article on the use of these AEDs in the management of bipolar disorder. This is followed by a discussion of the spectrum of mood disorders in epilepsy and their similarities and differences compared with that in patients who do not have seizure disorders. The final chapter examines data on mood regulation and quality of life in patients with epilepsy prescribed these AEDs, emphasizing a continuous history on this matter going back to the early use of CBZ in the 1960s through to the present. The editors hope that the volume will be of clinical value to those who treat either patients with epilepsy who have associated mood disorders, or patients with mood disorders who do not have epilepsy, and are seeking information as to additional psychopharmacologic management strategies. It also is hoped that this will stimulate further research into the neuropsychiatry of the epilepsies and aid in promoting investigation of the underlying neurobiologies of recurrent mood instability.